BMC Microbiology最新文献

{"title":"Guardians of resistance and virulence: detection of mec, femA, Van, pvl, hlg and spa genes in methicillin and vancomycin-resistant Staphylococcus aureus from clinical and food samples in Southwestern Nigeria.","authors":"Folasade Muibat Adeyemi, Omotayo Opemipo Oyedara, Nana Aishat Yusuf-Omoloye, Olaoniye Habeebat Ajigbewu, Onyinye Lynda Ndaji, Maryam Kikelomo Adegbite-Badmus, Taiwo Samson Olumakinde, Timilehin Emmanuel Oluokun","doi":"10.1186/s12866-024-03660-3","DOIUrl":"10.1186/s12866-024-03660-3","url":null,"abstract":"<p><strong>Background: </strong>Staphylococcus aureus strains are highly virulent and associated with an eclectic range of severe nosocomial and community-acquired infections.</p><p><strong>Objectives: </strong>This study assessed methicillin- and vancomycin-resistant Staphylococcus aureus (MRSA/VRSA) from clinical and ready-to-eat (RTE) food sources, screened for antibiotic resistance; and molecular determinants of antibiotic and virulence genes.</p><p><strong>Methods: </strong>Altogether, 465 clinical and RTE food samples were analyzed via conventional microbiological techniques and S. aureus identification was confirmed by nuc gene detection. Phenotypic screening for methicillin and vancomycin-resistance was by agar-screen cum micro-broth dilution respectively, while antibiotic susceptibility testing was done by the disc-diffusion technique. VanA/vanB/VanC1, femA, mecA/mecC; pvl/hlg and spa gene detection was via Polymerase chain reaction.</p><p><strong>Results: </strong>Phenotypically, 211 Staphylococcal isolates were recovered, 138 (65.4%) of them carrying the nuc gene - all 138 (100.0%) were VRSA, while 59/138 (42.8%) were MRSA phenotypically. Overall, 114/138 (82.6%), 7/138 (5.1%), and 6/138 (4.3%) of isolates had the femA, mecA, and mecC genes, while van genes were detected in only 3 (2.2%) isolates, with virulence determinants pvl, hlg, and spa gene carriage in 8 (5.8%), 10 (7.2%), and 77 (55.8%) isolates respectively. In all, 11.6% carried resistance-associated genes, 55.8% carried virulence genes, and co-detection of resistance and virulence genes was observed in 12.3%. Overall, 96/138 (69.6%) were multidrug-resistant (MDR), while one strain was extremely drug-resistant (XDR). MAR Indices ≥ 0.2 was observed in 83.3% of isolates.</p><p><strong>Conclusion: </strong>This study highlights virulence levels of MRSA and VRSA circulating strains in Osogbo, contributing to their sustained surveillance, and improving available data for successive epidemiology investigations. This study also reports the occurrence of the mecC gene in S. aureus isolates from RTE foods and human samples in Southwestern Nigeria.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"498"},"PeriodicalIF":4.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11590366/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142725665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal dynamics of soil microbiome in response to dry-wet alternation along the Jinsha River Dry-hot Valley.","authors":"Hao Jiang, Xiaoqing Chen, Yongping Li, Jiangang Chen, Li Wei, Yuanbin Zhang","doi":"10.1186/s12866-024-03662-1","DOIUrl":"10.1186/s12866-024-03662-1","url":null,"abstract":"<p><strong>Background: </strong>Soil microorganisms play a key role in nutrient cycling, carbon sequestration, and other important ecosystem processes, yet their response to seasonal dry-wet alternation remains poorly understood. Here, we collected 120 soil samples from dry-hot valleys (DHVs, ~ 1100 m a.s.l.), transition (~ 2000 m a.s.l.) and alpine zones (~ 3000 m a.s.l.) along the Jinsha River in southwest China during both wet and dry seasons. Our aims were to investigate the bacterial microbiome across these zones, with a specific focus on the difference between wet and dry seasons.</p><p><strong>Results: </strong>Despite seasonal variations, bacterial communities in DHVs exhibit resilience, maintaining consistent community richness, diversity, and coverage. This suggests that the microbes inhabiting DHVs have evolved adaptive mechanisms to withstand the extreme dry and hot conditions. In addition, we observed season-specific microbial clades in all sampling areas, highlighting their resilience to environmental fluctuations. Notably, we found similarities in microbial clades between soils from DHVs and the transition zones, including the phyla Actinomycetota, Chloroflexota, and Pseudomonadota. The neutral community model respectively explained a substantial proportion of the community variation in DHVs (87.7%), transition (81.4%) and alpine zones (81%), indicating that those were predominantly driven by stochastic processes. Our results showed that migration rates were higher in the dry season than in the wet season in both DHVs and the alpine zones, suggesting fewer diffusion constraints. However, this trend was reversed in the transition zones.