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Appl. Microbiol., Volume 3, Issue 2 (June 2023) – 20 articles

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12 pages, 513 KiB  
Article
Sublethal Exposure to Common Benzalkonium Chloride Leads to Antimicrobial Tolerance and Antibiotic Cross-Resistance in Commensal and Opportunistic Bacterial Species
by Sheareazade A. Pena, Juana G. Salas, Nilisha Gautam, Ashley M. Ramos and Aubrey L. Frantz
Appl. Microbiol. 2023, 3(2), 580-591; https://doi.org/10.3390/applmicrobiol3020041 - 18 Jun 2023
Cited by 1 | Viewed by 2388
Abstract
The production and consumer use of disinfectants has substantially increased during the COVID-19 pandemic. Benzalkonium chloride (BAC) is a mixture of alkyl benzyl dimethyl ammonium chloride compounds and is the most common active ingredient in surface cleaning and disinfecting products. Accordingly, BAC compounds [...] Read more.
The production and consumer use of disinfectants has substantially increased during the COVID-19 pandemic. Benzalkonium chloride (BAC) is a mixture of alkyl benzyl dimethyl ammonium chloride compounds and is the most common active ingredient in surface cleaning and disinfecting products. Accordingly, BAC compounds are routinely in contact with microorganisms in indoor environments, which may contribute to the development of antimicrobial tolerance and cross-resistance. To investigate the impact of BAC exposure on commensal and opportunistic bacteria of public health importance, we exposed Staphylococcus epidermidis, Corynebacterium xerosis, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa to a standard BAC mixture (BAC12–14), as well as purified BAC16. Minimum inhibitory concentrations (MICs) and antibiotic susceptibilities were determined before and after repeated exposure to sublethal BAC concentrations. MICs for Gram-negative bacteria were significantly higher than Gram-positive bacteria. Additionally, BAC12–14 MICs were significantly higher for opportunistic pathogens and BAC-tolerance was associated with antibiotic cross-resistance. These results suggest that common Gram-negative opportunistic pathogens are less sensitive to BAC-inhibition than commensal species and may preferentially develop antimicrobial tolerance upon repeated or prolonged exposure to BAC12–14. Reevaluating the formulation and concentration of BAC-containing products in efforts to limit the development of antimicrobial tolerance and antibiotic co-resistance is warranted. Full article
(This article belongs to the Topic Antimicrobial Resistance in the Time of COVID-19)
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18 pages, 1086 KiB  
Article
Antioxidant, Antimicrobial and Cosmeceutical Potential of Wild Mushroom Extracts
by Tânia Martins, Liliana Machado-Carvalho, Alfredo Aires, Maria José Saavedra and Guilhermina Marques
Appl. Microbiol. 2023, 3(2), 562-579; https://doi.org/10.3390/applmicrobiol3020040 - 15 Jun 2023
Cited by 1 | Viewed by 1497
Abstract
Macrofungi have been previously studied for their nutritional value and medicinal properties. However, despite wild mushrooms being a great source of beneficial bioactive compounds, the literature exploring their biotechnological application as nutraceuticals, cosmeceuticals and nutricosmetics is scarce. In this work, the species Butyriboletus [...] Read more.
Macrofungi have been previously studied for their nutritional value and medicinal properties. However, despite wild mushrooms being a great source of beneficial bioactive compounds, the literature exploring their biotechnological application as nutraceuticals, cosmeceuticals and nutricosmetics is scarce. In this work, the species Butyriboletus regius, Ganoderma lucidum, Inonotus hispidus, Lanmaoa fragrans, Pisolithus tinctorius, Suillellus luridus, Suillellus mendax and Xerocomus subtomentosus were characterized according to their phenolic composition, antioxidant capacity, antimicrobial activity and cosmeceutical potential. For that purpose, dried and ground mushrooms were extracted with ethanol (40% v/v) using ultrasound-assisted extraction. Of the eight mushrooms analyzed, I. hispidus and P. tinctorius stood out for their high content of phenolic compounds, high antioxidant capacity and anti-hyaluronidase activity. Regarding antimicrobial activity, both mushrooms showed good inhibition of bacterial growth and bactericidal activity, especially on Gram-positive bacteria; however, L. fragans obtained the best results. Cream formulations with I. hispidus and P. tinctorius extracts in their composition improved their antioxidant activity. These results indicate that I. hispidus and P. tinctorius can be proposed as a new potential source of natural compounds with application in the cosmetic industry. Full article
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13 pages, 286 KiB  
Article
Comparative Effectiveness and Persistence of Antimicrobial Durability in Dry and Wet States of a Novel Antimicrobial Surface Disinfectant
by Bahgat Gerges, Joel Rosenblatt, Ying Jiang and Issam Raad
Appl. Microbiol. 2023, 3(2), 549-561; https://doi.org/10.3390/applmicrobiol3020039 - 06 Jun 2023
Viewed by 823
Abstract
Aims: We evaluated a novel disinfectant (VR) and seven comparators (disinfectants A–G) against resistant pathogens common in healthcare settings. Methods and Results: VR at different dilutions, along with commercial disinfectants A–G, was tested against surrogate viruses, and resistant bacterial and fungal pathogens. Surrogate [...] Read more.
