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Microorganisms, Volume 7, Issue 5 (May 2019) – 40 articles

Cover Story (view full-size image): Clostridium estertheticum is a psychrotolerant spore-forming anaerobe, and the main cause of blown pack spoilage (BPS). BPS occurs in vacuum-packed meat without temperature abuse. BPS occurs worldwide, accounting for significant losses in the meat industry. Several factors, including animal physiology, determine the ultimate pH and glucose levels in meat, and post-slaughter exposure of meat to environmental microbial contaminants may promote BPS. The early detection and prevention of BPS has been hampered by a lack of studies, due to the poor growth of Cl. estertheticum under normal laboratory conditions. However, the few strains of Cl. estertheticum that are available have been characterized phenotypically and provided vital data that can be used to control BPS. These include growth conditions in meat juice, inactivation by peroxyacetic acid, and inhibition by lactic acid bacteria. View this paper.
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13 pages, 3226 KiB  
Article
Engineered Lactococcus lactis Secreting IL-23 Receptor-Targeted REX Protein Blockers for Modulation of IL-23/Th17-Mediated Inflammation
by Tina Vida Plavec, Milan Kuchař, Anja Benko, Veronika Lišková, Jiří Černý, Aleš Berlec and Petr Malý
Microorganisms 2019, 7(5), 152; https://doi.org/10.3390/microorganisms7050152 - 27 May 2019
Cited by 23 | Viewed by 5040
Abstract
Lactococcus lactis, a probiotic bacterium of food origin, has recently been demonstrated as a suitable strain for the production and in vivo delivery of therapeutically important proteins into the gut. We aimed to engineer recombinant L. lactis cells producing/secreting REX binding proteins [...] Read more.
Lactococcus lactis, a probiotic bacterium of food origin, has recently been demonstrated as a suitable strain for the production and in vivo delivery of therapeutically important proteins into the gut. We aimed to engineer recombinant L. lactis cells producing/secreting REX binding proteins that have been described as IL-23 receptor (IL-23R) blockers and IL-23R antagonists suppressing the secretion of cytokine IL-17A, a pivotal step in the T-helper Th17-mediated pro-inflammatory cascade, as well as in the development of autoimmune diseases, including inflammatory bowel disease (IBD). To reach this goal, we introduced cDNA sequences coding for REX009, REX115, and REX125 proteins into plasmid vectors carrying a Usp45 secretion signal, a FLAG tag sequence consensus, and a LysM-containing cA surface anchor (AcmA), thus allowing cell–surface peptidoglycan anchoring. These plasmids, or their non-FLAG/non-AcmA versions, were introduced into L. lactis host cells, thus generating unique recombinant L. lactis–REX strains. We demonstrate that all three REX proteins are expressed in L. lactis cells and are efficiently displayed on the bacterial surface, as tested by flow cytometry using an anti-FLAG antibody conjugate. Upon 10-fold concentration of the conditioned media, a REX125 secretory variant can be detected by Western blotting. To confirm that the FLAG/non-FLAG REX proteins displayed by L. lactis retain their binding specificity, cell-surface interactions of REX proteins with an IL-23R-IgG chimera were demonstrated by flow cytometry. In addition, statistically significant binding of secreted REX009 and REX115 proteins to bacterially produced, soluble human IL-23R was confirmed by ELISA. We conclude that REX-secreting L. lactis strains were engineered that might serve as IL-23/IL-23R blockers in an experimentally induced mouse model of colitis. Full article
(This article belongs to the Special Issue Gastrointestinal Microbiota Impacts Human Health and Disease)
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8 pages, 764 KiB  
Technical Note
Improved Positive Predictive Performance of Listeria Indicator Broth: A Sensitive Environmental Screening Test to Identify Presumptively Positive Swab Samples
by Alan D. Olstein and Joellen M. Feirtag
Microorganisms 2019, 7(5), 151; https://doi.org/10.3390/microorganisms7050151 - 27 May 2019
Cited by 2 | Viewed by 2483
Abstract
PDX-LIB, Listeria Indicator Broth, was developed as a proprietary sensitive screening test to identify presumptively positive environmental swab samples for Listeria sp. The original formulation, while sensitive, initially proved to exhibit acceptable levels of false positive test results. Paradigm Diagnostics has been undertaken [...] Read more.
PDX-LIB, Listeria Indicator Broth, was developed as a proprietary sensitive screening test to identify presumptively positive environmental swab samples for Listeria sp. The original formulation, while sensitive, initially proved to exhibit acceptable levels of false positive test results. Paradigm Diagnostics has been undertaken to modify the medium formulation to render it more selective while not sacrificing its sensitivity. After identification of a candidate formulation through laboratory studies, a field trial was conducted to validate the test performance parameters, including the true positive frequency and false positive frequency in several different food-processing facilities. Identical swab samples were enriched in both the original medium formulation and the new formulation. Presumptive positive samples were confirmed by plating on selective differential agar and qPCR analysis. The field trial data demonstrate that the new formulation significantly reduces the frequency of false positive samples compared to the original Listeria Indicator Broth formulation, without compromising the sensitivity of the original formulation. The new medium formulation resulted in no false positive samples compared to the 54% increased presumptive positive samples obtained with the original medium formulation. Full article
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21 pages, 4541 KiB  
Article
Oral Beta-Lactamase Protects the Canine Gut Microbiome from Oral Amoxicillin-Mediated Damage
by Sheila Connelly, Brian Fanelli, Nur A. Hasan, Rita R. Colwell and Michael Kaleko
Microorganisms 2019, 7(5), 150; https://doi.org/10.3390/microorganisms7050150 - 27 May 2019
Cited by 10 | Viewed by 4593
Abstract
Antibiotics damage the gut microbiome, which can result in overgrowth of pathogenic microorganisms and emergence of antibiotic resistance. Inactivation of antibiotics in the small intestine represents a novel strategy to protect the colonic microbiota. SYN-004 (ribaxamase) is a beta-lactamase formulated for oral delivery [...] Read more.
Antibiotics damage the gut microbiome, which can result in overgrowth of pathogenic microorganisms and emergence of antibiotic resistance. Inactivation of antibiotics in the small intestine represents a novel strategy to protect the colonic microbiota. SYN-004 (ribaxamase) is a beta-lactamase formulated for oral delivery intended to degrade intravenously administered beta-lactam antibiotics in the gastrointestinal (GI) tract. The enteric coating of ribaxamase protects the enzyme from stomach acid and mediates pH-dependent release in the upper small intestine, the site of antibiotic biliary excretion. Clinical benefit was established in animal and human studies in which ribaxamase was shown to degrade ceftriaxone in the GI tract, thereby preserving the gut microbiome, significantly reducing Clostridioides difficile disease, and attenuating antibiotic resistance. To expand ribaxamase utility to oral beta-lactams, delayed release formulations of ribaxamase, SYN-007, were engineered to allow enzyme release in the lower small intestine, distal to the site of oral antibiotic absorption. Based on in vitro dissolution profiles, three SYN-007 formulations were selected for evaluation in a canine model of antibiotic-mediated gut dysbiosis. Dogs received amoxicillin (40 mg/kg, PO, TID) +/- SYN-007 (10 mg, PO, TID) for five days. Serum amoxicillin levels were measured after the first and last antibiotic doses and gut microbiomes were evaluated using whole genome shotgun sequence metagenomics analyses of fecal DNA prior to and after antibiotic treatment. Serum amoxicillin levels did not significantly differ +/- SYN-007 after the first dose for all SYN-007 formulations, while only one SYN-007 formulation did not significantly reduce systemic antibiotic concentrations after the last dose. Gut microbiomes of animals receiving amoxicillin alone displayed significant loss of diversity and emergence of antibiotic resistance genes. In contrast, for animals receiving amoxicillin + SYN-007, microbiome diversities were not altered significantly and the presence of antibiotic resistance genes was reduced. These data demonstrate that SYN-007 diminishes amoxicillin-mediated microbiome disruption and mitigates emergence and propagation of antibiotic resistance genes without interfering with antibiotic systemic absorption. Thus, SYN-007 has the potential to protect the gut microbiome by inactivation of beta-lactam antibiotics when administered by both oral and parenteral routes and to reduce emergence of antibiotic-resistant pathogens. Full article
(This article belongs to the Special Issue Gastrointestinal Microbiota Impacts Human Health and Disease)
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13 pages, 2871 KiB  
Article
The Chlamydia trachomatis Extrusion Exit Mechanism Is Regulated by Host Abscission Proteins
by Meghan Zuck and Kevin Hybiske
Microorganisms 2019, 7(5), 149; https://doi.org/10.3390/microorganisms7050149 - 25 May 2019
Cited by 6 | Viewed by 4133
Abstract
The cellular exit strategies of intracellular pathogens have a direct impact on microbial dissemination, transmission, and engagement of immune responses of the host. Chlamydia exit their host via a budding mechanism called extrusion, which offers protective benefits to Chlamydia as they navigate their [...] Read more.