</p><p><strong>Conclusions: </strong>Our findings contribute to a better understanding of how the soil microbiome responds to seasonal dry-wet alternation in the Jinsha River valley. These insights can be valuable for optimizing soil health and enhancing ecosystem resilience, particularly in dry-hot valleys, in the context of climate change.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"496"},"PeriodicalIF":4.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11587743/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142715407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative genomics analysis of Salmonella Enteritidis isolated from clinical cases associated with chicken.","authors":"Xiangfeng Bu, Yufan Wu, Yi Hong, Juping Shi, Jingdong Shao, Kai Jia, Qingli Dong, Xiang Wang","doi":"10.1186/s12866-024-03651-4","DOIUrl":"10.1186/s12866-024-03651-4","url":null,"abstract":"<p><p>Salmonella Enteritidis is a major foodborne pathogen, and the emergence of multidrug-resistant (MDR) S. Enteritidis poses a serious public health challenge. In this study, we report the genomic characterization of five S. Enteritidis isolates from clinical. These isolates exhibited resistance to seven classes of antimicrobials with four of the five characterized as MDR. Isolate 33 A exhibited resistance to colistin and polymyxin B, while no associated antimicrobial resistance genes (ARGs) were identified in its genome. Isolate 21 A and 44 A were extended-spectrum beta-lactamases-producing (ESBLs). Whole genome sequencing analysis revealed the presence of multiple mobile genetic elements (MGEs), including plasmids, prophages, and genomic islands, which may have facilitated the acquisition and dissemination of ARGs. Notably, several ARGs, including bla_CTX-M-55, bla_TEM-141, bla_TEM-1B, aph(3')-IIa, aph(3'')-Ib, aph(6)-Id, tet(A), floR, fosA3, and sul2, were identified on plasmids. In addition, chromosomal point mutations in gyrA (D87G and D87Y) and acrB (F28L and L40P) were also observed in each isolate. Multiple virulence genes associated with the type III secretion system were identified on Salmonella pathogenicity islands (SPIs) SPI-1 and SPI-2. Phylogenetic analysis revealed that the five isolates, along with a clinical and chicken origin isolates in the database, clustered together, suggesting a probable common source of infection. Our findings highlight the intricate genetic mechanisms behind MDR in S. Enteritidis, emphasizing the ongoing necessity for surveillance and appropriate antimicrobial usage. This contributes to our understanding of S. Enteritidis transmission within the food chain.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"497"},"PeriodicalIF":4.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11587697/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142715405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of Serratia marcescens (OK482790)' prodigiosin along with in vitro and in silico validation for its medicinal bioactivities.","authors":"Marwa A Hamada, Eslam T Mohamed","doi":"10.1186/s12866-024-03634-5","DOIUrl":"10.1186/s12866-024-03634-5","url":null,"abstract":"<p><strong>Background: </strong>Microbial prodigiosin pigment has been proposed as a promising biomolecule having an antibacterial, immunosuppressive, antimalarial, antineoplastic, and anticancer activities. The good outcome originates from getting natural pigment, which has many medical applications.</p><p><strong>Results: </strong>In this investigation, prodigiosin (PG) was extracted, characterized by UV-visible spectroscopy, thin-layer chromatography, mass spectroscopy, Fourier-transform infrared spectroscopy, and tested in various medical applications as an antibacterial, antioxidant, antibiofilm, anticancer, and wound healing agent at different concentrations. Antibacterial activity of PG pigment was shown against both Gram-positive and Gram-negative bacterial strains. Enterococcus faecalis was the most severely impacted, with minimum inhibitory value of 3.9 µg/mL. The formed biofilm by Pseudomonas aeruginosa was suppressed by 58-2.50% at prodigiosin doses ranging from 1000 to 31.25 µg/mL, respectively. The half-maximal inhibitory concentration (IC₅₀) of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) free radical was 74.18 ± 23.77 µg/mL. At 100 µg/mL concentration, OK482790 prodigiosin had no harmful effect on normal skin cells and exhibited mild wound healing properties. Additionally, molecular docking simulations confirmed the prodigiosin's interactions with target proteins, including epidermal growth factor receptor tyrosine kinase (EGFR-TK, PDB ID: 1M17), peptide deformylase from E. faecalis (PDB ID: 2OS1), acidic fibroblast growth factor (FGF-1, PDB ID: 3K1X), PA14_16140 protein from P. aeruginosa (PDB ID: 8Q8O), and human peroxiredoxin 5 (PDB ID: 1HD2) for explaining the anticancer, antibacterial, wound healing, antibiofilm, and antioxidant activities, respectively. Prodigiosin had favorable binding affinities and putative modes of action across various therapeutic domains.