Microbiology Research

13 pages, 1857 KiB

Open AccessArticle

Isolation and Characterization of Fungal Endophytes from Petiveria alliacea and Their Antimicrobial Activities in South Florida

by Ganesh Khadka, Thirunavukkarasu Annamalai, Kateel G. Shetty, Yuk-Ching Tse-Dinh and Krish Jayachandran

Microbiol. Res. 2023, 14(3), 1470-1482; https://doi.org/10.3390/microbiolres14030100 - 19 Sep 2023

Cited by 2 | Viewed by 3017

Abstract

Microorganisms associated with medicinal plants are of great interest as they are the producers of important bioactive compounds effective against common and drug-resistant pathogens. The characterization and biodiversity of fungal endophytes of the Petiveria alliacea plant and their antimicrobial production potential are of [...] Read more.

Microorganisms associated with medicinal plants are of great interest as they are the producers of important bioactive compounds effective against common and drug-resistant pathogens. The characterization and biodiversity of fungal endophytes of the Petiveria alliacea plant and their antimicrobial production potential are of great interest as they are known for their antimicrobial and anticancer properties. In this study, we investigated the endophytic fungal microbiome associated with P. alliacea, and the endophytic fungal isolates were classified into 30 morphotypes based on their cultural and morphological characteristics. Ethyl acetate extract of fungal endophytes was obtained by liquid–liquid partitioning of culture broth followed by evaporation. The crude extract dissolved in dimethyl sulfoxide was screened for antimicrobial activity against three bacterial strains (Escherichia coli ATTC 25902, Staphylococcus aureus ATTC 14775, Bacillus subtilis NRRL 5109) and two fungal strains (Candida albicans ATTC 10231 and Aspergillus fumigatus NRRL 5109). Among the crude extracts from endophytes isolated from leaves, 65% of them showed antimicrobial activity against the bacteria tested. Similarly, 71 and 88% of the fungal crude extracts from endophytes isolated from root and stem, respectively, showed inhibitory activities against at least one of the bacterial strains tested. Crude extracts (at a concentration of 10 mg/mL) from ten of the fungal isolates have shown a zone of inhibition of more than 12 mm against both Gram-positive and negative bacteria tested. Sequenced data from isolates showing strong inhibitory activity revealed that Fusarium solani, F. proliferatum, and Fusarium oxysporium are the major endophytes responsible for bioactive potential. These results indicate that Petiveria alliacea harbors fungal endophytes capable of producing antimicrobial metabolites. Future studies need to focus on testing against drug-resistant bacteria (ESKAPE group) and other pathogenic bacteria and fungi. Full article

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13 pages, 2332 KiB

Open AccessReview

The Different Types of Metallophores Produced by Salmonella enterica: A Review

by Yehya Mohsen, Nathalie Tarchichi, Rana Barakat, Inas Kawtharani, Rayane Ghandour, Zeinab Ezzeddine and Ghassan Ghssein

Microbiol. Res. 2023, 14(3), 1457-1469; https://doi.org/10.3390/microbiolres14030099 - 19 Sep 2023

Cited by 1 | Viewed by 1086

Abstract

Salmonella enterica (S. enterica) serovars Enteritidis and Typhimurium are the main causes of bacterial gastroenteritis worldwide. This Gram-negative rods bacterium possesses several virulence factors that enable it to survive the host’s nutritional immunity. Toxins and metallophores are among these factors. Heavy [...] Read more.

Salmonella enterica (S. enterica) serovars Enteritidis and Typhimurium are the main causes of bacterial gastroenteritis worldwide. This Gram-negative rods bacterium possesses several virulence factors that enable it to survive the host’s nutritional immunity. Toxins and metallophores are among these factors. Heavy metals, in particular, are essential for the survival of all living organisms including bacteria. During infection, S. enterica competes with the host for the available heavy metals by secreting metallophores, which are secondary metabolites. Once produced in the extracellular medium, metallophores complex heavy metals thus allowing Salmonella to acquire metal ions through importing them via channels embedded in their membranes. This review highlights the biosynthesis, export, import, and genetic regulation of different metallophores synthesized by this germ. Full article

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15 pages, 2481 KiB

Open AccessArticle

Postbiotics of the Lactiplantibacillus plantarum EIR/IF-1 Strain Show Antimicrobial Activity against Oral Microorganisms with pH Adaptation Capability

by Basar Karaca, Mervi Gursoy, Fadime Kiran, Vuokko Loimaranta, Eva Söderling and Ulvi Kahraman Gursoy

Microbiol. Res. 2023, 14(3), 1442-1456; https://doi.org/10.3390/microbiolres14030098 - 18 Sep 2023

Viewed by 897

Abstract

Postbiotics offer better properties than probiotics. This study investigated the antimicrobial activity of Lactiplantibacillus plantarum EIR/IF-1 postbiotics against pH-adaptive bacteria, namely Prevotella denticola, Fusobacterium nucleatum, and Streptococcus sanguinis. Cell-free culture media of L. plantarum EIR/IF-1 were used as postbiotics in [...] Read more.

Postbiotics offer better properties than probiotics. This study investigated the antimicrobial activity of Lactiplantibacillus plantarum EIR/IF-1 postbiotics against pH-adaptive bacteria, namely Prevotella denticola, Fusobacterium nucleatum, and Streptococcus sanguinis. Cell-free culture media of L. plantarum EIR/IF-1 were used as postbiotics in either crude (acidic) or neutralized form to also understand non-pH-dependent antimicrobial potential. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and viable cell counts were determined for crude and neutralized postbiotics. Culture media adjusted to different pH values were also compared to adjusted media with postbiotics to understand the strength of organic acids in postbiotics. Antibiofilm activity of postbiotics was determined against polymicrobial biofilm formation. Finally, the toxicity of crude postbiotics was tested on human periodontal ligament fibroblast cells (hPDLFCs). MIC values of crude postbiotics were 12.5 mg/mL for all strains. F. nucleatum and P. denticola strains were sensitive to neutralized postbiotics after 48 h of incubation. Moreover, 12.5 and 25 mg/mL postbiotics inhibited biofilm formation and 2.5 mg/mL and lower concentrations of crude postbiotics showed no cytotoxicity in hPDLFCs. This study showed that postbiotics have antimicrobial activity against pH-adaptive oral bacteria and no cytotoxic effect on hPDLFCs depending on the dose. The non-acidic antimicrobial components of postbiotics could also enable their safe use in the oral cavity. Full article

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15 pages, 2681 KiB

Open AccessArticle

Integrated Analysis of Long Non-Coding RNA Expression Profiles in Glaesserella parasuis-Induced Meningitis: New Insight into Pathogenesis

by Peiyan Sun, Yaqiong Yang, Hongxing Cheng, Shulin Fu, Yulan Liu, Yinsheng Qiu, Hongbo Chen, Jing Zhang, Huanhuan Zhou, Liangyu Shi, Hongyan Ren, Zhe Chao and Ling Guo

Microbiol. Res. 2023, 14(3), 1427-1441; https://doi.org/10.3390/microbiolres14030097 - 18 Sep 2023

Cited by 1 | Viewed by 919

Abstract

Glaesserella parasuis (G. parasuis) can elicit meningitis in pigs; however, the pathogenic mechanisms of meningitis induced by G. parasuis remain unclear. Long non-coding RNAs (lncRNAs) have been proven to play key roles in a variety of physiological and pathological processes. However, [...] Read more.

