BMC Microbiology最新文献

{"title":"Current knowledge on Inquilinus limosus, a scarcely researched human pathogen.","authors":"Oluwafemi M Akinnurun, Thomas Riedel, Stephanie Müller, Boyke Bunk, Percy Schröttner","doi":"10.1186/s12866-024-03617-6","DOIUrl":"10.1186/s12866-024-03617-6","url":null,"abstract":"<p><p>Inquilinus limosus belongs to the class of the Alphaproteobacteria and was first described in 2002. So far, the species has mainly been isolated from respiratory specimens of patients with cystic fibrosis. A main characteristic of Inquilinus limosus is the prolonged time until bacterial colony growth is detectable. As the defined incubation times in many laboratories are too short to detect the growth of Inquilinus limosus, it is likely that the species is less frequently detected in the clinical setting than it actually occurs. This also explains why there are currently only very few data on the incidence available. Furthermore, as an uncommon pathogen, Inquilinus limosus may be familiar to only a few specialised clinicians. Due to these reasons, only little research (e.g. case reports and research papers) have been published on this species to date. However, given that a clear human pathogenic significance can be deduced from the existing literature, we have decided to present the current state of knowledge in this review and to address further aspects for the future elucidation of the pathogenesis of Inquilinus limosus.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"474"},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11558892/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142615086","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":"Overexpression of outer membrane protein A (OmpA) increases aminoglycoside sensitivity in mycobacteria.","authors":"Xiuling Ma, Huoming Li, Jiahong Ji, Lingyuan Zeng, Minghui Tang, Chengrui Lei, You Zuo, Hao Li","doi":"10.1186/s12866-024-03632-7","DOIUrl":"10.1186/s12866-024-03632-7","url":null,"abstract":"<p><strong>Background: </strong>Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb) complex infection, is a leading cause of death worldwide from a single infectious agent. The emergence of drug resistance Mtb clinical strains makes the situation more serious. The role of Mtb outer membrane protein A (OmpA) in antimicrobial resistance remains unclear. This study aimed to evaluate the effect of OmpA expression on mycobacterial drug resistance. In this study, a Mycobacterium smegmatis (Ms) strain overexpressing OmpA (Ms-OmpA) and a Mycobacterium bovis (Mb) strain overexpressing OmpA (Mb-OmpA) were constructed, and their susceptibility to anti-TB drugs was determined by performing the minimal inhibitory concentrations (MICs), the plate assay and the macrophage infection assays.</p><p><strong>Results: </strong>The streptomycin MIC of the overexpressing strain was 2-fold lower than those of the wide-type (Ms) and empty plasmid strains (pMV-261) as well as amikacin and gentamicin. Moreover, both the plate and the macrophage infection assays indicate that overexpression of OmpA increases streptomycin sensitivity in Mycobacteria. The other aminoglycosides like amikacin and gentamicin have the same phenotypes as streptomycin on the plates for the virulent strain Mb-OmpA. The porin inhibitor spermidine can increase streptomycin tolerance in the overexpressing strain, and overexpressing OmpA can increase the intracellular accumulation of hydrophilic ethidium bromide, which indicates that porin protein OmpA contributes to aminoglycosides sensitivity in Mycobacteria.</p><p><strong>Conclusions: </strong>In this study, we have characterized the contribution of OmpA in the antimicrobial resistance phenotype of Mycobacteria, which may provide valuable insights for understanding antibiotic resistance and designing new strategies for TB treatment.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"472"},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11558991/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142635880","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":"Continuous planting American ginseng (Panax quinquefolius L.) caused soil acidification and bacterial and fungal communities' changes.","authors":"Shaoyong Li, Haiwei Wei, Daqian Qi, Wenwen Li, Yan Dong, Fu-Ang Duan, Shou-Qing Ni","doi":"10.1186/s12866-024-03616-7","DOIUrl":"10.1186/s12866-024-03616-7","url":null,"abstract":"<p><strong>Background: </strong>American ginseng is an important herb crop and is widely cultivated in China. However, continuous cropping seriously affects the production of American ginseng, and the reason is still unclear and needs more research. We analyzed the soil microbial alpha diversity and community composition as well as soil physicochemical properties in bulk soils to assess the changes in soil associated with planting American ginseng.</p><p><strong>Results: </strong>The cultivation of American ginseng resulted in a significant decrease in soil pH value. The alpha diversity of soil bacteria and fungi was significantly reduced with the increase of American ginseng planting years. Planting American ginseng also largely altered the community composition of soil bacteria and fungi, in particularly, increased the relative abundance of the pathogenic fungus Fusarium, and reduced the relative abundance of some beneficial microorganisms, such as KD4-96, RB41 and Sphingomonas.</p><p><strong>Conclusions: </strong>Soil acidification, reduction of beneficial taxa and accumulation of fungal pathogens, therefore, may lead to the replantation problem of American ginseng.