</p><p><strong>Conclusion: </strong>This study pioneers the use of prodigiosin as a natural alternative to synthetic medicine since it fights germs, heals wounds, is antioxidant, and reduces biofilm formation.</p><p><strong>Clinical trial number: </strong>Not applicable.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"495"},"PeriodicalIF":4.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11587630/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142715404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interpretation of bacterial composition patterns and community assembly processes in the rhizosphere soil of tea trees in karst areas.","authors":"Yuanqi Zhao, Ni Zhang, Jiajia Chen, Weiwei Ran, Zhibing Zhao, Yuehua Song","doi":"10.1186/s12866-024-03658-x","DOIUrl":"10.1186/s12866-024-03658-x","url":null,"abstract":"<p><strong>Research background and purpose: </strong>Soil microorganisms that are closely related to plants are important factors affecting plant health. Therefore, elucidating the abundant and rare bacterial species in soil associated with plant diseases is crucial for understanding ecological processes, maintaining the stability of microecological environments, and formulating microbial strategies that are consistent with modern agricultural development.</p><p><strong>Results: </strong>Tea leaf blight leads to an increase in bacterial diversity in the rhizosphere. Random processes dominate the assembly of abundant and rare taxa, while abundant taxa are also influenced by deterministic processes. In the co-occurrence network, the increase in bacterial community diversity mediated by tea cloud leaf blight enhances the stability of the network. Meanwhile, the proportion of positive correlation between rare taxa is relatively high, and the relationship between rare taxa and intermediate taxa is closer. This highly diverse bacteria community maintained the structure and stability of the community to a certain extent.</p><p><strong>Conclusion: </strong>The rare taxa in the rhizosphere and the rhizosphere bacterial community mediated by tea leaf blight have high diversity, which is of great significance for maintaining the stability of the rhizosphere bacterial ecological network. In the future, we will further explore the dynamic changes and interaction patterns of the species in the rhizosphere soil affected by tea tree diseases, and their ecological functions and importance in areas of habitat fragmentation. Overall, there are many microbial resources in the rhizosphere microbiota under the influence of plant diseases that can be used for agricultural practice. The results of this study will enrich the insights into ecodynamics of bacteria in karst areas, especially in karst tea gardens.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"492"},"PeriodicalIF":4.0,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11585092/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142692657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of flue-curing and redrying on the diversity of fungal communities in tobacco leaves.","authors":"Yue Yang, Gaowei Pan, Jianhua Guo, Chenlin Miao, Qiang Xu, Yifan Zhang, Mengmeng Yang, Chaoqun Xue, Liwei Hu, Zongyu Hu","doi":"10.1186/s12866-024-03635-4","DOIUrl":"10.1186/s12866-024-03635-4","url":null,"abstract":"<p><p>Flue-curing and redrying are important processing stages before tobacco fermentation, closely linked to microbial actions that influence the fermentation process. It is necessary to investigate the effects of flue-curing and redrying on diversity and succession of tobacco fungal communities. It was shown that a total of 9 phyla, 33 classes, 94 orders, 266 families, 646 genera, and 6,396 amplicon sequence variants (ASVs) were identified in the fungi communities of 36 samples from different processing stages (before flue-curing, after flue-curing, before redrying and after redrying) based on high-throughput sequencing technology. Dominant genera shared by tobacco leaves at different stages were Alternaria and Sampaiozyma. About 80% of fungi in stored tobacco leaves after redrying originated from fresh tobacco leaves before flue-curing, while the rest were primarily enriched in the post-harvest processing environment. After flue-curing, major molds like Aspergillus and Penicillium were notably enriched. The distribution of fungal communities suggested that the flue-curing and redrying had a significant impact on fungal composition. Functional annotation of fungal communities at the guild level exhibited differences during processing stages. Main fungal functional groups were identified. In summary, our study elucidated dynamic changes in the composition of fungal communities and highlighted key stages in mold enrichment during tobacco leaf processing, laying groundwork for mildew prevention and control during tobacco leaf fermentation.