The cellular exit strategies of intracellular pathogens have a direct impact on microbial dissemination, transmission, and engagement of immune responses of the host. Chlamydia exit their host via a budding mechanism called extrusion, which offers protective benefits to Chlamydia as they navigate their extracellular environment. Many intracellular pathogens co-opt cellular abscission machinery to facilitate cell exit, which is utilized to perform scission of two newly formed daughter cells following mitosis. Similar to viral budding exit strategies, we hypothesize that an abscission-like mechanism is required to physically sever the chlamydial extrusion from the host cell, co-opting the membrane fission activities of the endosomal sorting complex required for transport (ESCRT) family of proteins that are necessary for cellular scission events, including abscission. To test this, C. trachomatis L2-infected HeLa cells were depleted of key abscission machinery proteins charged multivesicle body protein 4b (CHMP4B), ALIX, centrosome protein 55 (CEP55), or vacuolar protein sorting-associated protein 4A (VPS4A), using RNA interference (RNAi). Over 50% reduction in extrusion formation was achieved by depletion of CHMP4B, VPS4A, and ALIX, but no effect on extrusion was observed with CEP55 depletion. These results demonstrate a role for abscission machinery in C. trachomatis extrusion from the host cell, with ALIX, VPS4A and CHMP4B playing key functional roles in optimal extrusion release. Full article
(This article belongs to the Special Issue Chlamydiae and Chlamydia like Bacteria)
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10 pages, 2102 KiB  
Review
Metabolite Profiling: A Tool for the Biochemical Characterisation of Mycobacterium sp.
by Margit Drapal and Paul D. Fraser
Microorganisms 2019, 7(5), 148; https://doi.org/10.3390/microorganisms7050148 - 25 May 2019
Cited by 5 | Viewed by 3482
Abstract
Over the last decades, the prevalence of drug-resistance in Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, has increased. These findings have rekindled interest in elucidating the unique adaptive molecular and biochemistry physiology of Mycobacterium. The use of metabolite profiling [...] Read more.
Over the last decades, the prevalence of drug-resistance in Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, has increased. These findings have rekindled interest in elucidating the unique adaptive molecular and biochemistry physiology of Mycobacterium. The use of metabolite profiling independently or in combination with other levels of “-omic” analyses has proven an effective approach to elucidate key physiological/biochemical mechanisms associated with Mtb throughout infection. The following review discusses the use of metabolite profiling in the study of tuberculosis, future approaches, and the technical and logistical limitations of the methodology. Full article
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15 pages, 982 KiB  
Article
Polyphasic Characterization of Yeasts and Lactic Acid Bacteria Metabolic Contribution in Semi-Solid Fermentation of Chinese Baijiu (Traditional Fermented Alcoholic Drink): Towards the Design of a Tailored Starter Culture
by Rufei Ma, Lu Sui, Jingsheng Zhang, Jinrong Hu and Ping Liu
Microorganisms 2019, 7(5), 147; https://doi.org/10.3390/microorganisms7050147 - 25 May 2019
Cited by 21 | Viewed by 4130
Abstract
Chinese Baijiu is principally produced through a spontaneous fermentation process, which involves complex microorganism communities. Among them, yeasts and lactic acid bacteria (LAB) are important communities. The study examined the isolated strains from fermented grains of Baijiu regarding their activity of α-amylase and [...] Read more.
Chinese Baijiu is principally produced through a spontaneous fermentation process, which involves complex microorganism communities. Among them, yeasts and lactic acid bacteria (LAB) are important communities. The study examined the isolated strains from fermented grains of Baijiu regarding their activity of α-amylase and glucoamylase, ethanol tolerance, glucose utilization, as well as metabolite production in the process of laboratory-scale sorghum-based fermentation. Selected strains (Saccharomycopsis fibuligera 12, Saccharomyces cerevisiae 3, and Pediococcus acidilactici 4) were blended in different combinations. The influence of selected strains on the metabolic variation in different semi-solid fermentations was investigated by gas chromatography–mass spectrometry (GC–MS) accompanied by multivariate statistical analysis. According to the principal component analysis (PCA), the metabolites produced varied in different mixtures of pure cultures. S. fibuligera produced various enzymes, particularly α-amylase and glucoamylase, and exhibited a better performance compared with other species regarding the ability to convert starch to soluble sugars and positively affect the production process of volatile compounds. S. cerevisiae had a high fermentation capacity, thereby contributing to substrates utilization. Lactic acid bacteria had a good ability to produce lactic acid. This study attaches importance to the special functions of S. fibuligera, S. cerevisiae, and P. acidilactici in Chinese Baijiu making, and investigates their metabolic characteristics in the process of lab-scale semi-solid fermentation. Full article
(This article belongs to the Section Food Microbiology)
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17 pages, 287 KiB  
Review
Chlamydiaceae: Diseases in Primary Hosts and Zoonosis
by Heng Choon Cheong, Chalystha Yie Qin Lee, Yi Ying Cheok, Grace Min Yi Tan, Chung Yeng Looi and Won Fen Wong
Microorganisms 2019, 7(5), 146; https://doi.org/10.3390/microorganisms7050146 - 24 May 2019
Cited by 68 | Viewed by 6416
Abstract
Bacteria of the Chlamydiaceae family are a type of Gram-negative microorganism typified by their obligate intracellular lifestyle. The majority of the members in the Chlamydiaceae family are known pathogenic organisms that primarily infect the host mucosal surfaces in both humans and animals. For [...] Read more.