Aims: We evaluated a novel disinfectant (VR) and seven comparators (disinfectants A–G) against resistant pathogens common in healthcare settings. Methods and Results: VR at different dilutions, along with commercial disinfectants A–G, was tested against surrogate viruses, and resistant bacterial and fungal pathogens. Surrogate viruses had an initial concentration of ~1 × 108 mL−1, and bacterial and fungal isolates had an initial concentration of ~1 × 106 mL−1 on Siliconee surfaces. After the application of VR or a comparator disinfectant, surfaces were tested for the reduction in microbial loads after 30 s and 5 min wet exposures, and after a 24 h dry residue exposure. Sterile deionized water was used as a control. The VR at a concentration of 4.68% was superior to all comparator disinfectants against most pathogens in wet and dry testing. The VR at 7.8% concentration showed the highest pathogen-reduction rate among all comparator disinfectants when tested against all pathogens. Conclusions: Overall, the novel VR disinfectant was the most effective disinfectant in both wet and dry residue states against the range of tested pathogens. Significance and Impact of the Study: VR is a broadly effective disinfectant combination for use in high-risk settings, particularly those in which intervals between applications of disinfectant can be lengthy or inconsistent. Full article
13 pages, 322 KiB  
Review
Probiotic-Based Sanitation in the Built Environment—An Alternative to Chemical Disinfectants
by Ashley M. Ramos and Aubrey L. Frantz
Appl. Microbiol. 2023, 3(2), 536-548; https://doi.org/10.3390/applmicrobiol3020038 - 06 Jun 2023
Cited by 1 | Viewed by 1860
Abstract
The use of conventional chemical disinfectants is a common practice in built environments and has drastically increased in response to the COVID-19 pandemic. While effective for instantaneous disinfection, the application of chemical disinfectants to indoor surfaces is associated with recontamination and is prone [...] Read more.
The use of conventional chemical disinfectants is a common practice in built environments and has drastically increased in response to the COVID-19 pandemic. While effective for instantaneous disinfection, the application of chemical disinfectants to indoor surfaces is associated with recontamination and is prone to select for antimicrobial-resistant pathogens. In contrast, probiotic-based sanitation (PBS) relies on the premise that probiotic bacteria, namely apathogenic Bacillus spp., when combined with eco-friendly detergents and applied to indoor surfaces can outcompete and exclude pathogens. Recent in situ studies assessing PBS in healthcare settings have demonstrated overwhelmingly positive results, including significant reductions in pathogen burden, antimicrobial-resistant genes and nosocomial infections, yet these studies are limited in duration and scope. Here, we review results of Bacillus-based PBS in practice, identify knowledge gaps and discuss the considerations for the widespread use of PBS in built environments. In a time when indoor cleaning and disinfection has come to the forefront, PBS may offer an attractive, effective and sustainable alternative to conventional chemical disinfectants. Full article
(This article belongs to the Topic Antimicrobial Resistance in the Time of COVID-19)
17 pages, 3978 KiB  
Article
Probiotic Lactic Acid Bacteria for Vaginal Application. Optimization of Biomass Production and Freeze-Drying Conditions
by Antonella Marchesi and María Elena Fátima Nader-Macías
Appl. Microbiol. 2023, 3(2), 519-535; https://doi.org/10.3390/applmicrobiol3020037 - 02 Jun 2023
Viewed by 1316
Abstract
Probiotic formula for the vaginal tract must contain high numbers of viable beneficial bacteria that maintain their characteristics during the production and further storage, in order to exert the claimed probiotic effect. Four probiotic strains—Lactobacillus gasseri CRL1320, Limosilactobacillus reuteri CRL1324, Ligilactobacillus salivarius [...] Read more.