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"494"},"PeriodicalIF":4.0,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11585231/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142695268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Saccharomyces boulardii on microbiota composition and metabolite levels in the small intestine of constipated mice.","authors":"Shuai Tang, Jia Li, Yi Li, Haitao Du, Wenya Zhu, Ru Zhang, Jun Wan","doi":"10.1186/s12866-024-03647-0","DOIUrl":"10.1186/s12866-024-03647-0","url":null,"abstract":"<p><p>Saccharomyces boulardii (S. boulardii) is a fungal probiotic used to treat digestive disorders. However, the mechanism(s) by which S. boulardii affects the small intestine remains unclear. Here, we aimed to explore the effects of S. boulardii on the small intestine and the underlying mechanisms in mice with loperamide-induced constipation. While S. boulardii administration did not fully reverse the alterations in loperamide-induced defecation parameters, it altered the small intestinal floral composition toward a community conducive to alleviate constipation. Moreover, S. boulardii up-regulated the expression of tyrosine-protein kinase Kit (c-Kit), aquaporin 3 (AQP3), interleukin (IL)-10, myosin light chain kinase (MLCK), and phosphorylated myosin light chain 20 (P-MLC20), while concurrently down-regulating the expression levels of inducible nitric oxide synthase (iNOS), p65, and IL-17 A. These alterations indicate a discernible effect of small intestinal water reabsorption, inflammatory factor levels, and smooth muscle contraction. Saccharomyces boulardii also positively regulated small intestinal metabolite levels, such as fructose 6-phosphate, dihomo-alpha-linolenic acid, and 3-(4-hydroxyphenyl) lactate, and participated in metabolic pathways such as arginine biosynthesis, linoleic acid metabolism, and protein digestion and absorption. While not fully reversing defecation changes, Saccharomyces boulardii alters intestinal flora, up-regulates key proteins affecting water reabsorption and inflammation, and positively influences metabolic pathways. Our study provides serves as a basis for further studies on the application of S. boulardii in the treatment of intestinal disorders.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"493"},"PeriodicalIF":4.0,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11585213/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142692639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Complete genome sequencing of Enterobacter ludwigii strain T977 revealed its great ability for starch degradation of Nicotiana tabacum L. Yunyan 97.","authors":"Liwei Hu, Qin Gao, Yuan Ji, Xiangzhou Dong, Qifa Zhu, Tingming Cheng, Limei Zhao, Mengmeng Yang, Zhen Zhai, Huaxin Dai, Taibo Liang, Chaoqun Xue","doi":"10.1186/s12866-024-03613-w","DOIUrl":"10.1186/s12866-024-03613-w","url":null,"abstract":"<p><p>Enterobacter ludwigii has been proven by numerous studies to be an effective plant growth promoter. Enterobacter ludwigii T977 was isolated from leaves of Nicotiana tabacum L. Yunyan 97 which showing high starch degrading ability. The optimal fermentation carbon source of strain T977 was starch, with optimal starch concentration as 2.5 g/L, and the most suitable fermentation nitrogen source for the strain T977 was ammonium acetate, with optimal concentration as 0.25 g/L. The spaying treatment of strain T977 could reduce the starch content of upper leaves from 3.77% to 1.43%, the total sugar and reducing sugar decreased slightly, the starch content of middle leaves decreased from 5.63% to 3.18%, the content of total sugar and reducing sugar increased in middle leaves, and the other chemical components were in the appropriate range. Here, we reported 4.77 MB whole genome of a starch-degrading E. ludwigii T977 that encodes 4501 proteins, 11 α-amylases in GH13 family were identified, and the amylase (GM000159) with signal peptide may play important role in degradation of starch in tobacco leaves. Our study may provide an effective microbiological mean for reducing starch content in tobacco leaves.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"491"},"PeriodicalIF":4.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11583658/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142692637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of non-O157 enterohemorrhagic Escherichia coli isolated from different sources in Egypt.","authors":"Omnia T Bahgat, Dina E Rizk, Hany I Kenawy, Rasha Barwa","doi":"10.1186/s12866-024-03636-3","DOIUrl":"10.1186/s12866-024-03636-3","url":null,"abstract":"<p><strong>Background: </strong>Enterohemorrhagic Escherichia coli (EHEC) O157 is implicated in serious food and water-borne diseases as hemorrhagic colitis (HC), and the potentially fatal hemolytic uremic syndrome (HUS). However, new players of non-O157 EHEC have been implicated in serious infections worldwide. This work aims at analyzing serotype and genotypic-based virulence profile of EHEC local isolates.