Bacteria of the Chlamydiaceae family are a type of Gram-negative microorganism typified by their obligate intracellular lifestyle. The majority of the members in the Chlamydiaceae family are known pathogenic organisms that primarily infect the host mucosal surfaces in both humans and animals. For instance, Chlamydia trachomatis is a well-known etiological agent for ocular and genital sexually transmitted diseases, while C. pneumoniae has been implicated in community-acquired pneumonia in humans. Other chlamydial species such as C. abortus, C. caviae, C. felis, C. muridarum, C. pecorum, and C. psittaci are important pathogens that are associated with high morbidities in animals. Importantly, some of these animal pathogens have been recognized as zoonotic agents that pose a significant infectious threat to human health through cross-over transmission. The current review provides a succinct recapitulation of the characteristics as well as transmission for the previously established members of the Chlamydiaceae family and a number of other recently described chlamydial organisms. Full article
(This article belongs to the Special Issue Chlamydiae and Chlamydia like Bacteria)
15 pages, 3718 KiB  
Article
Interactions of Carvacrol, Caprylic Acid, Habituation, and Mild Heat for Pressure-Based Inactivation of O157 and Non-O157 Serogroups of Shiga Toxin-Producing Escherichia coli in Acidic Environment
by Md Niamul Kabir, Sadiye Aras, Abimbola Allison, Jayashan Adhikari, Shahid Chowdhury and Aliyar Fouladkhah
Microorganisms 2019, 7(5), 145; https://doi.org/10.3390/microorganisms7050145 - 23 May 2019
Cited by 14 | Viewed by 3094
Abstract
The current study investigated synergism of elevated hydrostatic pressure, habituation, mild heat, and antimicrobials for inactivation of O157 and non-O157 serogroups of Shiga toxin-producing Escherichia coli. Various times at a pressure intensity level of 450 MPa were investigated at 4 and 45 °C [...] Read more.
The current study investigated synergism of elevated hydrostatic pressure, habituation, mild heat, and antimicrobials for inactivation of O157 and non-O157 serogroups of Shiga toxin-producing Escherichia coli. Various times at a pressure intensity level of 450 MPa were investigated at 4 and 45 °C with and without carvacrol, and caprylic acid before and after three-day aerobic habituation in blueberry juice. Experiments were conducted in three biologically independent repetitions each consist of two replications and were statistically analyzed as a randomized complete block design study using ANOVA followed by Tukey- and Dunnett’s-adjusted mean separations. Under the condition of this experiment, habituation of the microbial pathogen played an influential (p < 0.05) role on inactivation rate of the pathogen. As an example, O157 and non-O157 serogroups were reduced (p < 0.05) by 1.4 and 1.6 Log CFU/mL after a 450 MPa treatment at 4 °C for seven min, respectively, before habituation. The corresponding log reductions (p < 0.05) after three-day aerobic habituation were: 2.6, and 3.3, respectively at 4 °C. Carvacrol and caprylic acid addition both augmented the pressure-based decontamination efficacy. As an example, Escherichia coli O157 were reduced (p < 0.05) by 2.6 and 4.2 log CFU/mL after a seven-min treatment at 450 MPa without, and with presence of 0.5% carvacrol, respectively, at 4 °C. Full article
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19 pages, 3487 KiB  
Article
MAV_4644 Interaction with the Host Cathepsin Z Protects Mycobacterium avium subsp. hominissuis from Rapid Macrophage Killing
by Matthew S. Lewis, Lia Danelishvili, Sasha J. Rose and Luiz E. Bermudez
Microorganisms 2019, 7(5), 144; https://doi.org/10.3390/microorganisms7050144 - 21 May 2019
Cited by 5 | Viewed by 4026
Abstract
Mycobacterium avium subspecies hominissuis (MAH) is an opportunistic pathogen that is ubiquitous in the environment and often isolated from faucets and showerheads. MAH mostly infects humans with an underlying disease, such as chronic pulmonary disorder, cystic fibrosis, or individuals that are immunocompromised. In [...] Read more.
Mycobacterium avium subspecies hominissuis (MAH) is an opportunistic pathogen that is ubiquitous in the environment and often isolated from faucets and showerheads. MAH mostly infects humans with an underlying disease, such as chronic pulmonary disorder, cystic fibrosis, or individuals that are immunocompromised. In recent years, MAH infections in patients without concurrent disease are increasing in prevalence as well. This pathogen is resistant to many antibiotics due to the impermeability of its envelope and due to the phenotypic resistance established within the host macrophages, making difficult to treat MAH infections. By screening a MAH transposon library for mutants that are susceptible to killing by reactive nitrogen intermediaries, we identified the MAV_4644 (MAV_4644:Tn) gene knockout clone that was also significantly attenuated in growth within the host macrophages. Complementation of the mutant restored the wild-type phenotype. The MAV_4644 gene encodes a dual-function protein with a putative pore-forming function and ADP-ribosyltransferase activity. Protein binding assay suggests that MAV_4644 interacts with the host lysosomal peptidase cathepsin Z (CTSZ), a key regulator of the cell signaling and inflammation. Pathogenic mycobacteria have been shown to suppress the action of many cathepsins to establish their intracellular niche. Our results demonstrate that knocking-down the cathepsin Z in human macrophages rescues the attenuated phenotype of MAV_4644:Tn clone. Although, the purified cathepsin Z by itself does not have any killing effect on MAH, it contributes to bacterial killing in the presence of the nitric oxide (NO). Our data suggest that the cathepsin Z is involved in early macrophage killing of MAH, and the virulence factor MAV_4644 protects the pathogen from this process. Full article
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14 pages, 1166 KiB  
Article
Pantoea spp. Associated with Smooth Crabgrass (Digitaria ischaemum) Seed Inhibit Competitor Plant Species
by Matthew T. Elmore, James F. White, Kathryn L. Kingsley, Katherine H. Diehl and Satish K. Verma
Microorganisms 2019, 7(5), 143; https://doi.org/10.3390/microorganisms7050143 - 21 May 2019
Cited by 8 | Viewed by 4295
Abstract
Digitaria ischaemum (Schreb.) Schreb. ex Muhl. and Poa annua L. are competitive, early successional species which are usually considered weeds in agricultural and turfgrass systems. Bacteria and fungi associated with D. ischaemum and P. annua seed may contribute to their competitiveness by antagonizing [...] Read more.
Digitaria ischaemum (Schreb.) Schreb. ex Muhl. and Poa annua L. are competitive, early successional species which are usually considered weeds in agricultural and turfgrass systems. Bacteria and fungi associated with D. ischaemum and P. annua seed may contribute to their competitiveness by antagonizing competitor forbs, and were studied in axenic culture. Pantoea spp. were the most common bacterial isolate of D. ischaemum seed, while Epicoccum and Curvularia spp. were common fungal isolates. A variety of species were collected from non-surface sterilized P. annua. Certain Pantoea spp. isolates were antagonistic to competitor forbs Taraxacum officinale, Trifolium repens. All bacterial isolates that affected T. officinale mortality were isolated from D. ischaemum seed while none of the P. annua isolates affected mortality. Two selected bacterial isolates identified as Pantoea ananatis were evaluated further on D. ischaemum, T. repens (a competitor forb) and P. annua (a competitor grass) alone and in combination with a Curvularia sp. fungus. These bacteria alone caused >65% T. repens seedling mortality but did not affect P. annua seedling mortality. These experiments demonstrate that Pantoea ananatis associated with D. ischaemum seeds is antagonistic to competitor forbs in axenic culture. The weedy character of D. ischaemum could at least in part stem from the possession of bacteria that are antagonistic to competitor species. Full article
(This article belongs to the Special Issue Plant Control of Symbiotic Microbe Behavior and Reproduction)
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12 pages, 260 KiB  
Review
Relevant Aspects of Clostridium estertheticum as a Specific Spoilage Organism of Vacuum-Packed Meat
by Joseph Wambui and Roger Stephan
Microorganisms 2019, 7(5), 142; https://doi.org/10.3390/microorganisms7050142 - 20 May 2019
Cited by 21 | Viewed by 5377
Abstract
Clostridium estertheticum is a psychrotolerant, gram-positive, motile, anaerobic, spore-forming, rod-shaped bacteria that causes blown pack spoilage (BPS). Spoilage occurs in vacuum-packed meat without temperature abuse. Having been reported in the last 30 years in several countries, BPS by Cl. estertheticum is a major [...] Read more.