Glaesserella parasuis (G. parasuis) can elicit meningitis in pigs; however, the pathogenic mechanisms of meningitis induced by G. parasuis remain unclear. Long non-coding RNAs (lncRNAs) have been proven to play key roles in a variety of physiological and pathological processes. However, whether lncRNAs are involved in meningitis triggered by G. parasuis has not been investigated. In this study, we performed an integrative analysis of lncRNAs expression profiles in the porcine brain infected with G. parasuis using RNA-seq. The results showed that lncRNA expressions in G. parasuis-induced meningitis were modified, and a total of 306 lncRNAs exhibited significant differential expression, in which 176 lncRNAs were up-regulated and 130 lncRNAs were down-regulated. KEGG enrichment analysis demonstrated that the differentially expressed target mRNAs of affected lncRNAs in G. parasuis-infected porcine brain were mainly involved in the cell adhesion molecules (CAMs), Jak-STAT signaling pathway, PI3k-Akt signaling pathway, and TNF signaling pathway. The expression relationship between the most affected differential lncRNAs and their differential target mRNAs was visualized by a co-expression network. A protein-protein interaction network consisting of 12 differential targets was constructed using STRING analysis. In addition, differential expressions of important lncRNAs were validated by qRT-PCR. lncRNA ALDBSSCT0000007362, ALDBSSCT0000001959, ALDBSSCT0000005529, MSTRG.2939.1, and MSTRG.32374.1 showed the same expression pattern with the lncRNA sequencing data. Our results demonstrated that G. parasuis could modify the lncRNA expression profiles in the porcine brain. To the best of our knowledge, this is the first report revealing the integrative analysis of lncRNA expression profiles in G. parasuis-induced meningitis, which could enhance important information to understand the inflammatory functions of lncRNAs involved in swine meningitis, and also provide a foundation for finding out novel strategies to prevent and treat meningitis in piglets triggered by G. parasuis. Full article

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14 pages, 3532 KiB

Open AccessArticle

Enhancing the Biodiesel Production by Improving the Yield of Lipids in Wild Strain by Inducing Nitrogen Ion Mutation in Rhodotorula mucilaginosa

by Joseph Antony Sundarsingh Tensingh and Vijayalakshmi Shankar

Microbiol. Res. 2023, 14(3), 1413-1426; https://doi.org/10.3390/microbiolres14030096 - 18 Sep 2023

Viewed by 835

Abstract

The overconsumption of energy results in the depletion of fossil fuels. Generally, biodiesels are produced from wastes of animal fats and vegetable oils. In this study, we have tried to produce biodiesel from both the wild strain and ion beam mutated strain and [...] Read more.

The overconsumption of energy results in the depletion of fossil fuels. Generally, biodiesels are produced from wastes of animal fats and vegetable oils. In this study, we have tried to produce biodiesel from both the wild strain and ion beam mutated strain and compared the concentration of lipids produced from both the strains and their properties. Lipids were extracted from microbes using the Bligh and Dyer method and analyzed using gas chromatography and mass spectrophotometry (GCMS) and Fourier-transform infrared (FTIR) spectroscopy. Extracted lipids (free fatty acids) were converted into biodiesel (fatty acid methyl esters) using a base catalyst. The end product biodiesel was characterized and analyzed based on ASTM standards. Full article

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15 pages, 3016 KiB

Open AccessArticle

Evaluation of Lacc134 Oxidoreductase of Ganoderma multistipitatum in Detoxification of Dye Wastewater under Different Nutritional Conditions

by Eman A. Alhomaidi, Aisha Umar, Salam S. Alsharari and Sami Alyahya

Microbiol. Res. 2023, 14(3), 1398-1412; https://doi.org/10.3390/microbiolres14030095 - 18 Sep 2023

Viewed by 1082

Abstract

In the present study, we investigated the effects of different carbon sources (glucose, sucrose, and maltose) on laccase production from mycelium of Ganoderma multistipitatum grown on malt extract agar plates. The preliminary screening test was performed on the guaiacol plate, where a maroon [...] Read more.

In the present study, we investigated the effects of different carbon sources (glucose, sucrose, and maltose) on laccase production from mycelium of Ganoderma multistipitatum grown on malt extract agar plates. The preliminary screening test was performed on the guaiacol plate, where a maroon brown zone formed after laccase oxidation. A few pure mycelial discs of Ganoderma species were transferred into submerged fermentation nutrient broth. The nutrient medium of submerged fermentation at 20 g of glucose revealed the highest laccase activities (2300 U/L) than other carbon sources. The interesting results also shown by inorganic NaNO₃ in the production of maximum laccase (7800 ± 1.1 U/L). The organic nitrogen inducer, namely yeast extract, exhibited 5834 U/L laccase activity and a potential source of laccase secretion. The results concluded that C and N inducers enhanced the laccase production. This production process is eco-friendly and effective in the removal of dye from water. Laccase from the cultural broth was partially purified by SDS-PAGE for molecular weight determination, while Native-PAGE confirmed the laccase band after staining with guaiacol. The Km and Vmax values of Lacc134 were 1.658 mm and 2.452 mM min⁻¹, respectively. The Lacc134 of this study effectively removed the Remazol Brilliant Blue R (RBBR) dye (extensively used in textile industries and wastewater). For dye removal capacity, 2.0 mg, 4.0 mg, 5.0 mg, and 6.0 mg were used, from which 6.0 mg was most effective in removal (85% and 88%) dye concentration in 1st and 2nd h interval treatment, respectively. Total organic carbon (TOC) quantity after dye removal percentage in the first- and second-hour time interval was 62% and 89%, respectively, at 30 g glucose. According to the experimental finding of this study, the breakdown products catalyzed by Lacc134 are less hazardous due to lower molecular weight than the dye itself. Full article

(This article belongs to the Special Issue Microorganisms as a Tool for Restoring the Environment)

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22 pages, 1445 KiB

Open AccessReview

Clustering Disease of Clostridioides Difficile Infection: Implication for the Management in Internal Medicine

by Pietro Crispino

Microbiol. Res. 2023, 14(3), 1376-1397; https://doi.org/10.3390/microbiolres14030094 - 15 Sep 2023

Viewed by 1147

Abstract

Clostridioides difficile is a bacterium responsible for a healthcare-associated gastrointestinal infection, primarily affecting people who have undergone prolonged antibiotic treatment or who have compromised immune systems. The CD is of particular concern due to its high recurrence rates and the potential for serious [...] Read more.

Clostridioides difficile is a bacterium responsible for a healthcare-associated gastrointestinal infection, primarily affecting people who have undergone prolonged antibiotic treatment or who have compromised immune systems. The CD is of particular concern due to its high recurrence rates and the potential for serious outcomes, including life-threatening conditions such as pseudomembranous colitis, septic shock, and all associated conditions. Since this infection is a disease associated with other health conditions, a general vision of the problems is necessary which aims to obtain a general overview of the manifestations that generally correlate with care. Clinical reasoning following the disease-clustering method is able to produce a categorization process by grouping the possible correlations of the various conditions or factors underlying diseases on the basis of certain similarities or common models. The clustering process is performed using data analysis techniques which, by statically correlating each other, give an exact dimension of all the information related to a particular disease. In the case of CD, reasoning based on disease clustering has better clarified the practices, appropriateness in infection control, judicious use of antibiotics, and research into therapeutic and preventive strategies. This review, taking advantage of the clustering strategy, aimed to analyze the contingent conditions of the infection under examination, to reduce the incidence and impact of CD, having as its mission the improvement of the results deriving from the contrast of all those correlated pathological conditions to healthcare for the improvement of public health. Full article

(This article belongs to the Special Issue Current Progress in Prion Research)

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12 pages, 840 KiB

Open AccessArticle

The Influence of Pre-Existing Immunity against Human Common Cold Coronaviruses on COVID-19 Susceptibility and Severity

by Erick De La Torre Tarazona, Daniel Jiménez, Daniel Marcos-Mencía, Alejandro Mendieta-Baro, Alejandro Rivera-Delgado, Beatriz Romero-Hernández, Alfonso Muriel, Mario Rodríguez-Domínguez, Sergio Serrano-Villar and Santiago Moreno

Microbiol. Res. 2023, 14(3), 1364-1375; https://doi.org/10.3390/microbiolres14030093 - 14 Sep 2023

Viewed by 919

Abstract

The susceptibility to SARS-CoV-2 infection and the severity of COVID-19 manifestations vary significantly among individuals, prompting the need for a deeper understanding of the disease. Our objective in this study was to investigate whether previous infections with human common cold coronaviruses (hCCCoV) might [...] Read more.