Probiotic formula for the vaginal tract must contain high numbers of viable beneficial bacteria that maintain their characteristics during the production and further storage, in order to exert the claimed probiotic effect. Four probiotic strains—Lactobacillus gasseri CRL1320, Limosilactobacillus reuteri CRL1324, Ligilactobacillus salivarius CRL1328 and Lacticaseibacillus rhamnosus CRL1332—originally isolated from vagina of healthy women exhibiting beneficial properties were evaluated. Therefore, the optimization of growth parameters and dry biomass production with high viability while preserving probiotic features of strains is a great challenge. Different growth conditions in MRS medium were set up in a laboratory bioreactor; two initial pH and agitation were recorded speeds during static or controlled fermentations. Production conditions of 37 °C with controlled pH 6.5 and 5.5-MRS with 150 and 75 rpm stirring speeds were used for CRL1329 and CRL1332 strains, respectively, while static and free pH MRS for CRL1324 and CRL1328 probiotics allowed us to obtain maximal cell viability counts. However, during 12 h of fermentation, biomass yields of 19.3, 16.2 and 15.2 g/L were achieved when CRL1329, CRL1328 and CRL1324 probiotic strains were grown in static and free pH MRS. The highest biomass yield for CRL1332 strain was produced under controlled MRS-initial pH 6.5 and 75 rpm fermentation conditions. To preserve probiotic high biomass viability, freeze-drying was carried out in the presence of different cryoprotective agents. Thus, the highest viable numbers (10.9–11.8 log CFU/g) with survival rates between 91.3 and 95.6% were attained in the presence of 10% trehalose (L. reuteri and L. salivarius), lactose (L. rhammosus) and lactose + trehalose + sucrose mix (L. gasseri). When stability during post-freeze-drying storage was evaluated, probiotic strains showed a remarkably higher viability recovery when stored at 4 °C than at 25 °C for 12 and 3 months, respectively. In addition, surface characteristics of vaginal probiotics were affected to different extents during storage depending on the strain, protective agent and storage time/temperature. Critical factors for growth conditions, drying process and storage stability of probiotic lactobacilli strains were optimized in view to preserve cell high viability and surface features for the design of vaginal probiotic formula. Full article
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15 pages, 2167 KiB  
Article
Spatial Variation of Tetracycline-Resistant E. coli and Relationships with Water Quality Variables in Irrigation Water: A Pilot Study
by Matthew Stocker, Jaclyn Smith and Yakov Pachepsky
Appl. Microbiol. 2023, 3(2), 504-518; https://doi.org/10.3390/applmicrobiol3020036 - 30 May 2023
Cited by 2 | Viewed by 1179
Abstract
Irrigation waters may facilitate the spread of antibiotic-resistant bacteria or genes to humans and animals. Monitoring of resistance in irrigated waters has become common; however, many studies do not incorporate a spatial component into sampling designs. The objective of this work was to [...] Read more.
Irrigation waters may facilitate the spread of antibiotic-resistant bacteria or genes to humans and animals. Monitoring of resistance in irrigated waters has become common; however, many studies do not incorporate a spatial component into sampling designs. The objective of this work was to assess spatiotemporal variations in tetracycline-resistant E. coli in an irrigation pond. Water samples were collected at 10 locations and two different water depths, and in situ and laboratory water quality measurements were performed. The percentage of E. coli resistant to the low (4 μg mL−1) and high (16 μg mL−1) tetracycline doses varied by date and location but were observed to be as high as 12.7% and 6.3% of the total population throughout the study, respectively. While significant differences were not observed between resistance levels measured at different depths, on one date resistant E. coli were only detected in samples collected at depth. Nitrate, fluorescent dissolved organic matter, and dissolved oxygen concentrations were found to be the leading control variables for the percentage of resistant E. coli. This work demonstrates that there may be substantial spatial variability in concentrations of antibiotic-resistant E. coli in irrigation ponds which should be accounted for in the design of monitoring programs. Full article
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11 pages, 1755 KiB  
Article
Comparison of Different Carbon Sources on Biomethane Production with Clostridium cellulovorans and Methanogens
by Haruki Sawada, Hisao Tomita, Fumiyoshi Okazaki and Yutaka Tamaru
Appl. Microbiol. 2023, 3(2), 493-503; https://doi.org/10.3390/applmicrobiol3020035 - 25 May 2023
Cited by 1 | Viewed by 1298
Abstract
Methane (CH4) has attracted attention as not only one of the hydrogen carriers in terms of energy density, but also synthetic natural gas. In nature, the decomposition of organic compounds is performed with bacterial ecosystems that can produce CH4. [...] Read more.
Methane (CH4) has attracted attention as not only one of the hydrogen carriers in terms of energy density, but also synthetic natural gas. In nature, the decomposition of organic compounds is performed with bacterial ecosystems that can produce CH4. Clostridium cellulovorans as a decomposer was cultivated with pig manure (PM) as an unused biomass in this study. As a result of high-performance liquid chromatography (HPLC) analysis, while formate and lactate were decreased in the C. cellulovorans medium containing 0.5% PM, acetate and butyrate were increased in it. Accordingly, in order to compare with the effect of carbon sources for methane production, the cocultivation of C. cellulovorans and the methanogenesis of Methanosarcina mazei or microbial flora of methane production (MFMP) was carried out in the C. cellulovorans medium. As a result, only the cocultivation with C. cellulovorans and MFMP showed methane production in 0.5% acetate medium. Moreover, in comparison with a carbon source in either 1% acetate or 1% methanol medium, MFMP was only cultivated after being precultivated with 0.5% glucose medium for 12 h. The results revealed that MFMP with a 1% methanol medium produced methane approximately eight times higher than with 1% acetate medium. After cultivation with 1% acetate or 1% methanol, next-generation sequencing (NGS) analysis of MFMP was carried out. Interestingly, Methanofollis (0.211%), belonging to methanogens through the CO2 reduction pathway, was dominant in the 1% acetate medium for 72 h cultivation, while Methanosarcina siciliae (1.178%), M. barkeri (0.571%), and Methanofollis (0.490%) were major species in 1% methanol medium for 72 h cultivation. Since Methanosarcina spp. belong to acetoclasts (acetoclastic pathway), methanol could promote the growth of Methanosarcina spp., rather than acetate. Therefore, it seems that Methanosarcina spp. may play a key methanogenesis role in MFMP. Thus, these results will provide important information for low-cost biomethane production. Full article
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8 pages, 1756 KiB  
Communication
Skin Microbiota of Salmonids: A Procedure to Examine Active Bacterial Populations Using an RNA-Based Approach
by Alda Pardo, Alejandro Villasante and Jaime Romero
Appl. Microbiol. 2023, 3(2), 485-492; https://doi.org/10.3390/applmicrobiol3020034 - 18 May 2023
Cited by 1 | Viewed by 1116
Abstract
Fish microbiota studies have mostly addressed intestinal bacterial communities because of their role in fish physiology; however, the skin microbiota has been studied less despite its role as the first pathogen barrier in the host. DNA-based molecular techniques have contributed to improving our [...] Read more.