Clostridium estertheticum is a psychrotolerant, gram-positive, motile, anaerobic, spore-forming, rod-shaped bacteria that causes blown pack spoilage (BPS). Spoilage occurs in vacuum-packed meat without temperature abuse. Having been reported in the last 30 years in several countries, BPS by Cl. estertheticum is a major issue around the world and presents a huge economic impact on the meat industry. Despite being an important spoilage microorganism, studies on Cl. estertheticum are challenged by numerous aspects. These include, lack or poor growth in laboratory media, long culturing periods, and unpredictable isolation on the media. These factors hamper the detection of Cl. estertheticum before occurrence of BPS, which further undermines efforts to prevent the occurrence of BPS. Nevertheless, considerable developments have taken place with regard to culture-independent methods. Although information on Cl. estertheticum is available, it is limited and remains highly fragmented. Therefore, this review collates the available information and discusses relevant aspects of Cl. estertheticum as a specific spoilage organism of BPS in vacuum-packed meat. Full article
(This article belongs to the Special Issue Bioprotection in Meat and Meat Products)
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9 pages, 474 KiB  
Article
Parachlamydia acanthamoebae Detected during a Pneumonia Outbreak in Southeastern Finland, in 2017–2018
by Kati Hokynar, Satu Kurkela, Tea Nieminen, Harri Saxen, Eero J. Vesterinen, Laura Mannonen, Risto Pietikäinen and Mirja Puolakkainen
Microorganisms 2019, 7(5), 141; https://doi.org/10.3390/microorganisms7050141 - 17 May 2019
Cited by 7 | Viewed by 2985
Abstract
Community-acquired pneumonia (CAP) is a common disease responsible for significant morbidity and mortality. However, the definite etiology of CAP often remains unresolved, suggesting that unknown agents of pneumonia remain to be identified. The recently discovered members of the order Chlamydiales, Chlamydia-related bacteria (CRB), [...] Read more.
Community-acquired pneumonia (CAP) is a common disease responsible for significant morbidity and mortality. However, the definite etiology of CAP often remains unresolved, suggesting that unknown agents of pneumonia remain to be identified. The recently discovered members of the order Chlamydiales, Chlamydia-related bacteria (CRB), are considered as possible emerging agents of CAP. Parachlamydia acanthamoebae is the most studied candidate. It survives and replicates inside free-living amoeba, which it might potentially use as a vehicle to infect animals and humans. A Mycoplasma pneumoniae outbreak was observed in Kymenlaakso region in Southeastern Finland during August 2017–January 2018. We determined the occurrence of Chlamydiales bacteria and their natural host, free-living amoeba in respiratory specimens collected during this outbreak with molecular methods. Altogether, 22/278 (7.9%) of the samples contained Chlamydiales DNA. By sequence analysis, majority of the CRBs detected were members of the Parachlamydiaceae family. Amoebal DNA was not detected within the sample material. Our study further proposes that Parachlamydiaceae could be a potential agent causing atypical CAP in children and adolescents. Full article
(This article belongs to the Special Issue Chlamydiae and Chlamydia like Bacteria)
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16 pages, 535 KiB  
Review
Chlamydia trachomatis and Chlamydia pneumoniae Interaction with the Host: Latest Advances and Future Prospective
by Marisa Di Pietro, Simone Filardo, Silvio Romano and Rosa Sessa
Microorganisms 2019, 7(5), 140; https://doi.org/10.3390/microorganisms7050140 - 16 May 2019
Cited by 32 | Viewed by 7418
Abstract
Research in Chlamydia trachomatis and Chlamydia pneumoniae has gained new traction due to recent advances in molecular biology, namely the widespread use of the metagenomic analysis and the development of a stable genomic transformation system, resulting in a better understanding of Chlamydia pathogenesis. [...] Read more.
Research in Chlamydia trachomatis and Chlamydia pneumoniae has gained new traction due to recent advances in molecular biology, namely the widespread use of the metagenomic analysis and the development of a stable genomic transformation system, resulting in a better understanding of Chlamydia pathogenesis. C. trachomatis, the leading cause of bacterial sexually transmitted diseases, is responsible of cervicitis and urethritis, and C. pneumoniae, a widespread respiratory pathogen, has long been associated with several chronic inflammatory diseases with great impact on public health. The present review summarizes the current evidence regarding the complex interplay between C. trachomatis and host defense factors in the genital micro-environment as well as the key findings in chronic inflammatory diseases associated to C. pneumoniae. Full article
(This article belongs to the Special Issue Chlamydiae and Chlamydia like Bacteria)
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12 pages, 234 KiB  
Review
Host–Microbe Interactions and Gut Health in Poultry—Focus on Innate Responses
by Leon J. Broom
Microorganisms 2019, 7(5), 139; https://doi.org/10.3390/microorganisms7050139 - 16 May 2019
Cited by 17 | Viewed by 5320
Abstract
Commercial poultry are continually exposed to, frequently pathogenic, microorganisms, usually via mucosal surfaces such as the intestinal mucosa. Thus, understanding host–microbe interactions is vital. Many of these microorganisms may have no or limited contact with the host, while most of those interacting more [...] Read more.
Commercial poultry are continually exposed to, frequently pathogenic, microorganisms, usually via mucosal surfaces such as the intestinal mucosa. Thus, understanding host–microbe interactions is vital. Many of these microorganisms may have no or limited contact with the host, while most of those interacting more meaningfully with the host will be dealt with by the innate immune response. Fundamentally, poultry have evolved to have immune responses that are generally appropriate and adequate for their acquired microbiomes, although this is challenged by commercial production practices. Innate immune cells and their functions, encompassing inflammatory responses, create the context for neutralising the stimulus and initiating resolution. Dysregulated inflammatory responses can be detrimental but, being a highly conserved biological process, inflammation is critical for host defence. Heterogeneity and functional plasticity of innate immune cells is underappreciated and offers the potential for (gut) health interventions, perhaps including exogenous opportunities to influence immune cell metabolism and thus function. New approaches could focus on identifying and enhancing decisive but less harmful immune processes, improving the efficiency of innate immune cells (e.g., targeted, efficient microbial killing) and promoting phenotypes that drive resolution of inflammation. Breeding strategies and suitable exogenous interventions offer potential solutions to enhance poultry gut health, performance and welfare. Full article
(This article belongs to the Special Issue Gut Health in Poultry Production)
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14 pages, 648 KiB  
Article
Community- and Hospital-Acquired Klebsiella pneumoniae Urinary Tract Infections in Portugal: Virulence and Antibiotic Resistance
by Cátia Caneiras, Luis Lito, José Melo-Cristino and Aida Duarte
Microorganisms 2019, 7(5), 138; https://doi.org/10.3390/microorganisms7050138 - 16 May 2019
Cited by 78 | Viewed by 8497
Abstract
Klebsiella pneumoniae is a clinically relevant pathogen and a frequent cause of hospital-acquired (HA) and community-acquired (CA) urinary tract infections (UTI). The increased resistance of this pathogen is leading to limited therapeutic options. To investigate the epidemiology, virulence, and antibiotic resistance profile of [...] Read more.