The susceptibility to SARS-CoV-2 infection and the severity of COVID-19 manifestations vary significantly among individuals, prompting the need for a deeper understanding of the disease. Our objective in this study was to investigate whether previous infections with human common cold coronaviruses (hCCCoV) might impact susceptibility to and the progression of SARS-CoV-2 infections. We assessed the serum antibody levels against SARS-CoV-2 and four hCCCoV (H-CoV-OC43, -NL63, -HKU1, and -229E) in three distinct populations: 95 uninfected individuals (COVID-19-negative), 83 individuals with mild or asymptomatic COVID-19 (COVID-19-mild), and 45 patients who died due to COVID-19 (COVID-19-severe). The first two groups were matched in terms of their exposure to SARS-CoV-2. We did not observe any differences in the mean antibody levels between the COVID-19-mild and the COVID-19-negative participants. However, individuals in the COVID-19-mild group exhibited a higher frequency of antibody levels (sample/control) > 0.5 against H-CoV-HKU1, and >1 against H-CoV-229E and -OC43 (p < 0.05). In terms of severity, we noted significantly elevated H-CoV-NL63 IgG levels in the COVID-19-severe group compared to the other groups (p < 0.01). Our findings suggest a potential mild influence of hCCCoV antibody levels on the susceptibility to SARS-CoV-2 infection and the severity of COVID-19. These observations could aid in the development of strategies for predicting and mitigating the severity of COVID-19. Full article

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11 pages, 1087 KiB

Open AccessArticle

The Triterpenoid High-Performance Liquid Chromatography Analytical Profiles of the Mycelia of Ganoderma lucidum (lingzhi)

by Deng-Hai Chen, Jian-Yuan Wang, Mon-Tarng Chen, Yen-Chun Liu and Kuang-Dee Chen

Microbiol. Res. 2023, 14(3), 1353-1363; https://doi.org/10.3390/microbiolres14030092 - 14 Sep 2023

Viewed by 1067

Abstract

(1) Background: Ganoderic acids (GAs) are specific triterpenes of Ganoderma lucidum. The HPLC fingerprint profile of GAs of the fruiting body is well known, but their mycelial fingerprinting remains unclear. (2) Methods: An ethanol extract of the mycelium of G. lucidum (YK-0 [...] Read more.

(1) Background: Ganoderic acids (GAs) are specific triterpenes of Ganoderma lucidum. The HPLC fingerprint profile of GAs of the fruiting body is well known, but their mycelial fingerprinting remains unclear. (2) Methods: An ethanol extract of the mycelium of G. lucidum (YK-01) was further purified via preparative HPLC. The triterpenoid compositions for four strains of G. lucidum and one strain of G. formosanum (purple lingzhi) were analyzed using HPLC. (3) Results: Nineteen lanostane triterpenes, including five new triterpenes, GA-TP (1), ganodermic acid J_c (GmA-J_c) (2), GmA-J_d (3), GA-TQ₁ (4), and ganoderal B₁ (5), and fourteen known triterpenes 6–19 were isolated from the ethanol extract. Their structures were identified by mass and extensive NMR spectroscopy. A green chemical HPLC analytical method was developed using ethanol and acetic acid as a mobile phase, and all isolated compounds can be well separated. These triterpenes comprise a unique HPLC chromatograph of the G. lucidum mycelium. All four G. lucidum strains showed the same HPLC chromatographic pattern, whereas G. formosanum displayed a different pattern. Quantitation methods for ganoderic acid T (10) and S (12) were also validated. (4) Conclusions: The triterpenoid HPLC analytical method can be used to identify the G. lucidum species and to determine the contents of GA-T and GA-S. Full article

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10 pages, 1219 KiB

Open AccessCase Report

Eradication of Bovine Mastitis Caused by the Pathogenic Microalga Prototheca bovis on a Dairy Cattle Farm: A Case Report

by Monika Beinhauerova, Monika Moravkova, Ruzena Seydlova and Magdalena Crhanova

Microbiol. Res. 2023, 14(3), 1343-1352; https://doi.org/10.3390/microbiolres14030091 - 13 Sep 2023

Viewed by 1081

Abstract

The achlorophyllous unicellular microalga of the genus Prototheca, a causative agent of bovine mammary gland infection, is receiving increasing attention in the field of veterinary medicine. Mastitis caused by these algae leads to significant economic losses for farmers worldwide and represents a [...] Read more.

The achlorophyllous unicellular microalga of the genus Prototheca, a causative agent of bovine mammary gland infection, is receiving increasing attention in the field of veterinary medicine. Mastitis caused by these algae leads to significant economic losses for farmers worldwide and represents a source of threat to raw milk quality and dairy food-chain safety. This case report describes an outbreak of bovine mastitis in dairy cattle caused by Prototheca bovis and the on-farm practices that resulted in the recovery of the affected herd and elimination of the presence of Prototheca spp. in the farm environment. Effective management strategies that played a crucial role in protothecosis eradication included regular screening, timely identification, strict separation of Prototheca-positive cows, a change of housing regime associated with the utilisation of straw mattresses and removal of deep bedding and, finally, the introduction of intermediate disinfection of teat cups with peracetic acid to prevent the spread of infection to other healthy individuals. The eradication process lasted approximately three years and required the removal of 139 cows from the farm. The corrective and preventive measures described in this case report provide guidance to farmers on how to successfully deal with protothecal mastitis on farms. Full article

(This article belongs to the Collection Public Health and Quality Aspects Related to Animal Productions)

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12 pages, 2654 KiB

Open AccessArticle

Molecular Epidemiology of Porcine Circovirus Type 2 and Porcine Parvoviruses in Guangxi Autonomous Region, China

by Pin Chen, Geng Wang, Jiping Chen, Weichao Zhang, Yin He and Ping Qian

Microbiol. Res. 2023, 14(3), 1331-1342; https://doi.org/10.3390/microbiolres14030090 - 13 Sep 2023

Viewed by 954

Abstract

Both porcine circovirus (PCV) and porcine parvovirus (PPV) cause various diseases and bring huge economic losses to the global swine industry. PCV2 is associated with several diseases and syndromes, including postweaning multisystemic wasting syndrome (PMWS), porcine dermatitis and nephropathy syndrome (PDNS) and porcine [...] Read more.

Both porcine circovirus (PCV) and porcine parvovirus (PPV) cause various diseases and bring huge economic losses to the global swine industry. PCV2 is associated with several diseases and syndromes, including postweaning multisystemic wasting syndrome (PMWS), porcine dermatitis and nephropathy syndrome (PDNS) and porcine respiratory disease complex (PRDC). The classical PPV is one of the most common causes of reproductive failure in pigs. In this study, tissue samples (tonsil, lung, mesenteric lymph node, hilar lymph node and superficial inguinal lymph node) were collected from pigs with suspected PCV2-associated disease (PCVAD), and viral DNA was extracted. The coinfection of PCV2 and PPV1–5 was detected using the polymerase chain reaction (PCR) method. Phylogenetic analysis based on capsid genes of PCV2, PPV2, PPV3 and PPV5 was conducted. The prevalence rates of PCV2, PPV1, PPV2, PPV3, PPV4 and PPV5 were 51.2%, 15.9%, 36.6%, 19.5%, 14.6% and 10.9% on the individual pig level, respectively. The coinfection rates of PCV2 with PPV1, PPV2, PPV3, PPV4 and PPV5 were 8.5%, 25.6%, 17.1%, 13.4% and 3.7%, respectively. The prevalence of PPV2, PPV3 and PPV4 in PCV2-positive pigs was significantly higher than those in PCV2-negative pigs. Phylogenetic analyses were performed using the neighbor-joining (NJ) method with 1000 bootstraps. The results indicated the existence of PCV2d and two major clusters of PPV2, PPV3 and PPV5 in the Guangxi Autonomous Region. PCV2d was the dominant strain, and the novel PPVs were circulating in domestic pigs in the Guangxi Autonomous Region. The results of this study underline the importance of active surveillance of PCV2d and PPVs from the swine population in this area. Full article

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12 pages, 2499 KiB

Open AccessArticle

Aureimonas altamirensis: First Isolation from a Chicken Slaughterhouse in Italy Followed by Genotype and Phenotype Evaluations

by Davide Buzzanca, Elisabetta Chiarini, Ilaria Mania, Francesco Chiesa and Valentina Alessandria

Microbiol. Res. 2023, 14(3), 1319-1330; https://doi.org/10.3390/microbiolres14030089 - 12 Sep 2023

Cited by 1 | Viewed by 1224

Abstract

The presence of foodborne pathogens in meat is linked to several contamination sources, and the slaughterhouse environment represents a relevant reservoir of contamination. Aureimonas altamirensis is a Gram-negative bacteria associated with different isolation sources, including human clinical cases. This study aims to identify [...] Read more.