Fish microbiota studies have mostly addressed intestinal bacterial communities because of their role in fish physiology; however, the skin microbiota has been studied less despite its role as the first pathogen barrier in the host. DNA-based molecular techniques have contributed to improving our understanding of the skin microbiota, but this approach faces challenges, such as the low count of bacteria in healthy fish skin. To overcome this limitation, an RNA-based approach was developed to study the skin microbiota in salmonids, including tissue sampling, RNA extraction, and downstream procedures to obtain PCR amplicons for next-generation sequencing. The protocol originated in this work overcomes the limitations of low bacterial counts and is useful for describing active microbiota in fish skin. The application of the protocol to salmonids reared in both an experimental setting and on a farm revealed that the trout skin microbiota was dominated by bacteria from the phylum Proteobacteria (>65%). At the genus level, Piscirickettsia (46%) was highlighted as the most abundant in the experimental unit samples; in contrast, Pseudoalteromonas (26%), followed by Escherichia_Shigella (~25%), was the most abundant in farmed trout. Full article
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9 pages, 1246 KiB  
Brief Report
A Brief Snapshot of Aspergillus Section Nigri Isolated from Brazilian Peanuts and Soil
by Fernanda Rodrigues, Josué J. Silva, Beatriz T. Iamanaka, Ligia M. Martins and Marta H. Taniwaki
Appl. Microbiol. 2023, 3(2), 476-484; https://doi.org/10.3390/applmicrobiol3020033 - 17 May 2023
Viewed by 1002
Abstract
The occurrence of mycotoxigenic species in peanuts is a major concern, and has been investigated in depth for many years. However, most studies focus on the occurrence of aflatoxigenic fungi, such as Aspergillus section Flavi. The present study aimed to clarify the [...] Read more.
The occurrence of mycotoxigenic species in peanuts is a major concern, and has been investigated in depth for many years. However, most studies focus on the occurrence of aflatoxigenic fungi, such as Aspergillus section Flavi. The present study aimed to clarify the occurrence of Aspergillus section Nigri, a group that harbors species capable of producing ochratoxin A (OTA), which has scarcely been investigated in peanuts. A total of 52 peanut samples, collected in the field and from storage, were analyzed. Aspergillus section Nigri was isolated from 64% and 100% of field and storage samples, respectively, and 218 strains were obtained. Based on the multiloci phylogeny of the CaM and BenA loci, six species of Aspergillus section Nigri were identified: A. brasiliensis, A. niger, A. neoniger, A. welwitschiae, A. costaricaensis, and A. japonicus. The incidence of ochratoxigenic strains was 5.0% (11/218), and only A. niger and A. welwitschiae were able to produce OTA. The presence of OTA in peanuts was found in 6 field and 8 storage samples, with levels ranging from 0.106 to 0.387 and 0.090 to 0.160 µg/kg, respectively. Full article
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11 pages, 483 KiB  
Review
Psychobiotics as an Intervention in the Treatment of Irritable Bowel Syndrome: A Systematic Review
by Weronika Gwioździk, Paulina Helisz, Mateusz Grajek and Karolina Krupa-Kotara
Appl. Microbiol. 2023, 3(2), 465-475; https://doi.org/10.3390/applmicrobiol3020032 - 15 May 2023
Cited by 2 | Viewed by 1585
Abstract
Today’s perceived excess of work versus rest and excessive stressful situations are one of the potential factors for an increasing number of gastrointestinal disorders. Although the prevalence of irritable bowel syndrome (IBS) varies widely, it is assumed that up to 15% of the [...] Read more.