Klebsiella pneumoniae is a clinically relevant pathogen and a frequent cause of hospital-acquired (HA) and community-acquired (CA) urinary tract infections (UTI). The increased resistance of this pathogen is leading to limited therapeutic options. To investigate the epidemiology, virulence, and antibiotic resistance profile of K. pneumoniae in urinary tract infections, we conducted a multicenter retrospective study for a total of 81 isolates (50 CA-UTI and 31 HA-UTI) in Portugal. The detection and characterization of resistance and virulence determinants were performed by molecular methods (PCR, PCR-based replicon typing, and multilocus sequence typing (MLST)). Out of 50 CA-UTI isolates, six (12.0%) carried β-lactamase enzymes, namely blaTEM-156 (n = 2), blaTEM-24 (n = 1), blaSHV-11 (n = 1), blaSHV-33 (n = 1), and blaCTX-M-15 (n = 1). All HA-UTI were extended-spectrum β-lactamase (ESBL) producers and had a multidrug resistant profile as compared to the CA-UTI isolates, which were mainly resistant to ciprofloxacin, levofloxacin, tigecycline, and fosfomycin. In conclusion, in contrast to community-acquired isolates, there is an overlap between virulence and multidrug resistance for hospital-acquired UTI K. pneumoniae pathogens. The study is the first to report different virulence characteristics for hospital and community K. pneumoniae pathogens, despite the production of β-lactamase and even with the presence of CTX-M-15 ESBL, a successful international ST15 clone, which were identified in both settings. This highlights that a focus on genomic surveillance should remain a priority in the hospital environment. Full article
(This article belongs to the Special Issue Multidrug-Resistant Pathogens)
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16 pages, 1228 KiB  
Review
Shiga-Toxin Producing Escherichia Coli in Brazil: A Systematic Review
by Vinicius Silva Castro, Eduardo Eustáquio de Souza Figueiredo, Kim Stanford, Tim McAllister and Carlos Adam Conte-Junior
Microorganisms 2019, 7(5), 137; https://doi.org/10.3390/microorganisms7050137 - 16 May 2019
Cited by 24 | Viewed by 4988
Abstract
Shiga-toxin producing E. coli (STEC) can cause serious illnesses, including hemorrhagic colitis and hemolytic uremic syndrome. This is the first systematic review of STEC in Brazil, and will report the main serogroups detected in animals, food products and foodborne diseases. Data were obtained [...] Read more.
Shiga-toxin producing E. coli (STEC) can cause serious illnesses, including hemorrhagic colitis and hemolytic uremic syndrome. This is the first systematic review of STEC in Brazil, and will report the main serogroups detected in animals, food products and foodborne diseases. Data were obtained from online databases accessed in January 2019. Papers were selected from each database using the Mesh term entries. Although no human disease outbreaks in Brazil related to STEC has been reported, the presence of several serogroups such as O157 and O111 has been verified in animals, food, and humans. Moreover, other serogroups monitored by international federal agencies and involved in outbreak cases worldwide were detected, and other unusual strains were involved in some isolated individual cases of foodborne disease, such as serotype O118:H16 and serogroup O165. The epidemiological data presented herein indicates the presence of several pathogenic serogroups, including O157:H7, O26, O103, and O111, which have been linked to disease outbreaks worldwide. As available data are concentrated in the Sao Paulo state and almost completely lacking in outlying regions, epidemiological monitoring in Brazil for STEC needs to be expanded and food safety standards for this pathogen should be aligned to that of the food safety standards of international bodies. Full article
(This article belongs to the Special Issue Shiga Toxin-Producing Escherichia coli)
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15 pages, 1441 KiB  
Article
Presence of Mycobacterium avium Subspecies paratuberculosis Monitored Over Varying Temporal and Spatial Scales in River Catchments: Persistent Routes for Human Exposure
by Hollian Richardson, Glenn Rhodes, Peter Henrys, Luigi Sedda, Andrew J. Weightman and Roger W. Pickup
Microorganisms 2019, 7(5), 136; https://doi.org/10.3390/microorganisms7050136 - 15 May 2019
Cited by 7 | Viewed by 4379
Abstract
Mycobacterium avium subspecies paratuberculosis (Map) was monitored by quantitative PCR over a range of temporal and spatial scales in the River Tywi catchment. This study shows the persistence of Map over a 10-year period with little change, which correlates with the [...] Read more.
Mycobacterium avium subspecies paratuberculosis (Map) was monitored by quantitative PCR over a range of temporal and spatial scales in the River Tywi catchment. This study shows the persistence of Map over a 10-year period with little change, which correlates with the recognised levels of Johne’s disease in British herds over that period (aim 1). Map was quantified within the river at up to 108 cell equivalents L−1 and was shown to be consistently present when monitored over finer timescales (aim 4). Small wastewater treatment plants where the ingress of human-associated Map might be expected had no significant effect (aim 2). Map was found for the first time to be located in natural river foams providing another route for spread via aerosols (aim 5). This study provides evidence for the environmental continuum of Map from the grazing infected animal via rain driven runoff through field drains and streams into main rivers; with detection at a high frequency throughout the year. Should Map need to be monitored in the future, we recommend that weekly or monthly sampling from a fixed location on a river will capture an adequate representation of the flow dynamics of Map in a catchment (aim 3). The human exposure to Map during this process and its impact on human health remains unquantified. Full article
(This article belongs to the Special Issue Non-Tuberculous Mycobacteria: Emerging Diseases and Health Impacts)
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14 pages, 2466 KiB  
Article
Oral Administration of a Select Mixture of Lactobacillus and Bacillus Alleviates Inflammation and Maintains Mucosal Barrier Integrity in the Ileum of Pigs Challenged with Salmonella Infantis
by Xiao Liu, Bing Xia, Ting He, Dan Li, Jin-Hui Su, Liang Guo, Jiu-feng Wang and Yao-Hong Zhu
Microorganisms 2019, 7(5), 135; https://doi.org/10.3390/microorganisms7050135 - 15 May 2019
Cited by 24 | Viewed by 3386
Abstract
Salmonella is important as both a cause of clinical disease in swine and as a source of food-borne transmission of disease to humans. Lactobacillus and Bacillus are often used as antibiotic substitutes to prevent Salmonella infection. In this study, we evaluated the effects [...] Read more.
Salmonella is important as both a cause of clinical disease in swine and as a source of food-borne transmission of disease to humans. Lactobacillus and Bacillus are often used as antibiotic substitutes to prevent Salmonella infection. In this study, we evaluated the effects of a select mixture of Lactobacillus johnsonii L531, Bacillus licheniformis BL1721 and Bacillus subtilis BS1715 (LBB-mix) in prevention of Salmonella enterica serovar Infantis infection in a pig model. LBB-mix was orally administered to newly weaned piglets for seven days before S. Infantis challenge. LBB-mix pretreatment ameliorated S. Infantis-induced fever, leukocytosis, growth performance loss, and ileal inflammation. Pre-administration of LBB-mix reduced the number of Salmonella in the feces but increased the number of goblet cells in the ileum. S. Infantis infection resulted in an increase in cell death in the ileum, this increase was attenuated by LBB-mix consumption. Claudin 1 and cleaved caspase-1 expression was decreased in the ileum of pigs challenged with S. Infantis, but not in pigs pretreated with LBB-mix. In conclusion, our data indicate that a select LBB-mix has positive effects on controlling S. Infantis infection via alleviating inflammation and maintaining the intestinal mucosal barrier integrity in pigs. Full article
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10 pages, 783 KiB  
Article
Combined Effect of Vacuum Packaging, Fennel and Savory Essential Oil Treatment on the Quality of Chicken Thighs
by Miroslava Kačániová, Martin Mellen, Nenad L. Vukovic, Maciej Kluz, Czeslaw Puchalski, Peter Haščík and Simona Kunová
Microorganisms 2019, 7(5), 134; https://doi.org/10.3390/microorganisms7050134 - 15 May 2019
Cited by 25 | Viewed by 3477
Abstract
The aim of the present work was to evaluate the microbiological quality of chicken thighs after treatment by fennel (Foeniculum vulgare) and savory (Satureja hortensis) essential oil, stored under vacuum packaging (VP) at 4 ± 0.5 °C for a [...] Read more.