The presence of foodborne pathogens in meat is linked to several contamination sources, and the slaughterhouse environment represents a relevant reservoir of contamination. Aureimonas altamirensis is a Gram-negative bacteria associated with different isolation sources, including human clinical cases. This study aims to identify and characterize an A. altamirensis isolate from chicken guts collected in an Italian slaughterhouse. The study approach includes whole-genome analysis jointly with phenotypical tests. Whole-genome sequencing (WGS) confirms the initial MALDI-TOF MS identification, finding putative virulence and biofilm-related genes. Moreover, the gene class evaluation reveals that the numerically largest gene category in the A. altamirensis genome is related to amino acid metabolism and transport. The analyses performed on a human gut mucus-producing cell line (HT29-MTX-E12) demonstrated the ability of A. altamirensis to colonize the host cell layer. Moreover, the antibiotic resistance test showed a high resistance of A. altamirensis to gentamicin (MIC 0.5 mg/L). The detection of a potential pathogenic and antibiotic-resistant A. altamirensis strain isolated from a slaughterhouse underlines the necessity of active surveillance studies focused on this species and the need for further studies about A. altamirensis in foods. Full article

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18 pages, 4122 KiB

Open AccessArticle

Trichoderma Species Problematic to the Commercial Production of Pleurotus in Italy: Characterization, Identification, and Methods of Control

by Nadia Lombardi, Angela Pironti, Gelsomina Manganiello, Roberta Marra, Francesco Vinale, Stefania Vitale, Matteo Lorito and Sheridan Lois Woo

Microbiol. Res. 2023, 14(3), 1301-1318; https://doi.org/10.3390/microbiolres14030088 - 12 Sep 2023

Viewed by 1310

Abstract

Nine isolates of Trichoderma were obtained from the diverse phases of compost preparation and the production of different commercial varieties of oyster mushrooms Pleurotus spp. with the apparent presence of green mould disease. The isolates were morphologically and genetically characterized. Molecular fingerprinting indicated [...] Read more.

Nine isolates of Trichoderma were obtained from the diverse phases of compost preparation and the production of different commercial varieties of oyster mushrooms Pleurotus spp. with the apparent presence of green mould disease. The isolates were morphologically and genetically characterized. Molecular fingerprinting indicated that the isolates belonged to the species T. pleuroticola and T. harzianum. In order to identify control measures, changes in temperature, pH, and application of fungicides were tested on the present isolates, using known Trichoderma biocontrol strains as a reference. Fungicide effects on the growth of Pleurotus isolates were also assessed. The optimal growth temperatures were 25 °C for Trichoderma isolates and 28 °C for Pleurotus isolates, and Trichoderma always grew faster than Pleurotus. In particular, a reduction of about 30% was recorded for some of the Trichoderma isolates when comparing the colony growth at 25 and 28 °C. Trichoderma isolates developed well within a wide pH range, with the best growth occurring between pH 5 and 7, whereas Pleurotus preferred more alkaline conditions (pH 8 to 9). Prochloraz and metrafenone were found to inhibit Trichoderma growth with different dose responses that did not affect the growth of Pleurotus spp. In particular, metrafenone was the most effective active ingredient that inhibited the majority of the Trichoderma isolates (1–25% growth reduction). Full article

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10 pages, 1052 KiB

Open AccessBrief Report

Unveiling the Potency and Harnessing the Antibacterial Activities of Plant Oils against Foodborne Pathogens

by Vijaya Samoondeeswari Selvarajan, Ramganesh Selvarajan, Jeevan Pandiyan and Akebe Luther King Abia

Microbiol. Res. 2023, 14(3), 1291-1300; https://doi.org/10.3390/microbiolres14030087 - 09 Sep 2023

Viewed by 1572

Abstract

The rising concerns regarding antibiotic resistance and the harmful effects of synthetic preservatives have led to an increasing interest in exploring natural alternatives. Plant oils have been traditionally used for their antimicrobial properties, but systematic investigations into their efficacy against foodborne pathogens are [...] Read more.

The rising concerns regarding antibiotic resistance and the harmful effects of synthetic preservatives have led to an increasing interest in exploring natural alternatives. Plant oils have been traditionally used for their antimicrobial properties, but systematic investigations into their efficacy against foodborne pathogens are necessary for potential applications in food preservation. This study aimed to evaluate the antibacterial potential of various plant oils (neem, coconut, castor, and olive oil) against common foodborne pathogens and analyze their chemical composition using gas chromatography–mass spectrometry (GC-MS). The oils were tested against foodborne pathogens using the disk diffusion method. Minimum inhibitory concentrations (MICs) were determined to assess the potency of the oils. GC-MS was employed to identify the compounds present in each oil. Neem oil exhibited significant antibacterial activity against all tested pathogens, with pronounced effects against Staphylococcus aureus and Bacillus cereus. Coconut oil showed notable activity against Listeria monocytogenes. Castor oil displayed moderate activity, while olive oil exhibited minimal antibacterial effects. The GC-MS analysis revealed a diverse array of compounds in neem oil, which is likely to contribute to its potent antibacterial properties. Neem and coconut oils, owing to their rich bioactive components, emerged as promising candidates for the development of natural antimicrobial agents. These brief findings support the potential application of plant oils in food preservation and emphasize the need for further research into understanding the underlying mechanisms and optimizing their use. Full article

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12 pages, 840 KiB

Open AccessArticle

The Molecular Epidemiology of Clostridioides difficile Infection in Central India: A Prospective Observational Cohort Study

by Rima Biswas, Nick Pinkham, Seth T. Walk, Qian Wang, Shrikant Ambalkar, Ashish R. Satav, Mark H. Wilcox, Rahul Reghunath, Kiran Chawla, Padmaja A. Shenoy, Amit R. Nayak, Aliabbas A. Husain, Dhananjay V. Raje, Rajpal Singh Kashyap and Tanya M. Monaghan

Microbiol. Res. 2023, 14(3), 1279-1290; https://doi.org/10.3390/microbiolres14030086 - 08 Sep 2023

Viewed by 1089

Abstract

This prospective observational cohort study aimed to establish and compare baseline rates of Clostridioides difficile infection (CDI) in community and hospitalized patients in Nagpur and rural Melghat Maharashtra, including adults aged ≥18 years with a diagnosis of diarrhoea as defined as 3 or [...] Read more.

This prospective observational cohort study aimed to establish and compare baseline rates of Clostridioides difficile infection (CDI) in community and hospitalized patients in Nagpur and rural Melghat Maharashtra, including adults aged ≥18 years with a diagnosis of diarrhoea as defined as 3 or more loose stools in a 24 h period. All diarrhoeal samples were tested for CDI using the C. diff Quik Chek Complete enzyme immunoassay. C. difficile-positive stool samples were characterised by toxigenic culture, antimicrobial susceptibility testing and PCR ribotyping. C. difficile testing was performed on 1683 patients with acute diarrhoea. A total of 54 patients (3.21%; 95% CI: 2.42–4.17) tested positive for both the GDH antigen and free toxin. The risk factors for CDI included the presence of co-morbidities, antibiotic usage, and immunosuppression. The detected PCR ribotypes included 053-16, 017, 313, 001, 107, and 216. Our findings show that toxigenic C. difficile is an important but neglected aetiologic agent of infective diarrhoea in Central India. These results underscore the need to enhance the awareness and testing of patients with diarrhoea in India regarding the presence of toxigenic C. difficile, particularly in high-risk individuals with multiple co-morbidities, immunosuppression, and recent or ongoing antibiotic exposure or hospitalization. Full article

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15 pages, 31618 KiB

Open AccessArticle

Evaluation of Compounds from Balanites aegyptiaca against Squalene Epoxidase of Micropsorum gypseum—In Vitro and In Silico Studies

by Mohamed Husain Syed Abuthakir, V. Hemamalini, Reham M. Alahmadi, Anis Ahamed, Ashraf Atef Hatamleh, Razack Abdullah and Jeyam Muthusamy

Microbiol. Res. 2023, 14(3), 1264-1278; https://doi.org/10.3390/microbiolres14030085 - 04 Sep 2023

Viewed by 1079

Abstract

Microsporum gypseum is a dermatophyte with a geophilic nature that is found all over the globe. It mainly causes tinea in the scalp, arms, and legs in humans. Squalene epoxidase (SE) is a crucial enzyme in M. gypseum for the biosynthesis of ergosterol. [...] Read more.