Today’s perceived excess of work versus rest and excessive stressful situations are one of the potential factors for an increasing number of gastrointestinal disorders. Although the prevalence of irritable bowel syndrome (IBS) varies widely, it is assumed that up to 15% of the general population may be affected. Symptoms resulting from IBS take the form of pain, including difficulties with bowel movements, bloating, and a feeling of overflowing in the intestines. These symptoms have a negative impact on patients’ quality of life, so any possible intervention supported by Evidence-Based Medicine should effectively contribute to their improvement. In the following review, the authors compile the current knowledge based on the findings of researchers from around the world. The topic of probiotic therapy is increasingly discussed in the field of lower gastrointestinal disorders, and thus the authors discover links between probiotic strains and the improvement of health quality in patients with IBS, taking into consideration the ways it affects patients’ mental health. As a result, a systematic review was prepared based on 60 items of recent literature, of which more than 80% were published in the last 5 years. Full article
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17 pages, 2254 KiB  
Article
Limnospira indica PCC8005 and Lacticaseibacillus rhamnosus GG Mixed Dietary Combination Reduces Pelvic Irradiation-Induced Symptoms in Mice
by Sarah-Renée Gholam, Charlotte Segers, Mohamed Mysara, Amelie Coolkens, Sarah Baatout, Natalie Leys and Felice Mastroleo
Appl. Microbiol. 2023, 3(2), 448-464; https://doi.org/10.3390/applmicrobiol3020031 - 11 May 2023
Viewed by 1261
Abstract
Throughout their cancer treatments, around half of all patients will undergo irradiation that is accompanied by several side effects reducing their quality of life and leading to the interruption or extension of their treatment course. Pelvic irradiation leads to the triggering of mucositis [...] Read more.
Throughout their cancer treatments, around half of all patients will undergo irradiation that is accompanied by several side effects reducing their quality of life and leading to the interruption or extension of their treatment course. Pelvic irradiation leads to the triggering of mucositis and dysbiosis, further impairing the daily life of the patients. In this work, we address the ability of Limnospira indica strain PCC 8005 and Lacticaseibacillus rhamnosus GG ATCC 53103 in alleviating the above-mentioned side effects triggered by the local pelvic irradiation of 12 Gy in a mouse model. We found that the combinatorial administration of these food supplements was able to confer partial tight junction protection while the bacterial translocation towards the mesenteric lymph nodes was found to be identical between the saline sham-irradiated and supplemented irradiated group. Furthermore, the supplemented group did not present a significant shift in microbial composition following pelvic irradiation, indicating that the bacterial formulation was able to mitigate the dysbiosis induced by the latter treatment, as observed in the saline irradiated group. These very promising results will be further completed by investigating the mode of action and/or active molecules mediating the beneficial effects of both L. indica PCC 8005 and L. rhamnosus GG. Full article
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19 pages, 1158 KiB  
Review
The Role of an Altered Gut Microbiome in Parkinson’s Disease: A Narrative Review
by Sara Hashish and Mohamed Salama
Appl. Microbiol. 2023, 3(2), 429-447; https://doi.org/10.3390/applmicrobiol3020030 - 10 May 2023
Cited by 4 | Viewed by 2853
Abstract
Parkinson’s disease is a debilitating multisystemic disorder affecting both the central and peripheral nervous systems. Accumulating evidence suggests a potential interaction between gut microbiota and the pathophysiology of the disease. As a result of the degradation of dopaminergic neurons, PD patients develop motor [...] Read more.
Parkinson’s disease is a debilitating multisystemic disorder affecting both the central and peripheral nervous systems. Accumulating evidence suggests a potential interaction between gut microbiota and the pathophysiology of the disease. As a result of the degradation of dopaminergic neurons, PD patients develop motor impairments such as tremors, rigidity, and slowness of movement. These motor features are preceded by gastrointestinal issues, including constipation. Given these gastrointestinal issues, the gut has emerged as a potential modulator of the neurodegenerative cascade of PD. Several studies have been carried out to broaden our understanding of the gut–microbiota–brain axis in PD. As a result, a decrease in short-chain fatty acid synthesizing bacteria has been observed in multiple studies. Some studies, on the other hand, have shown an enrichment of mucin- and levodopa-degrading microbes. In this review, we compiled the available evidence from the literature on the bidirectional communication between the gut microbiome system and the brain in PD. We also addressed the association between dysbiosis and the clinical symptoms of PD and host–drug metabolism. Finally, we touched on some of the therapeutic interventions that may restore eubiosis and modulate the gut structure to restrain disease progression. Full article
(This article belongs to the Special Issue Human Microbiota Influence on Human Health Status 2.0)
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12 pages, 925 KiB  
Article
Molecular Identification of Blastocystis hominis Isolates in Patients with Autoimmune Diseases
by Ahmed M. Mahmoud, Khadiga A. Ismail, Osama M. Khalifa, Maha M. Abdel-wahab, Howaida M. Hagag and Mahmoud K. Mahmoud
Appl. Microbiol. 2023, 3(2), 417-428; https://doi.org/10.3390/applmicrobiol3020029 - 06 May 2023
Cited by 2 | Viewed by 1905
Abstract
Background: Blastocystis hominis (B. hominis) is a ubiquitous parasite that has spread worldwide and is commonly present in human stool specimens. It was hypothesized that infection with B. hominis plays a role in the pathogenesis of autoimmune diseases in humans. The [...] Read more.