The aim of the present work was to evaluate the microbiological quality of chicken thighs after treatment by fennel (Foeniculum vulgare) and savory (Satureja hortensis) essential oil, stored under vacuum packaging (VP) at 4 ± 0.5 °C for a period of 16 days. The following treatments of chicken thighs were used: Air-packaging control samples (APCS), vacuum-packaging control samples (VPC), vacuum-packaging (VP) control samples with rapeseed oil (VPRO), VP (vacuum-packaging) with fennel essential oil at concentrations 0.2% v/w (VP + F), and VP with savory essential oil at concentration 0.2% v/w (VP + S). The quality assessment of APCS, VPC, VPRO, VP + F and VP + S products was established by microbiological analysis. The microbiological parameters as the total viable counts of bacteria of the Enterobacteriaceae family, lactic acid bacteria (LAB), and Pseudomonas spp. were detected. Bacterial species were identified with the MALDI-TOF MS Biotyper. The combination of essential oils and vacuum packaging had a significant effect (p < 0.05) on the reduction of total viable counts (TVC) compared with control group without vacuum packaging and the untreated control group. Though 15 genera and 46 species were isolated with scores higher than 2.3 from the chicken samples. Full article
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26 pages, 862 KiB  
Review
Arthritogenic Alphaviruses: A Worldwide Emerging Threat?
by Laura I. Levi and Marco Vignuzzi
Microorganisms 2019, 7(5), 133; https://doi.org/10.3390/microorganisms7050133 - 14 May 2019
Cited by 47 | Viewed by 6644
Abstract
Arthritogenic alphaviruses are responsible for a dengue-like syndrome associated with severe debilitating polyarthralgia that can persist for months or years and impact life quality. Chikungunya virus is the most well-known member of this family since it was responsible for two worldwide epidemics with [...] Read more.
Arthritogenic alphaviruses are responsible for a dengue-like syndrome associated with severe debilitating polyarthralgia that can persist for months or years and impact life quality. Chikungunya virus is the most well-known member of this family since it was responsible for two worldwide epidemics with millions of cases in the last 15 years. However, other arthritogenic alphaviruses that are as of yet restrained to specific territories are the cause of neglected tropical diseases: O’nyong’nyong virus in Sub-Saharan Africa, Mayaro virus in Latin America, and Ross River virus in Australia and the Pacific island countries and territories. This review evaluates their emerging potential in light of the current knowledge for each of them and in comparison to chikungunya virus. Full article
(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)
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23 pages, 3773 KiB  
Article
In Vitro Activation of Seed-Transmitted Cultivation-Recalcitrant Endophytic Bacteria in Tomato and Host–Endophyte Mutualism
by Sadiq Pasha Shaik and Pious Thomas
Microorganisms 2019, 7(5), 132; https://doi.org/10.3390/microorganisms7050132 - 14 May 2019
Cited by 16 | Viewed by 6993
Abstract
This study was aimed at exploring seed transmission of endophytic bacteria in tomato utilizing aseptic in vitro conditions. Cultivation-based studies were undertaken on two tomato cultivars “Arka Vikas” and “Arka Abha” employing surface sterilized seeds, aseptically germinated seeds and in vitro grown seedlings [...] Read more.
This study was aimed at exploring seed transmission of endophytic bacteria in tomato utilizing aseptic in vitro conditions. Cultivation-based studies were undertaken on two tomato cultivars “Arka Vikas” and “Arka Abha” employing surface sterilized seeds, aseptically germinated seeds and in vitro grown seedlings at different stages. Bacillus sp. appeared primarily as seed externally-associated bacteria. Tissue homogenate from extensively surface-sterilized seeds, day-3 germinating seeds, or 10-day in vitro seedlings did not show any cultivable bacteria on two bacteriological media. Indexing of 4-week old healthy seedlings with seed-coat removal following seed germination showed bacterial association in 50–75% seedlings yielding 106–107 cfu g−1 tissues. Four endophytic bacteria appeared common to both cultivars (Kosakonia, Ralstonia, Sphingomonas, Sphingobium spp.) with three additional species in “Arka Abha”. The bacterial strains showed a manifold increase in growth with host-tissue-extract supplementation. Seed inoculations with single-isolates stimulated germination or enhanced the seedling growth coupled with the activation of additional endophytic bacteria. In vitro seedlings upon recurrent medium-indexing over eight weeks showed gradual emergence of endophytic bacteria. The study reveals the seed internal colonization by different bacterial endophytes in a cultivation-recalcitrant form, their activation to cultivable state during seedling growth and transmission to seedlings with mutualistic effects. Full article
(This article belongs to the Special Issue Plant Control of Symbiotic Microbe Behavior and Reproduction)
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19 pages, 2682 KiB  
Article
The Transcription Factor Sfp1 Regulates the Oxidative Stress Response in Candida albicans
by Shao-Yu Lee, Hsueh-Fen Chen, Ying-Chieh Yeh, Yao-Peng Xue and Chung-Yu Lan
Microorganisms 2019, 7(5), 131; https://doi.org/10.3390/microorganisms7050131 - 14 May 2019
Cited by 13 | Viewed by 3827
Abstract
Candida albicans is a commensal that inhabits the skin and mucous membranes of humans. Because of the increasing immunocompromised population and the limited classes of antifungal drugs available, C. albicans has emerged as an important opportunistic pathogen with high mortality rates. During infection [...] Read more.
Candida albicans is a commensal that inhabits the skin and mucous membranes of humans. Because of the increasing immunocompromised population and the limited classes of antifungal drugs available, C. albicans has emerged as an important opportunistic pathogen with high mortality rates. During infection and therapy, C. albicans frequently encounters immune cells and antifungal drugs, many of which exert their antimicrobial activity by inducing the production of reactive oxygen species (ROS). Therefore, antioxidative capacity is important for the survival and pathogenesis of C. albicans. In this study, we characterized the roles of the zinc finger transcription factor Sfp1 in the oxidative stress response against C. albicans. A sfp1-deleted mutant was more resistant to oxidants and macrophage killing than wild-type C. albicans and processed an active oxidative stress response with the phosphorylation of the mitogen-activated protein kinase (MAPK) Hog1 and high CAP1 expression. Moreover, the sfp1-deleted mutant exhibited high expression levels of antioxidant genes in response to oxidative stress, resulting in a higher total antioxidant capacity, glutathione content, and glutathione peroxidase and superoxide dismutase enzyme activity than the wild-type C. albicans. Finally, the sfp1-deleted mutant was resistant to macrophage killing and ROS-generating antifungal drugs. Together, our findings provide a new understanding of the complex regulatory machinery in the C. albicans oxidative stress response. Full article
(This article belongs to the Special Issue Molecular Mechanisms of Fungal Virulence and Commensalism)
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32 pages, 659 KiB  
Review
Advances in Chemical and Biological Methods to Identify Microorganisms—From Past to Present
by Ricardo Franco-Duarte, Lucia Černáková, Snehal Kadam, Karishma S. Kaushik, Bahare Salehi, Antonio Bevilacqua, Maria Rosaria Corbo, Hubert Antolak, Katarzyna Dybka-Stępień, Martyna Leszczewicz, Saulo Relison Tintino, Veruska Cintia Alexandrino de Souza, Javad Sharifi-Rad, Henrique Douglas Melo Coutinho, Natália Martins and Célia F. Rodrigues
Microorganisms 2019, 7(5), 130; https://doi.org/10.3390/microorganisms7050130 - 13 May 2019
Cited by 227 | Viewed by 38556
Abstract
Fast detection and identification of microorganisms is a challenging and significant feature from industry to medicine. Standard approaches are known to be very time-consuming and labor-intensive (e.g., culture media and biochemical tests). Conversely, screening techniques demand a quick and low-cost grouping of bacterial/fungal [...] Read more.