Microsporum gypseum is a dermatophyte with a geophilic nature that is found all over the globe. It mainly causes tinea in the scalp, arms, and legs in humans. Squalene epoxidase (SE) is a crucial enzyme in M. gypseum for the biosynthesis of ergosterol. The medicinal plant Balanites aegyptiaca is an abundant supply of secondary constituents with great therapeutic values. In this research, the fruit epicarp portion was used to inhibit M. gypseum using experimental and computational techniques. The anti-dermatophytic activity of epicarp extracts on M. gypseum was evaluated using the poison plate method at five different concentrations. At 3 mg/mL, the M. gypseum was completely controlled by the fractioned chloroform extract of epicarp. The compounds from previous research were utilized for docking studies (Abuthakir et al., 2022). The ideal compounds and the drug terbinafine were then docked using Schrödinger’s Glide module. It demonstrates that (3E)-7-Hydroxy-3,7-dimethyl-3-octen-1-yl-6-O-(6-deoxy-alpha-L-mannopyranosyl)-beta-D-glucopyranoside outperforms other substances and the drug terbinafine in docking analysis. Desmond, Schrödinger Molecular Dynamics simulations were also performed for (3E)-7-Hydroxy-3,7-dimethyl-3-octen-1-yl-6-O-(6-deoxy-alpha-L-mannopyranosyl)-beta-D-glucopyranoside-squalene epoxidase complexes. The complex appears to be more stable, according to the MD simulation research. This study indicates that (3E)-7-Hydroxy-3,7-dimethyl-3-octen-1-yl-6-O-(6-deoxy-alpha-L-mannopyranosyl)-beta-D-glucopyranoside could be used as a potential inhibitor of M. gypseum growth, and it could be studied further. Full article

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12 pages, 947 KiB

Open AccessArticle

Arbuscular Mycorrhizal Fungus Funneliformis mosseae Improves Soybean Growth Even in Soils with Good Nutrition

by Veronika Řezáčová, Ema Némethová, Iva Stehlíková, Alena Czakó and Milan Gryndler

Microbiol. Res. 2023, 14(3), 1252-1263; https://doi.org/10.3390/microbiolres14030084 - 31 Aug 2023

Viewed by 1317

Abstract

Arbuscular mycorrhizal fungi (AMF) improve plant growth and may be useful in maintaining and even restoring soil. However, data on the latter function are sparse and only indirect, which is especially true for conventional management conditions with adequate nutrient availability. Our study focused [...] Read more.

Arbuscular mycorrhizal fungi (AMF) improve plant growth and may be useful in maintaining and even restoring soil. However, data on the latter function are sparse and only indirect, which is especially true for conventional management conditions with adequate nutrient availability. Our study focused on utilizing the prevalent AMF species, Funneliformis mosseae, to enhance Glycine max production, while also exploring its partly explored impact on soil aggregation. Working in greenhouse conditions, we examined whether, in a nutrient-sufficient environment, AMF would improve crop biomass accumulation and nutrition, as well as the stability of soil aggregates (SAS). We also looked for a synergistic effect of dual inoculation using AMF and symbiotic rhizobium. Plants were or were not inoculated with AMF or Bradyrhizobium japonicum in a two-factorial design. AMF inoculation increased soybean biomass, but AMF inoculation had no impact on P and N input to the shoots. Mycorrhiza did not affect either glomalin abundance or SAS. All the impacts were, however, independent from rhizobial inoculation, which was ineffective in this nutrient-available environment. Our assay suggests that arbuscular mycorrhiza may have a positive effect on soybean growth even under conventional management with adequate nutrition. The positive effects of AMF on soybean growth, together with the fact that AMF generally do not thrive in good nutrient availability, should be taken into account when planning mineral fertilization levels. Full article

(This article belongs to the Special Issue Plants, Mycorrhizal Fungi, and Bacteria)

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14 pages, 3737 KiB

Open AccessFeature PaperArticle

Molecular Assessment of MCR-1 Gene among Pandrug-Resistant Acinetobacter baumannii

by Shaimaa S. Sobieh, Shereen A. H. Mohamed, Manal A. El-Sayed and Soad A. Abdallah

Microbiol. Res. 2023, 14(3), 1238-1251; https://doi.org/10.3390/microbiolres14030083 - 30 Aug 2023

Viewed by 1136

Abstract

Background Antimicrobial resistance has become one of the most widespread threats to humans. Acinetobacter baumannii is one of the pathogens responsible for healthcare-associated infections (nosocomial). Colistin is considered the last resort antibiotic against infections with pandrug-resistant (PDR) pathogens. Results: Eleven isolates were detected [...] Read more.

Background Antimicrobial resistance has become one of the most widespread threats to humans. Acinetobacter baumannii is one of the pathogens responsible for healthcare-associated infections (nosocomial). Colistin is considered the last resort antibiotic against infections with pandrug-resistant (PDR) pathogens. Results: Eleven isolates were detected phenotypically as PDR A. baumannii and were confirmed molecularly using 16S rDNA. The MCR-1 gene was not detected within the chromosomal DNA of the selected isolates. Plasmid bearing the MCR-1 gene was identified in 10 selected isolates of A. baumannii that had not been previously observed to carry the MCR-1 gene. Moreover, the use of colistin in combination with anionic antibiotics or natural compound pterostilbene poses a viable therapeutic alternative for PDR and revives colistin’s bactericidal effects on MCR-1-positive A. baumannii. Finally, the transmission electron microscopy studies proved the synergistic effect of these combinations and revealed the disruption of resistant A. baumannii’s outer membrane and alteration of the permeability properties that allowed overcoming the resistance of the isolates to colistin. Conclusions: Antimicrobial resistance of A. baumannii is related to the presence of the transferable plasmid-bearing MCR-1 gene. This study proved the ability of the combinations of colistin with anionic antibiotics and/or natural compound pterostilbene to restore the bactericidal effect of colistin. Overall, these combinations could be novel promising clinical alternatives against the increasing threat of the widespread multidrug-resistant A. baumannii. Full article

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13 pages, 1126 KiB

Open AccessArticle

Lactobacilli Profile in Faecal Samples of Tunisian Children Diagnosed with Autism Spectrum Disorder

by Mariem Chamtouri, Abderrahmen Merghni, Naoufel Gaddour, Maha Mastouri, Silvia Arboleya and Clara G. de los Reyes-Gavilán

Microbiol. Res. 2023, 14(3), 1225-1237; https://doi.org/10.3390/microbiolres14030082 - 24 Aug 2023

Viewed by 1017

Abstract

Alterations in faecal lactobacilli in autistic children have been reported, but little is known related to age and disorder severity. We used a culture-based method and partial 16S rRNA gene sequencing to isolate and identify lactobacilli strains from faeces of Tunisian autistic children [...] Read more.