Background: Blastocystis hominis (B. hominis) is a ubiquitous parasite that has spread worldwide and is commonly present in human stool specimens. It was hypothesized that infection with B. hominis plays a role in the pathogenesis of autoimmune diseases in humans. The aim of this study is to test this hypothesis by investigating patients with autoimmune diseases. Patients with various types of autoimmune diseases with gastrointestinal symptoms were enrolled in this study as cases (n = 72) along with nongastrointestinal symptom patients as controls (n = 58). All participants in this study were subjected to history taking and were investigated for B. hominis infection via wet-mount microscopic stool examinations, staining with trichrome stain, and molecular-based tests applied to their fecal samples. Blood samples were also tested for complete blood counts. B. hominis were identified with specific PCR more in cases (12/72; 16.6%) than in controls (3/58; 5.2%), with a significant difference (p < 0.05). Significant decreases in white blood cell counts were demonstrated in systemic lupus erythematosus (SLE) and ulcerative colitis (UC) patients infected with B. hominis when compared to patients with nongastrointestinal symptoms (p-value < 0.05). Full article
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17 pages, 1027 KiB  
Review
Phycoremediation Processes for Secondary Effluent from Sewage Treatment Plants Using Photosynthetic Microorganisms: A Review
by Lina Susana Pérez-Mora, Lauris del Carmen Mejia-da-Silva, Eleane de Almeida Cezare-Gomes, Évellin do Espirito Santo, Aline Kirie Gohara-Beirigo, Marcelo Chuei Matsudo, Bruno Monteiro Nardin, Célia Leite Sant’Anna and João Carlos Monteiro de Carvalho
Appl. Microbiol. 2023, 3(2), 400-416; https://doi.org/10.3390/applmicrobiol3020028 - 28 Apr 2023
Cited by 2 | Viewed by 1984
Abstract
Taking into account the worrying scenario of water scarcity, it is essential to enable more efficient technologies for wastewater treatment. Wastewater may be treated by conventional biological processes that remove pathogenic organisms, particulate and soluble organic compounds, and other components. However, secondary effluents [...] Read more.
Taking into account the worrying scenario of water scarcity, it is essential to enable more efficient technologies for wastewater treatment. Wastewater may be treated by conventional biological processes that remove pathogenic organisms, particulate and soluble organic compounds, and other components. However, secondary effluents from treatment plants may still contain toxic elements or high concentrations of inorganic nutrients (mainly nitrogen and phosphorus), which enable the growth of photosynthetic microorganisms in water bodies, resulting in eutrophication. In this context, cultivation of photosynthetic microorganisms in secondary wastewater from sewage treatment allows the removal of nutrients from such wastewater, reducing the possibility of eutrophication. Moreover, microalgal biomass, produced in this tertiary wastewater treatment, may be harvested by different methods with the potential for different applications, such as fertilizer and biofuel. Full article
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12 pages, 2424 KiB  
Article
Survival Time, Mortality Rate, and Feeding Damage of Adult Myllocerus undecimpustulatus undatus (Coleoptera: Curculionidae) Exposed to Biopesticides in Laboratory Bioassays
by Anita S. Neal, Pasco B. Avery and Ronald D. Cave
Appl. Microbiol. 2023, 3(2), 388-399; https://doi.org/10.3390/applmicrobiol3020027 - 25 Apr 2023
Viewed by 1198
Abstract
Survival time, percentage mortality, and feeding behavior were evaluated for adults of the weevil Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae) exposed to biopesticides by using a Petri dish plant-based bioassay system. Treatments consisted of three registered entomopathogenic fungal formulations (BotaniGard ES, PFR-97 20% [...] Read more.
Survival time, percentage mortality, and feeding behavior were evaluated for adults of the weevil Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae) exposed to biopesticides by using a Petri dish plant-based bioassay system. Treatments consisted of three registered entomopathogenic fungal formulations (BotaniGard ES, PFR-97 20% WDG, and Met52 EC) and three biochemical formulations (AzaMax, Entrust, and PyGanic EC); a synthetic chemical insecticide (Sevin SL) and distilled water served as control treatments. Thirty adult M. undecimpustulatus undatus (ten per bioassay cage replicate, three replicates per treatment) were given cocoplum leaves sprayed to the point of runoff with a treatment. Survivorship of weevils was checked daily for 15 days. Five trials (15 total replicates per treatment) were performed. Survival times of weevils in all product treatments were shorter than those of weevils in the water control treatment. Percentages of beetle mortality in the Entrust and BotaniGard treatments were about two-fold higher than in the other treatments. Mean percentages of mycosis for beetles in the BotaniGard, PFR-97, and Met 52 treatments were 90%, 8%, and 5%, respectively. Weevils that consumed BotaniGard-treated leaves caused significantly more leaf damage than weevils that consumed leaves with PFR-97 or Met52. Weevils on leaves treated with Entrust, PyGanic, AzaMax, and Sevin consumed significantly less than those in the fungal and water only treatments. The high mortality rates caused by Entrust and BotaniGard suggest that populations of adult M. undecimpustulatus undatus might be well-managed using these two commercially available biopesticides. Additional testing is needed in the field to corroborate our results obtained under controlled laboratory conditions. Full article
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13 pages, 4601 KiB  
Article
Construction of an Escherichia coli Strain Capable of Utilizing Steamed Rice as the Sole Carbon and Energy Source by Extracellular Expression of Amylase and Its Use for the Production of Putrescine
by Hideyuki Suzuki, Nana Iwamoto and Manami Nishimura
Appl. Microbiol. 2023, 3(2), 375-387; https://doi.org/10.3390/applmicrobiol3020026 - 24 Apr 2023
Viewed by 2041
Abstract
The amyE gene encoding α-amylase from Bacillus subtilis 168 was fused to several genes, the products of which are membrane proteins to express AmyE extracellularly. Genes of CapA, a subunit of the capsular poly-γ-glutamate synthetase of Bacillus subtilis subsp. natto; YiaTR232 [...] Read more.