Fast detection and identification of microorganisms is a challenging and significant feature from industry to medicine. Standard approaches are known to be very time-consuming and labor-intensive (e.g., culture media and biochemical tests). Conversely, screening techniques demand a quick and low-cost grouping of bacterial/fungal isolates and current analysis call for broad reports of microorganisms, involving the application of molecular techniques (e.g., 16S ribosomal RNA gene sequencing based on polymerase chain reaction). The goal of this review is to present the past and the present methods of detection and identification of microorganisms, and to discuss their advantages and their limitations. Full article
(This article belongs to the Special Issue Identification of Microorganisms: Old, New and Future Methods)
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13 pages, 4036 KiB  
Article
Response of Microbial Communities and Their Metabolic Functions to Drying–Rewetting Stress in a Temperate Forest Soil
by Dong Liu, Katharina M. Keiblinger, Sonja Leitner, Uwe Wegner, Michael Zimmermann, Stephan Fuchs, Christian Lassek, Katharina Riedel and Sophie Zechmeister-Boltenstern
Microorganisms 2019, 7(5), 129; https://doi.org/10.3390/microorganisms7050129 - 13 May 2019
Cited by 33 | Viewed by 5225
Abstract
Global climate change is predicted to alter drought–precipitation patterns, which will likely affect soil microbial communities and their functions, ultimately shifting microbially-mediated biogeochemical cycles. The present study aims to investigate the simultaneous variation of microbial community compositions and functions in response to drought [...] Read more.
Global climate change is predicted to alter drought–precipitation patterns, which will likely affect soil microbial communities and their functions, ultimately shifting microbially-mediated biogeochemical cycles. The present study aims to investigate the simultaneous variation of microbial community compositions and functions in response to drought and following rewetting events, using a soil metaproteomics approach. For this, an established field experiment located in an Austrian forest with two levels (moderate and severe stress) of precipitation manipulation was evaluated. The results showed that fungi were more strongly influenced by drying and rewetting (DRW) than bacteria, and that there was a drastic shift in the fungal community towards a more Ascomycota-dominated community. In terms of functional responses, a larger number of proteins and a higher functional diversity were observed in both moderate and severe DRW treatments compared to the control. Furthermore, in both DRW treatments a rise in proteins assigned to “translation, ribosomal structure, and biogenesis” and “protein synthesis” suggests a boost in microbial cell growth after rewetting. We also found that the changes within intracellular functions were associated to specific phyla, indicating that responses of microbial communities to DRW primarily shifted microbial functions. Microbial communities seem to respond to different levels of DRW stress by changing their functional potential, which may feed back to biogeochemical cycles. Full article
(This article belongs to the Special Issue Towards Integrated Multi-omics Analyses of Environmental Microbiota)
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29 pages, 3687 KiB  
Review
Propionibacterium acnes and Acne Vulgaris: New Insights from the Integration of Population Genetic, Multi-Omic, Biochemical and Host-Microbe Studies
by Joseph McLaughlin, Steven Watterson, Alison M. Layton, Anthony J. Bjourson, Emma Barnard and Andrew McDowell
Microorganisms 2019, 7(5), 128; https://doi.org/10.3390/microorganisms7050128 - 13 May 2019
Cited by 112 | Viewed by 17060
Abstract
The anaerobic bacterium Propionibacterium acnes is believed to play an important role in the pathophysiology of the common skin disease acne vulgaris. Over the last 10 years our understanding of the taxonomic and intraspecies diversity of this bacterium has increased tremendously, and with [...] Read more.
The anaerobic bacterium Propionibacterium acnes is believed to play an important role in the pathophysiology of the common skin disease acne vulgaris. Over the last 10 years our understanding of the taxonomic and intraspecies diversity of this bacterium has increased tremendously, and with it the realisation that particular strains are associated with skin health while others appear related to disease. This extensive review will cover our current knowledge regarding the association of P. acnes phylogroups, clonal complexes and sequence types with acne vulgaris based on multilocus sequence typing of isolates, and direct ribotyping of the P. acnes strain population in skin microbiome samples based on 16S rDNA metagenomic data. We will also consider how multi-omic and biochemical studies have facilitated our understanding of P. acnes pathogenicity and interactions with the host, thus providing insights into why certain lineages appear to have a heightened capacity to contribute to acne vulgaris development, while others are positively associated with skin health. We conclude with a discussion of new therapeutic strategies that are currently under investigation for acne vulgaris, including vaccination, and consider the potential of these treatments to also perturb beneficial lineages of P. acnes on the skin. Full article
(This article belongs to the Special Issue The Functions of the Microbiome in Skin Health and Disease)
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18 pages, 728 KiB  
Article
Biocidal Effectiveness of Selected Disinfectants Solutions Based on Water and Ozonated Water against Listeria monocytogenes Strains
by Krzysztof Skowron, Ewa Wałecka-Zacharska, Katarzyna Grudlewska, Agata Białucha, Natalia Wiktorczyk, Agata Bartkowska, Maria Kowalska, Stefan Kruszewski and Eugenia Gospodarek-Komkowska
Microorganisms 2019, 7(5), 127; https://doi.org/10.3390/microorganisms7050127 - 10 May 2019
Cited by 15 | Viewed by 3705
Abstract
The aim of this study was to compare the biocidal effectiveness of disinfectants solutions prepared with ozonated and non-ozonated water against Listeria monocytogenes. Six L. monocytogenes strains were the research material (four isolates from food: meat (LMO-M), dairy products (LMO-N), vegetables (LMO-W), [...] Read more.
The aim of this study was to compare the biocidal effectiveness of disinfectants solutions prepared with ozonated and non-ozonated water against Listeria monocytogenes. Six L. monocytogenes strains were the research material (four isolates from food: meat (LMO-M), dairy products (LMO-N), vegetables (LMO-W), and fish (LMO-R); one clinical strain (LMO-K) and reference strain ATCC 19111). The evaluation of the biocidal effectiveness of disinfectant solutions (QAC—quaternary ammonium compounds; OA—oxidizing agents; ChC—chlorine compounds; IC—iodine compounds; NANO—nanoparticles) was carried out, marking the MBC values. Based on the obtained results, the effectiveness coefficient (A) were calculated. The smaller the A value, the greater the efficiency of disinfection solutions prepared on the basis of ozonated versus non-ozonated water. Ozonated water showed biocidal efficacy against L. monocytogenes. Among tested disinfectentants, independent on type of water used for preparation, the most effective against L. monocytogenes were: QAC 1 (benzyl-C12-18-alkydimethyl ammonium chlorides) (1.00 × 10−5–1.00 × 10−4 g/mL) in quaternary ammonium compounds, OA 3 (peracetic acid, hydrogen peroxide, bis (sulphate) bis (peroxymonosulfate)) (3.08 × 10−4 –3.70 × 10−3 g/mL) in oxidizing agents, ChC 1 (chlorine dioxide) (5.00 × 10−8 –7.00 × 10−7 g/mL) in chlorine compounds, IC 1 (iodine) (1.05–2.15 g/mL) in iodine compounds, and NANO 1 (nanocopper) (1.08 × 10−4 – 1.47 × 10−4 g/mL) in nanoparticles. The values of the activity coefficient for QAC ranged from 0.10 to 0.40, for OA—0.15–0.84, for ChC—0.25–0.83, for IC—0.45–0.60, and for NANO—0.70–0.84. The preparation of disinfectants solution on the basis of ozonated water, improved the microbicidal efficiency of the tested disinfectant, especially the quaternary ammonium compounds. An innovative element of our work is the use of ozonated water for the preparation of working solutions of the disinfection agents. Use ozonated water can help to reduce the use of disinfectant concentrations and limit the increasing of microbial resistance to disinfectants. This paper provides many new information to optimize hygiene plans in food processing plants and limit the spread of microorganisms such as L. monocytogenes. Full article
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15 pages, 317 KiB  
Review
Members of the Lactobacillus Genus Complex (LGC) as Opportunistic Pathogens: A Review
by Franca Rossi, Carmela Amadoro and Giampaolo Colavita
Microorganisms 2019, 7(5), 126; https://doi.org/10.3390/microorganisms7050126 - 10 May 2019
Cited by 53 | Viewed by 7268
Abstract
Microorganisms belonging to the Lactobacillus genus complex (LGC) are naturally associated or deliberately added to fermented food products and are widely used as probiotic food supplements. Moreover, these bacteria normally colonize the mouth, gastrointestinal (GI) tract, and female genitourinary tract of humans. They [...] Read more.