Alterations in faecal lactobacilli in autistic children have been reported, but little is known related to age and disorder severity. We used a culture-based method and partial 16S rRNA gene sequencing to isolate and identify lactobacilli strains from faeces of Tunisian autistic children (ASD group) and compared them with strains isolated from siblings (SIB) and children from the general population (GP). The ASD group displayed an increased number of different species compared to SIB and GP. Differences in species abundance with age accounted for a significant decrease in the abundance of Lactiplantibacillus plantarum/Lactiplantibacillus pentosus isolates in the GP at the age of 8–10 years compared to the age of 4–7 years, and to a significantly lower abundance of Lacticaseibacillus rhamnosus in the ASD group with respect to SIB and the GP at the age of 8–10 years. Simpson’s and Shannon–Wiener indices showed a more pronounced species diversity increase with age in the GP group compared to the ASD and SIB groups. Minor differences were found in lactobacilli prevalence and in species diversity between children with severe and mild-to-moderate ASD. Overall, we found substantial differences in the profile of faecal lactobacilli species in the ASD and GP groups at the age of 8–10 years. Full article

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Graphical abstract

15 pages, 1899 KiB

Open AccessArticle

Comparative Evaluation of Paclobutrazol and Rhizobacterium Variovorax sp. YNA59 Effects on Mitigating Drought Stress in Chinese Cabbage (Brassica rapa ssp. Pekinensis)

by Sang-Mo Kang, Arjun Adhikari, Yu-Na Kim and In-Jung Lee

Microbiol. Res. 2023, 14(3), 1210-1224; https://doi.org/10.3390/microbiolres14030081 - 24 Aug 2023

Viewed by 1443

Abstract

Drought has severely impacted worldwide agricultural land, resulting in substantial yield loss and abiotic pressures in crops such as Chinese cabbage. Paclobutrazol (PBZ) and plant growth-stimulating bacteria have been extensively recommended to reduce a variety of stresses in crops. Considering these facts, we [...] Read more.

Drought has severely impacted worldwide agricultural land, resulting in substantial yield loss and abiotic pressures in crops such as Chinese cabbage. Paclobutrazol (PBZ) and plant growth-stimulating bacteria have been extensively recommended to reduce a variety of stresses in crops. Considering these facts, we used PBZ and rhizobacterium Variovorax sp. YNA59, a microbe with potential plant growth-stimulating qualities, in Chinese cabbage under drought stress and non-stressed conditions, and we observed their impacts on morphological and physiological attributes. Our findings revealed a considerable improvement in total plant biomass growth after treatment with YNA59 (28%) and PBZ (8%) under drought conditions. In contrast, negative results of PBZ were observed under normal conditions, suppressing plant growth and reducing plant biomass. The increase in physiological parameters, such as chlorophyll content, relative water content, and photochemical efficiencies of PS II, were observed in YNA59-treated plants, followed by PBZ, especially under drought. Furthermore, drought stress significantly increased the endogenous phytohormone abscisic acid level, whereas PBZ and YNA59 inoculations significantly decreased it. Antioxidant analysis revealed that PBZ and YNA increased glutathione and catalase and decreased polyphenol oxidase and peroxidase levels. These findings suggested that rhizobacterium YNA59 could be more significant for conferring water stress in the Chinese cabbage plant than PBZ. Full article

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11 pages, 1224 KiB

Open AccessCommunication

Extracellular Production of Glutathione by Recombinant Escherichia coli K-12

by Hideyuki Suzuki, Kazuki Nishida and Tatsuya Nakamura

Microbiol. Res. 2023, 14(3), 1199-1209; https://doi.org/10.3390/microbiolres14030080 - 23 Aug 2023

Viewed by 1141

Abstract

The goal of this study was to produce a sufficient amount of glutathione in the fermentation medium without the addition of cysteine. This would simplify and reduce the cost of its purification. In addition to reducing the cost of cysteine, it also avoids [...] Read more.

The goal of this study was to produce a sufficient amount of glutathione in the fermentation medium without the addition of cysteine. This would simplify and reduce the cost of its purification. In addition to reducing the cost of cysteine, it also avoids the inhibition of bacterial growth by cysteine. The gshA, gshB, and cysE genes of Escherichia coli were cloned under the control of the strong T5 promoter of the pQE-80L plasmid and introduced into an E. coli strain knocked out for the genes encoding γ-glutamyltranspeptidase and the GsiABCD glutathione transporter, which are responsible for the recycling of excreted glutathione. The overexpression of the gshA and gshB genes, genes for γ-glutamylcysteine synthetase and glutathione synthetase, and the cysE^{V95R D96P} gene, a gene for serine acetyltransferase with the V95R D96P mutation that makes it insensitive to cysteine, were effective on glutathione production. Na₂S₂O₃ was a good sulfur source for glutathione production, while the addition of Na₂SO₄ did not affect the glutathione production. With the addition of 50 mM glutamic acid and 75 mM glycine, but without the addition of cysteine, to the simplified SM1 medium, 4.6 mM and 0.56 mM of the reduced and oxidized glutathione, respectively, were accumulated in the extracellular space after 36 h of batch culture. This can eliminate the need to extract glutathione from the bacterial cells for purification. Full article

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14 pages, 1457 KiB

Open AccessArticle

Construction of Recombinant Escherichia coli with a High L-Phenylalanine Production Yield from Glucose

by Pengfei Gu, Shuo Zhao, Chengwei Li, Shuixing Jiang, Hao Zhou and Qiang Li

Microbiol. Res. 2023, 14(3), 1185-1198; https://doi.org/10.3390/microbiolres14030079 - 21 Aug 2023

Viewed by 1532

Abstract

L-phenylalanine is an important aromatic amino acid that is widely used in the area of feed, food additives, and pharmaceuticals. Among the different strategies of L-phenylalanine synthesis, direct microbial fermentation from raw substrates has attracted more and more attention due to its environment [...] Read more.

L-phenylalanine is an important aromatic amino acid that is widely used in the area of feed, food additives, and pharmaceuticals. Among the different strategies of L-phenylalanine synthesis, direct microbial fermentation from raw substrates has attracted more and more attention due to its environment friendly process and low-cost raw materials. In this study, a rational designed recombinant Escherichia coli was constructed for L-phenylalanine production. Based on wild type E. coli MG1655, multilevel engineering strategies were carried out, such as directing more carbon flux into the L-phenylalanine synthetic pathway, increasing intracellular level of precursors, blocking by-product synthesis pathways and facilitating the secretion of L-phenylalanine. During 5 L fed batch fermentation, recombinant E. coli MPH-3 could produce 19.24 g/L of L-phenylalanine with a yield of 0.279 g/g glucose. To the best of our knowledge, this is one of the highest yields of L-phenylalanine producing E. coli using glucose as the sole carbon source in fed-batch fermentation. Full article

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17 pages, 1828 KiB

Open AccessArticle

Microcystin Concentrations and Detection of the mcyA Gene in Water Collected from Agricultural, Urban, and Recreational Areas in a Karst Aquifer in the Yucatan Peninsula of Mexico

by Gerardo Ávila-Torres, Gabriela Rosiles-González, Victor Hugo Carrillo-Jovel, Gilberto Acosta-González, Eduardo Cejudo-Espinosa, Daniela Ortega-Camacho, Cecilia Hernández-Zepeda and Oscar Alberto Moreno Valenzuela

Microbiol. Res. 2023, 14(3), 1168-1184; https://doi.org/10.3390/microbiolres14030078 - 18 Aug 2023

Cited by 3 | Viewed by 930

Abstract

The eutrophication of freshwater ecosystems allows the proliferation of cyanobacteria that can produce secondary metabolites such as microcystins. The main aim of this study was to explore the occurrence and concentration of microcystin and the mcyA gene in water bodies located in agricultural, [...] Read more.

The eutrophication of freshwater ecosystems allows the proliferation of cyanobacteria that can produce secondary metabolites such as microcystins. The main aim of this study was to explore the occurrence and concentration of microcystin and the mcyA gene in water bodies located in agricultural, urban, and recreational areas in the karst aquifer of the Yucatan peninsula of Mexico (YPM) and to analyze the water quality variables and chlorophyll-a (Chl-a) associated with their presence. Water samples were collected from 14 sites, and microcystin concentrations were quantified using antibody-based ELISA test. Total DNA was isolated from filters and used for PCR amplification of a fragment of the mcyA gene. Amplicons were cloned and sequenced to identify toxin-producing cyanobacteria present in water. Results showed that water bodies had different trophic status based on Carlson’s trophic state index. Dissolved inorganic nitrogen (DIN: NH₄⁺ + NO₃⁻ + NO₂⁻) and P-PO₄³⁻ concentrations were within a range of 0.077–18.305 mg DIN/L and 0.025–2.5 mg P-PO₄³⁻/L, respectively, per sampled site. All sampled sites presented microcystin concentrations within a range of ≥0.14 µg/L to ≥5.0 µg/L, from which 21.4% (3/14) exceeded the limit established in water quality standards for water consumption (1 µg/L). The mcyA gene fragment was detected in 28.5% (4/14) of the sites. A total of 23 sequences were obtained from which 87% (20/23) shared >95% nucleotide identity (nt) with the genus Microcystis and 13% (3/23) shared >87% nt identity with uncultured cyanobacteria. No correlation with the presence of the mcyA gene and microcystins was found; however, a positive correlation was detected between microcystin concentrations with pH and Chl-a. Full article

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18 pages, 1623 KiB

Open AccessArticle

Isolation and Characterization of Lactic Acid Bacteria from Cocoa Mucilage and Meat: Exploring Their Potential as Biopreservatives for Beef

by Laura Morante-Carriel, Fernando Abasolo, Carlos Bastidas-Caldes, Erwin A. Paz, Rodrigo Huaquipán, Rommy Díaz, Marco Valdes, David Cancino, Néstor Sepúlveda and John Quiñones

Microbiol. Res. 2023, 14(3), 1150-1167; https://doi.org/10.3390/microbiolres14030077 - 18 Aug 2023

Viewed by 2217

Abstract

The aim of this study was to characterize lactic acid bacteria (LAB) isolated from cocoa mucilage and beef and evaluate their inhibitory effect in vitro against pathogenic bacteria, as well as determine their effect on beef quality. For the antagonist assay, 11 strains [...] Read more.