</p><p><strong>Methods: </strong>A total of 335 samples were collected from different sources in Egypt. E. coli was isolated and subjected to serotyping. Non-O157 EHEC isolates were tested for virulence genes using PCR, phenotypic examination, phylogenetic typing, and molecular investigation by ERIC typing and MLST to disclose genetic relatedness of isolates. A heat map was used to identify potential associations between the origin of the isolates, their phenotypic and genotypic characteristics.</p><p><strong>Results: </strong>A total of 105 out of 335 isolates were identified as E. coli. Surprisingly, 49.5% of these isolates were EHEC, where O111, O91, O26 and O55 were the most prevalent serotypes including 38.46% from stool, 21.15% urine, 23.1% cheese, 9.62% meat products, 3.85% from both yogurt and sewage water. Screening 15 different virulence genes revealed that sheA, stx2 and eae were the most prevalent with abundance rates of 85%, 75% and 36%, respectively. Fifteen profiles of virulence gene association were identified, where the most abundant one was stx2/sheA (19%) followed by stx2/stx2g/sheA/eae (11.5%). Both stx2/sheA/eae and stx2/stx2g/sheA were equally distributed in 9.6% of total isolates. Phylogenetic typing revealed that pathogenic phylogroups B2 and D were detected among clinical isolates only. Forty-six different patterns were detected by ERIC genotyping. MLST resolved three sequence types of ST70, ST120 and ST394. The heat map showed that 21 isolates were of 70% similarity, 9 groups were of 100% clonality.</p><p><strong>Conclusions: </strong>The prevalence of non-O157 EHEC pathotype was marginally higher among the food isolates compared to the clinical ones. The endemic ST120 was detected in cheese, necessitating crucial measures to prevent the spread of this clone. Clinical EHEC isolates exhibited a higher score, and combination of virulence genes compared to food and sewage water isolates, thereby posing a significant public health concern.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"488"},"PeriodicalIF":4.0,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11580514/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142686159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical quantification of N-acyl alanine methyl ester (NAME) production and impact on temporal gene expression patterns in Roseovarius tolerans EL-164.","authors":"Janina Leinberger, Diana Koteska, Judith Boldt, Jörn Petersen, Sahana Shivaramu, Jürgen Tomasch, Stefan Schulz, Thorsten Brinkhoff","doi":"10.1186/s12866-024-03624-7","DOIUrl":"10.1186/s12866-024-03624-7","url":null,"abstract":"<p><strong>Background: </strong>Previous studies have identified structurally diverse N-acyl amino acid methyl esters (NAMEs) in culture extracts of Roseovarius tolerans EL-164 (Roseobacteraceae). NAMEs are structural analogues of the common signaling compounds N-acyl homoserine lactones (AHLs), but do not participate in AHL-mediated signaling. NAMEs show minor antialgal and antimicrobial activity, but whether this activity serves as the primary ecological role remains unclear.</p><p><strong>Results: </strong>To enable dose-dependent bioactivity-testing, we have established a chromatographic method for quantification of NAMEs in bacterial culture extracts. The concentrations determined for the two major NAMEs produced by EL-164, C16:1-NAME and C17:1-NAME, ranged between 0.685 and 5.731 mg L^- 1 (2.0-16.9 µM) and 5.3-86.4 µg L^- 1 (15.0-244.3 nM), respectively. Co-quantification of the C14:1-AHL showed concentrations ranging between 17.5 and 58.7 mg L^- 1 (56.6-189.7 µM). We observed distinct production patterns for NAMEs and AHLs, with a continuous NAME production during the entire incubation period. We conducted a spike-in experiment, using the determined metabolite concentrations. By comparing the transcriptomes of pre- and post-metabolite-spikes, we identified three clusters of differentially expressed genes with distinct temporal expression patterns. Expression levels of stress response genes differed between NAME- and AHL-spiked EL-164 cultures in the stationary phase.</p><p><strong>Conclusions: </strong>Our findings support previous studies suggesting an ecological role for C16:1-NAME as antibiotic, by proving that NAME concentrations in batch cultures were higher than the minimal inhibitory concentrations against Maribacter sp. 62 - 1 (Flavobacteriia) and Skeletonema costatum CCMP 1332 (Coscinodiscophyceae) reported in the literature. Our study further exemplified the broad application range of dose-dependent testing and highlighted the different biological activities of NAMEs and AHLs.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"489"},"PeriodicalIF":4.0,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11580390/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142686162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}