Microorganisms belonging to the Lactobacillus genus complex (LGC) are naturally associated or deliberately added to fermented food products and are widely used as probiotic food supplements. Moreover, these bacteria normally colonize the mouth, gastrointestinal (GI) tract, and female genitourinary tract of humans. They exert multiple beneficial effects and are regarded as safe microorganisms. However, infections caused by lactobacilli, mainly endocarditis, bacteremia, and pleuropneumonia, occasionally occur. The relevance of Lactobacillus spp. and other members of the LGC as opportunistic pathogens in humans and related risk factors and predisposing conditions are illustrated in this review article with more emphasis on the species L. rhamnosus that has been more often involved in infection cases. The methods used to identify this species in clinical samples, to distinguish strains and to evaluate traits that can be associated to pathogenicity, as well as future perspectives for improving the identification of potentially pathogenic strains, are outlined. Full article
(This article belongs to the Special Issue Safety Aspects of Lactic Acid Bacteria)
15 pages, 1476 KiB  
Article
Impact of Binge Alcohol Intoxication on the Humoral Immune Response during Burkholderia spp. Infections
by Ryan M. Moreno, Victor Jimenez, Jr and Fernando P. Monroy
Microorganisms 2019, 7(5), 125; https://doi.org/10.3390/microorganisms7050125 - 9 May 2019
Cited by 1 | Viewed by 2895
Abstract
Burkholderia pseudomallei, the causative agent of melioidosis can occur in healthy humans, yet binge alcohol use is progressively being recognized as a major risk factor. Currently, no experimental studies have investigated the effects of binge alcohol on the adaptive immune system during [...] Read more.
Burkholderia pseudomallei, the causative agent of melioidosis can occur in healthy humans, yet binge alcohol use is progressively being recognized as a major risk factor. Currently, no experimental studies have investigated the effects of binge alcohol on the adaptive immune system during an active infection. In this study, we used B. thailandensis and B. vietnamiensis, to investigate the impact of a single binge alcohol episode on the humoral response during infection. Eight-week-old female C57BL/6 mice were administered alcohol comparable to human binge drinking (4.4 g/kg) or PBS intraperitoneally 30 min before intranasal infection. Mice infected with B. thailandensis had a 100% survival rate, while those infected with B. vietnamiensis had a 33% survivability rate when a binge alcohol dose was administered. B. thailandensis was detected in blood of mice administered alcohol at only 7 days post infection (PI), while those infected with B. vietnamiensis and receiving alcohol were found throughout the 28-day infection as well as in tissues at day 28 PI. Binge alcohol elevated IgM and delayed IgG specific to the whole cell lysate (WCL) of B. vietnamiensis but not B. thailandensis infections. Differences in immunogenicity of B. pseudomallei near-neighbors provide a framework for novel insights into the effects of binge alcohol’s suppression of the humoral immune response that can cause opportunistic infections in otherwise healthy hosts. Full article
(This article belongs to the Section Medical Microbiology)
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18 pages, 4877 KiB  
Review
Biosynthesis of Polyketides in Streptomyces
by Chandra Risdian, Tjandrawati Mozef and Joachim Wink
Microorganisms 2019, 7(5), 124; https://doi.org/10.3390/microorganisms7050124 - 6 May 2019
Cited by 72 | Viewed by 11811
Abstract
Polyketides are a large group of secondary metabolites that have notable variety in their structure and function. Polyketides exhibit a wide range of bioactivities such as antibacterial, antifungal, anticancer, antiviral, immune-suppressing, anti-cholesterol, and anti-inflammatory activity. Naturally, they are found in bacteria, fungi, plants, [...] Read more.
Polyketides are a large group of secondary metabolites that have notable variety in their structure and function. Polyketides exhibit a wide range of bioactivities such as antibacterial, antifungal, anticancer, antiviral, immune-suppressing, anti-cholesterol, and anti-inflammatory activity. Naturally, they are found in bacteria, fungi, plants, protists, insects, mollusks, and sponges. Streptomyces is a genus of Gram-positive bacteria that has a filamentous form like fungi. This genus is best known as one of the polyketides producers. Some examples of polyketides produced by Streptomyces are rapamycin, oleandomycin, actinorhodin, daunorubicin, and caprazamycin. Biosynthesis of polyketides involves a group of enzyme activities called polyketide synthases (PKSs). There are three types of PKSs (type I, type II, and type III) in Streptomyces responsible for producing polyketides. This paper focuses on the biosynthesis of polyketides in Streptomyces with three structurally-different types of PKSs. Full article
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14 pages, 1858 KiB  
Communication
Microbial and Functional Profile of the Ceca from Laying Hens Affected by Feeding Prebiotics, Probiotics, and Synbiotics
by Carolina Pineda-Quiroga, Daniel Borda-Molina, Diego Chaves-Moreno, Roberto Ruiz, Raquel Atxaerandio, Amélia Camarinha-Silva and Aser García-Rodríguez
Microorganisms 2019, 7(5), 123; https://doi.org/10.3390/microorganisms7050123 - 6 May 2019
Cited by 22 | Viewed by 4320
Abstract
Diet has an essential influence in the establishment of the cecum microbial communities in poultry, so its supplementation with safe additives, such as probiotics, prebiotics, and synbiotics might improve animal health and performance. This study showed the ceca microbiome modulations of laying hens, [...] Read more.
Diet has an essential influence in the establishment of the cecum microbial communities in poultry, so its supplementation with safe additives, such as probiotics, prebiotics, and synbiotics might improve animal health and performance. This study showed the ceca microbiome modulations of laying hens, after feeding with dry whey powder as prebiotics, Pediococcus acidilactici as probiotics, and the combination of both as synbiotics. A clear grouping of the samples induced per diet was observed (p < 0.05). Operational taxonomic units (OTUs) identified as Olsenella spp., and Lactobacillus crispatus increased their abundance in prebiotic and synbiotic treatments. A core of the main functions was shared between all metagenomes (45.5%), although the genes encoding for the metabolism of butanoate, propanoate, inositol phosphate, and galactose were more abundant in the prebiotic diet. The results indicated that dietary induced-changes in microbial composition did not imply a disturbance in the principal biological roles, while the specific functions were affected. Full article
(This article belongs to the Special Issue Gut Health in Poultry Production)
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