The aim of this study was to characterize lactic acid bacteria (LAB) isolated from cocoa mucilage and beef and evaluate their inhibitory effect in vitro against pathogenic bacteria, as well as determine their effect on beef quality. For the antagonist assay, 11 strains of LAB were selected and tested against pathogenic strains of Escherichia coli and Salmonella sp. The pathogenic bacteria were cultured in a medium, and a previously reactivated LAB bacterial pellet was added. After incubation, halos were observed around the bacterial colonies of the pathogenic strains, indicating inhibition by the LAB. It was identified that the LAB strains used belonged to the genus Lactobacillus, and the CCN-5 strain showed high percentages of inhibition against Salmonella sp. (58.33%) and E. coli (59%). The effectiveness of LAB application methods (immersion, injection, and spraying) did not present statistical differences. Furthermore, no significant changes in the physicochemical characteristics of beef were observed after the application of LAB. The results obtained demonstrate the potential of cocoa mucilage, as a biological control agent through LAB application, for beef biopreservation due to its ability to inhibit the growth of pathogenic bacteria. Full article

(This article belongs to the Collection Microbiology and Technology of Fermented Foods)

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11 pages, 3009 KiB

Open AccessArticle

Development of a Novel Emulsion Formulation of Trichoderma asperelloides PSU-P1 Conidia against Stem Canker on Dragon Fruit Caused by Neoscytalidium dimidiatum

by Warin Intana, Prisana Wonglom, Kim Sreang Dy and Anurag Sunpapao

Microbiol. Res. 2023, 14(3), 1139-1149; https://doi.org/10.3390/microbiolres14030076 - 17 Aug 2023

Cited by 1 | Viewed by 1192

Abstract

Stem canker on dragon fruit caused by Neoscytalidium dimidiatum causes severe losses in production of this fruit worldwide. Biological control by Trichoderma species is widely used to control several plant diseases. However, environmental conditions affect the use of biocontrol agents in the field. [...] Read more.

Stem canker on dragon fruit caused by Neoscytalidium dimidiatum causes severe losses in production of this fruit worldwide. Biological control by Trichoderma species is widely used to control several plant diseases. However, environmental conditions affect the use of biocontrol agents in the field. The development of a new formulation may offer an alternative way to address the problem of stem canker on dragon fruit caused by N. dimidiatum. In this study, we sought to develop a Trichoderma asperelloides PSU-P1 formulation that would be effective against N. dimidiatum. Three vegetable oils, two emulsifier-dispersing agents (Tween 20 and Tween 80), and one source of carbon (dextrose) were tested for carrier additives. We assessed the viability and antifungal ability of formulations incubated at ambient temperature and at 10 °C during a storage period of 1–6 months. The formulation composed of coconut oil, DW, and tween 20 in a ratio of 30:60:10 required a mixing time of 1.14 min; this was significantly faster than the mixing times of other formulations. Application of this formulation suppressed canker development; a canker area of 0.53 cm² was recorded, compared with a control (pathogen only) area of 1.65 cm². In terms of viability, this formulation stored at ambient temperature showed a surface area percentage of T. asperelloides PSU-P1 ranging from 64.43 to 75.7%; the corresponding range for the formulation stored at cool temperature was 70.59–75.6%. For both formulations, percentage inhibition gradually decreased from 1 to 6 months, with ranges of 59.21–77% and 60.65–76.19% for formulations incubated at ambient and cool temperatures, respectively. Our findings suggest that the formulation developed in this study prolongs the viability of T. asperelloides PSU-P1 conidia by up to 6 months, effectively inhibits N. dimidiatum in vitro, and reduces stem canker in vivo. Full article

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15 pages, 2315 KiB

Open AccessArticle

Antibacterial, Antibiofilm, and Anti-Inflammatory Activities of Ginger Extract against Helicobacter pylori

by Mahmoud K. M. Elbestawy, Gamal M. El-Sherbiny, Saad A. Moghannem and Eman E. Farghal

Microbiol. Res. 2023, 14(3), 1124-1138; https://doi.org/10.3390/microbiolres14030075 - 16 Aug 2023

Viewed by 3631

Abstract

The increased emergence of multidrug-resistant Helicobacter pylori is related to many health issues. Zingiber officinale (Z. officinale) is a plant usually used in folk medicine to treat a variety of diseases. This study was conducted to evaluate the ability of Z. [...] Read more.

The increased emergence of multidrug-resistant Helicobacter pylori is related to many health issues. Zingiber officinale (Z. officinale) is a plant usually used in folk medicine to treat a variety of diseases. This study was conducted to evaluate the ability of Z. officinale extract to combat resistant H. pylori. The disc diffusion, microdilution, and microplate assays were performed to evaluate the susceptibility to antibiotics and the antibacterial and antibiofilm activities of the Z. officinale extracts. Using the checkerboard method, the combined effects of gentamicin and Z. officinale extract were investigated. In addition, anti-inflammatory activity and GC-MS analysis were performed according to a modified protocol. According to the findings, H. pylori isolates exhibited resistance rates of 56.33, 50.0, and 45.85 against metronidazole, gentamicin, and tetracycline, respectively. The methanolic extract of Z. officinale showed the strongest effectiveness against resistant H. pylori isolates with MICs of 20.0 to 50.0 µg/mL, including both H. pylori isolates and the standard strain NCTC 11637. Z. officinale extract suppresses the biofilm formed by H. pylori isolates with a percentage of 92.96% at 50.0 µg/mL, compared with 97.19% for gentamicin at the same concentration. According to FICI values, the combination of methanolic Z. officinale extract with gentamicin increases bacterial sensitivity to such drugs. Moreover, the Z. officinale extract exhibits strong anti-inflammatory activity, with inhibition of red blood cell membrane stabilization increasing from 49.83% to 61.47% at a concentration of 4 to 32 µg/mL. The GC-MS analysis of Z. officinale extract exhibits 17 different chemical compounds. Besides showing antibacterial properties, the extract also contains the anti-inflammatory compound gingerol as the main constituent, which inhibits the growth of H. pylori and its biofilm and is a promising natural therapeutic alternative or enhances antibiotic activity. Full article

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10 pages, 3094 KiB

Open AccessCommunication

Baicalin Attenuated PANX-1/P2X7 Axis, P2Y6, and NLRP3/Caspase-1 Signaling Pathways in Peritonitis Induced by Glaesserella parasuis

by Shulin Fu, Xinyue Tian, Jingyang Li, Yuzhen Yuan, Xiaoyi Li, Mingxing Ren, Ling Guo, Chun Ye, Bingbing Zong, Yu Liu, Qirong Lu and Yinsheng Qiu

Microbiol. Res. 2023, 14(3), 1114-1123; https://doi.org/10.3390/microbiolres14030074 - 09 Aug 2023

Viewed by 964

Abstract

Glaesserella parasuis (G. parasuis) can cause peritonitis in piglets. However, the pathogenesis of peritonitis remains unclear. Baicalin has been shown to possess anti-inflammatory and anti-oxidant functions. The aim of this study was to investigate the role of the PANX-1/P2X7 axis and [...] Read more.