The amyE gene encoding α-amylase from Bacillus subtilis 168 was fused to several genes, the products of which are membrane proteins to express AmyE extracellularly. Genes of CapA, a subunit of the capsular poly-γ-glutamate synthetase of Bacillus subtilis subsp. natto; YiaTR232, the first 232 residues of YiaT, an outer membrane protein of Escherichia coli K-12; and PgsA, cytidine 5′-diphosphate-diacylglycerol-glycerol-3-phosphate 3-phosphatidyltransferase of B. subtilis subsp. natto, were used. The Escherichia coli strain harboring the plasmid carrying the pgsA-amyE fusion expressed a very high level of amylase not only on the extracellular surface of the cells but also in the medium and the intracellular space and solubilized steamed rice in two days. The N-terminal amino acid sequence of the amylase purified from the culture medium (Ser-Ala-Glu-Thr-Ala) indicated that it was cleaved at the signal peptide cleavage site of AmyE. The strain SH2204, transformed with pKN11 carrying speA (arginine decarboxylase gene), speB (agmatinase gene) and argAATG Y19C (N-acetylglutamate synthase gene) and pMAN63 carrying pgsA-amyE produced 1.2 mM putrescine from 5 mM arginine by adding 0.5 mM IPTG in eight days. Discarding steamed rice is not only a food loss, but also a waste of renewable, biogenerated resources due to the burning of it with petroleum, increasing carbon dioxide in the atmosphere. The E. coli strain developed in this study can help solve this problem because it can produce an important chemical using steamed rice as the sole carbon and energy source. Full article
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17 pages, 1686 KiB  
Article
Impacts of Tillage Practices on Growth, Phosphorus Uptake, and Yield of Maize in Controlled and Field-Based Studies in Relation to Arbuscular Mycorrhizal Fungi
by Yuya Tatewaki, Masao Higo and Katsunori Isobe
Appl. Microbiol. 2023, 3(2), 358-374; https://doi.org/10.3390/applmicrobiol3020025 - 22 Apr 2023
Cited by 1 | Viewed by 1507
Abstract
This study investigated the effects of arbuscular mycorrhizal fungi (AMF) on the growth, phosphorus (P) uptake, and yield of maize in the presence or absence of tillage. The two-year field experiment was conducted in Kanagawa, Japan. Firstly, we investigated whether the presence of [...] Read more.
This study investigated the effects of arbuscular mycorrhizal fungi (AMF) on the growth, phosphorus (P) uptake, and yield of maize in the presence or absence of tillage. The two-year field experiment was conducted in Kanagawa, Japan. Firstly, we investigated whether the presence of indigenous AMF communities in the roots, as determined by amplicon sequencing analysis, contributed to maize growth in Experiment 1, a 2-year field-based study. The findings revealed that the maize (Zea mays L.) in rotary tillage had higher P uptake, growth at the six-leaves collar stage, and yield, compared to no tillage. The AMF communities colonizing maize roots were altered by the presence or absence of tillage; specifically, tillage increased the dominance of the Gigasporaceae, whereas no tillage increased the dominance of the Acaulosporaceae. Based on these findings, we confirmed whether the inoculation of similar AMF strains, as analyzed in the field study of tillage practices on maize roots, produces growth-promoting effects for maize growth in a controlled pot experiment consistent with the results of the field experiment. For experiment 2, Dentiscutata cerradensis TK-1, Cetraspora pellucida SZ-3 (Gigasporaceae), Acaulospora morrowiae AP-5, and A. longula F-1 (Acaulosporaceae) were inoculated as AMF inocula for a pot experiment. The results showed that aboveground biomass did not change with any inoculum compared to the control. The P concentration in maize was higher for D. cerradensis TK-1 and C. pellucida SZ-3 inoculation than for the control. However, inoculation with A. morrowiae AP-5 and A. longula F-1 did not change P concentrations from the control. This indicates that D. cerradensis TK-1 and C. pellucida SZ-3 are more effective in promoting P uptake in maize than in A morrowiae AP-5 and A. longula F-1. Based on field and pot experiments, our findings suggest that tillage practices lead to alterations in the AMF communities that colonize the roots, and this shift may also contribute to changes in P uptake and crop growth. Full article
(This article belongs to the Special Issue Microbiome in Ecosystem 2.0)
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19 pages, 965 KiB  
Article
Optimization of Probiotic Lactobacilli Production for In-Feed Supplementation to Feedlot Cattle
by Cecilia Aristimuño Ficoseco, Flavia I. Mansilla, Graciela M. Vignolo and María E. Fátima Nader-Macías
Appl. Microbiol. 2023, 3(2), 339-357; https://doi.org/10.3390/applmicrobiol3020024 - 30 Mar 2023
Cited by 2 | Viewed by 2806
Abstract
The selection of probiotic bacteria based on their beneficial characteristics does not necessarily mean they can be later scaled up and used for technological applications and formula design. Three probiotic strains—Lactobacillus acidophilus CRL2074, Limosilactobacillus fermentum CRL2085, and Limosolactobacillus mucosae CRL2069, originally isolated [...] Read more.