Glaesserella parasuis (G. parasuis) can cause peritonitis in piglets. However, the pathogenesis of peritonitis remains unclear. Baicalin has been shown to possess anti-inflammatory and anti-oxidant functions. The aim of this study was to investigate the role of the PANX-1/P2X7 axis and the P2Y6 signaling pathway in peritonitis induced by G. parasuis and the effect of baicain on the PANX-1/P2X7 axis and P2Y6 pathway activation triggered by G. parasuis. A G. parasuis serovar 5 isolate SH0165 strain was obtained from the lungs of commercially produced pigs which had the typical symptoms of Glässer’s disease, namely arthritis, fibrinous polyserositis, hemorrhagic pneumonia, and meningitis. Then, 35 piglets were randomly divided into five groups, each group containing seven piglets. The groups consisted of a negative control group, an infection group, a 25 mg/kg baicalin group, a 50 mg/kg baicalin group, and a 100 mg/kg baicalin group. The results showed that G. parasuis could promote PANX-1/P2X7 axis and P2Y6 activation; induce NLRP3/caspase-1, IL-1β and IL-18 expression; trigger PLC/PKC and MLCK/MLC signaling activation; attenuate the expression of tight junction proteins ZO-1, E-cadherin, Occludins, and claudin 1; and stimulate CD14, CD24, CD36, CD47, and CD91 expression in the peritoneum as measured via Western blot (p < 0.01; PLC, p < 0.05). Baicalin could significantly inhibit PANX-1/P2X7 axis, P2Y6, and NLRP3/caspase-1 activation; reduce IL-1β and IL-18 expression; attenuate PLC/PKC and MLCK/MLC activation; promote ZO-1, E-cadherin, occludins, and claudin 1 expression; and reduce CD14, CD24, CD36, CD47, and CD91 expression in the peritoneum induced by G. parasuis as measured via Western blot. Our results deepen the understanding of the mechanism of peritonitis triggered by G. parasuis and provide some novel potential methods of controlling G. parasuis infection. Full article

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25 pages, 2214 KiB

Open AccessReview

Sage and Lavender Essential Oils as Potential Antimicrobial Agents for Foods

by Barbara Speranza, Angela Guerrieri, Angela Racioppo, Antonio Bevilacqua, Daniela Campaniello and Maria Rosaria Corbo

Microbiol. Res. 2023, 14(3), 1089-1113; https://doi.org/10.3390/microbiolres14030073 - 07 Aug 2023

Cited by 4 | Viewed by 3099

Abstract

Modern society is becoming more and more reluctant to use antibiotic or chemical compounds in food production and is demanding foods without what they perceive as artificial and harmful chemicals, including many used as antimicrobials and preservatives in food. Another big problem is [...] Read more.

Modern society is becoming more and more reluctant to use antibiotic or chemical compounds in food production and is demanding foods without what they perceive as artificial and harmful chemicals, including many used as antimicrobials and preservatives in food. Another big problem is the improper use of antibiotics, especially broad-spectrum ones, which has significantly contributed to increased antibiotic resistance in many microorganisms. As a consequence, the whole scientific world has recently concentrated numerous studies on the research of natural remedies capable of counteracting multidrug-resistant strains and fighting infections: the use of aromatic plants and their essential oils (EOs) as potential alternatives to conventional antimicrobials to extend shelf life and combat foodborne pathogens has heightened. Among EOs, sage and lavender have also been promoted for their potential antimicrobial capabilities. In this review, we summarize the latest research studies performed about sage and lavender EOs, focusing on their chemical composition and their biological and antimicrobial properties; the aim is to give an overview of the current knowledge about their major components, effectiveness, mechanisms of action, synergistic effects and use in foods to facilitate a widespread application in both food and pharmaceuticals industries. Full article

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12 pages, 273 KiB

Open AccessArticle

A Comparative Prospective Study in Evaluating Candida spp. In Vitro Susceptibility through Micronaut-AM and Sensititre Yeast-One

by Laura Trovato, Maddalena Calvo, Guido Scalia and Salvatore Oliveri

Microbiol. Res. 2023, 14(3), 1077-1088; https://doi.org/10.3390/microbiolres14030072 - 07 Aug 2023

Cited by 2 | Viewed by 895

Abstract

Background. Among invasive fungal infection pathogens, Candida spp. represent the most common aetiological agents. The increasing rate of severe infections and the emergence of antimicrobial resistance highlight the importance of in vitro susceptibility testing. The EUCAST and the CLSI have established reference microdilutions [...] Read more.

Background. Among invasive fungal infection pathogens, Candida spp. represent the most common aetiological agents. The increasing rate of severe infections and the emergence of antimicrobial resistance highlight the importance of in vitro susceptibility testing. The EUCAST and the CLSI have established reference microdilutions that are reliable but difficult to apply in a laboratory routine. Commercial microdilutions could represent a valuable alternative within a diagnostic workflow. Methods. A number of 50 Candida spp. collected from positive blood samples simultaneously underwent the Sensititre Yeast-One microdilution as a standard susceptibility test and the Micronaut-AM as an experimental method. A comparison between the two techniques was produced, evaluating the effectiveness of the Micronaut-AM compared to the extensively consolidated Sensititre Yeast-One. Results. The two techniques revealed optimal agreement rates, confirming the reliability of the commercial microdilution kits within the diagnostic workflows. The results showed remarkable concordance for both susceptible and resistant isolates, highlighting slight variations in the different identified Candida species. Conclusions. Future studies about antifungal susceptibility testing should be encouraged, including molecular confirmation of possible resistance phenotypes and extended isolate numbers for the different Candida species. Moreover, it would be interesting to plan clinical trials after the execution of the examined commercial microdilution methods. Full article

10 pages, 1494 KiB

Open AccessArticle

Population Knowledge and Practices and the Prevalence of Trypanosomes Circulating in Domestic Animals in Three Active Human African Trypanosomiasis Foci in the Republic of Congo

by Irina Bemba, Arsene Lenga, Herman Parfait Awono-Ambene and Christophe Antonio-Nkondjio

Microbiol. Res. 2023, 14(3), 1067-1076; https://doi.org/10.3390/microbiolres14030071 - 04 Aug 2023

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Abstract

Human African Trypanosomiasis (HAT) is still endemic in the Republic of Congo. Although the incidence of cases has significantly decreased over years, the disease still persists in some active foci. Factors contributing to the maintenance of the disease such as the existence of [...] Read more.

Human African Trypanosomiasis (HAT) is still endemic in the Republic of Congo. Although the incidence of cases has significantly decreased over years, the disease still persists in some active foci. Factors contributing to the maintenance of the disease such as the existence of an animal reservoir or population knowledge are still not well known. It is in this context that a study focusing on the knowledge and practices of the population with regard to HAT as well as on the prevalence of trypanosomes infecting animals was undertaken in three active HAT foci in the Republic of Congo. The study was performed using field surveys conducted from November 2019 to June 2021. Domestic animal blood was examined by microscopy and PCR to detect the presence of trypanosomes. A structured questionnaire was administered to the population to assess their knowledge and practices concerning HAT in these endemic foci. More than half of the animals examined were found to be infected with trypanosomes (51.22%). The main trypanosome species infecting animals were Trypanosoma congolense savannah (67.2%) and Trypanosoma brucei (s.l.) (32.8%). No trypanosomes infecting humans were detected. Concerning household surveys, more than half of the respondents (52.9%) were fully aware of the mode of transmission and symptoms of the disease. The majority of people preferred to wear clothes covering the whole body and to use locally made soap as repellents to protect themselves from tsetse fly bites. This study suggests frequent circulation of animal trypanosomes in domestic animals and the use of personal measures to protect against tsetse fly bites. Updating information on the HAT animal reservoir and population knowledge alongside regular monitoring of the tsetse fly populations and the use of traps to control tsetse flies are crucial to drive efforts towards the elimination of gHAT in the Republic of Congo. Full article

(This article belongs to the Collection Public Health and Quality Aspects Related to Animal Productions)

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Microbiol. Res., Volume 14, Issue 3 (September 2023) – 43 articles

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