The selection of probiotic bacteria based on their beneficial characteristics does not necessarily mean they can be later scaled up and used for technological applications and formula design. Three probiotic strains—Lactobacillus acidophilus CRL2074, Limosilactobacillus fermentum CRL2085, and Limosolactobacillus mucosae CRL2069, originally isolated from feedlot cattle feces—have demonstrated beneficial characteristics when used as in-feed probiotics. Therefore, the current study was conducted to develop a low-cost culture medium to optimize growth conditions to enhance biomass production. The study also sought to identify appropriate cryoprotective agents to sustain high functional cell numbers after freeze drying. A central composite design was applied to determine the optimal medium composition. This yielded a simplified, low-cost effective medium containing 3% molasses and industrial yeast extracts (0.5 to 2.5%) as carbon and nitrogen sources, which were added to a basal medium for each strain. Established production conditions at 37 °C, without agitation, and pH-controlled for the CRL2085 and CRL2069 strains, and free pH for the CRL2074 strain, allowed us to obtain biomass yields of 12.95, 18.20, and 12.25 g, respectively, at 24-h incubation, compared with the MRS medium. In addition, the cryoprotective effect of the selected agents was demonstrated to be strain-dependent. Thus, the highest viability (109–1010 CFU/g), stability during 30-d storage, and survival rate (88–99%) were achieved when 10% MSG (monosodium glutamate), sucrose + fructose + trehalose + WPC (whey protein concentrate) + 10% MSG, and 1.2% WPC + 10% trehalose, were used for freeze drying CRL2074, CRL2085, and CRL2069, respectively. Moreover, the probiotic strains retained their probiotic functionality when hydrophobic characteristics were evaluated. These results highlight the need to perform strain-specific evaluation of the critical factors involved in the large-scale production of probiotic lactobacilli to sustain viability and stability after the freeze drying and storage processes. Full article
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17 pages, 369 KiB  
Review
Univariate and Multivariate Statistical Analysis of Microbiome Data: An Overview
by Hani Aldirawi and Franceskrista G. Morales
Appl. Microbiol. 2023, 3(2), 322-338; https://doi.org/10.3390/applmicrobiol3020023 - 27 Mar 2023
Cited by 2 | Viewed by 2737
Abstract
Microbiome data is high dimensional, sparse, compositional, and over-dispersed. Therefore, modeling microbiome data is very challenging and it is an active research area. Microbiome analysis has become a progressing area of research as microorganisms constitute a large part of life. Since many methods [...] Read more.
Microbiome data is high dimensional, sparse, compositional, and over-dispersed. Therefore, modeling microbiome data is very challenging and it is an active research area. Microbiome analysis has become a progressing area of research as microorganisms constitute a large part of life. Since many methods of microbiome data analysis have been presented, this review summarizes the challenges, methods used, and the advantages and disadvantages of those methods, to serve as an updated guide for those in the field. This review also compared different methods of analysis to progress the development of newer methods. Full article
(This article belongs to the Special Issue Microbiome in Ecosystem 2.0)
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10 pages, 272 KiB  
Review
An In-Depth Review of the Benefits of Antibiotic Use in the Treatment of Borreliosis in Pregnancy
by Michael J. Cook, David Moynan, Gordana Avramovic and John S. Lambert
Appl. Microbiol. 2023, 3(2), 312-321; https://doi.org/10.3390/applmicrobiol3020022 - 23 Mar 2023
Cited by 1 | Viewed by 2388
Abstract
Evidence of congenital transmission of Lyme disease from mother to fetus has been investigated since the 1980s. This study reports the results of a retrospective analysis of 31 studies described in 27 papers published in a 2018 review article. Analysis of these identified [...] Read more.
Evidence of congenital transmission of Lyme disease from mother to fetus has been investigated since the 1980s. This study reports the results of a retrospective analysis of 31 studies described in 27 papers published in a 2018 review article. Analysis of these identified statistically probable transmission in 13 (42%) of the 31 studies and possible transmission in 2 (6%). Most studies included mothers who had been treated with antimicrobials. When no antimicrobials were used, 74% of the pregnancies had adverse outcomes. When oral antimicrobials were used, 29% of pregnancies had adverse outcomes. When intravenous (IV) antimicrobials were used, adverse outcomes dropped to 12% of the pregnancies. This is a six-fold reduction in risk compared with no antimicrobial treatment. Some studies did not define whether oral or IV antimicrobials were used. When these results were included, adverse outcomes were 30 times higher for untreated mothers. Adverse outcomes included deaths, heart anomalies, and preterm births. Full article
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