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"473"},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11559190/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142615080","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":"Bacterial community in fresh fruits and vegetables sold in streets and open-air markets of Dakar, Senegal.","authors":"Sarbanding Sane, Sophie Deli Tene, Abou Abdallah Malick Diouara, Seynabou Coundoul, Malick Mbengue, Yakhya Dieye","doi":"10.1186/s12866-024-03622-9","DOIUrl":"10.1186/s12866-024-03622-9","url":null,"abstract":"<p><p>In the context of food transition, the agrifood sector has experienced increasingly strong demand for horticultural products. Fresh fruits and vegetables are mainly vehicles of microorganisms, including pathogens that cause human infections. Food safety and compliance with health standards in the fruits and vegetable value chain are significant concerns and multiple challenges, given the prevalence of foodborne pathologies in Southern countries, particularly in Senegal. This study aimed to describe the bacterial community and assess the microbiological quality of a range of fruits and vegetables sold on street stalls and open-air markets in Dakar, the capital city of Senegal. Samples purchased in seven sites were analyzed to isolate Escherichia coli (E. coli), Salmonella spp. and Vibrio spp. Some primary samples with a positive microbiological culture were subjected to DNA extraction and subsequent metagenomic analysis. A total of 240 fresh fruit and vegetable samples were collected, including lettuce (n = 40), tomatoes (n = 40), mango slices (n = 40), onion slices (n = 40), mint leaves (n = 40), strawberries and grapes (each n = 20). Of these samples, 50.83% (122/240) and 60.41% (145/240) were contaminated with E. coli and Vibrio spp., respectively, while Salmonella was not isolated in any product. E. coli and Vibrio spp. contamination levels, 1.3 10³ to 6 10⁶ Colonies Forming Units per gram of sample (CFU/g) and 4.55 10² to 8.73 10⁶ CFU/g, respectively, were significantly above the thresholds acceptable for human consumption. The most contaminated samples were lettuce, with a prevalence of 98% (39/40) for E. coli and Vibrio spp. followed by mint leaves with 100% (40/40) and 93% (37/40) of the samples containing E. coli and Vibrio spp. respectively. Out of 46 samples sequenced, the metagenomic analysis revealed high contamination rates for E. coli, Vibrio spp. and Salmonella spp., with 100%, 67.39% and 93.47% of prevalence, respectively. On the other hand, the alpha diversity analysis shows high bacterial diversity in lettuce and mint leaf samples, while the beta diversity analysis highlighted the presence of two major clusters. Our results stress the need for a surveillance system that extends this investigation to a national scale while increasing the number of sampling sites and products analyzed.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"471"},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11559176/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142615056","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":"Comparison of microbial diversity and carbohydrate-active enzymes in the hindgut of two wood-feeding termites, Globitermes sulphureus (Blattaria: Termitidae) and Coptotermes formosanus (Blattaria: Rhinotermitidae).","authors":"Zhidong Zhang, Kai Wang, Chuanshan Zou, Ting Zhao, Wenbin Wu, Cai Wang, Yan Hua","doi":"10.1186/s12866-024-03623-8","DOIUrl":"10.1186/s12866-024-03623-8","url":null,"abstract":"<p><strong>Background: </strong>Wood-feeding termites have been employed as sources of novel and highly efficient lignocellulolytic enzymes due to their ability to degrade lignocellulose efficiently. As a higher wood-feeding termite, Globitermes sulphureus (Blattaria: Termitidae) plays a crucial role as a decomposer in regions such as Vietnam, Singapore, Myanmar, and Yunnan, China. However, the diversity of its gut microbiome and carbohydrate-active enzymes (CAZymes) remains unexplored. Here, we analyzed the diversity of hindgut microbial communities and CAZymes in a higher wood-feeding termite, G. sulphureus, and a lower wood-feeding termite, Coptotermes formosanus (Blattaria: Rhinotermitidae).</p><p><strong>Results: </strong>16S rRNA sequencing revealed that Spirochaetota, Firmicutes, and Fibrobacterota were the dominant microbiota in the hindgut of the two termite species. At the phylum level, the relative abundances of Proteobacteria and Bacteroidota were significantly greater in the hindgut of C. formosanus than in G. sulphureus. At the genus level, the relative abundances of Candidatus_Azobacteroides and Escherichia-Shigella were significantly lower in the hindgut of G. sulphureus than in C. formosanus. Metagenomic analysis revealed that glycoside hydrolases (GHs) with cellulases and hemicellulases functions were not significantly different between G. sulphureus and C. formosanus. Interestingly, the cellulases in G. sulphureus were mainly GH5_2, GH5_4, GH6, GH9, and GH45, while the hemicellulases were mainly GH11, GH8, GH10, GH11, GH26, and GH53. In C. formosanus, the cellulases were mainly GH6 and GH9, and the hemicellulases were mainly GH5_7, GH5_21, GH10, GH12, and GH53. In addition, β-glucosidase, exo-β-1,4-glucanase, and endo-β-1,4-glucanase activities did not differ significantly between the two termite species, while xylanase activity was higher in G. sulphureus than in C. formosanus. The bacteria encoding GHs in G. sulphureus were mainly Firmicutes, Fibrobacterota, and Proteobacteria, whereas Bacteroidota and Spirochaetota were the main bacteria encoding GHs in C. formosanus.</p><p><strong>Conclusions: </strong>Our findings characterized the microbial composition and differences in the hindgut microbiota of G. sulphureus and C. formosanus. Compared to C. formosanus, G. sulphureus is enriched in genes encoding for hemicellulase and debranching enzymes. It also highlights the rich diversity of GHs in the hindgut microbiota of G. sulphureus, including the GH5 subfamily, GH6, and GH48, with the GH6 and GH48 not previously reported in other higher termites. These results strengthen the understanding of the diversity of termite gut microbiota and CAZymes.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"470"},"PeriodicalIF":4.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11556000/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142615065","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":"Hydrogen-rich water 400ppb as a potential strategy for improving ruminant nutrition and mitigating methane emissions.","authors":"Kang Mao, Guwei Lu, Yitian Zang, Qinghua Qiu, Xianghui Zhao, Kehui Ouyang, Mingren Qu, Yanjiao Li","doi":"10.1186/s12866-024-03638-1","DOIUrl":"10.1186/s12866-024-03638-1","url":null,"abstract":"<p><p>The objective of this study was to evaluate the effects of different concentrations of hydrogen-rich water (HRW) on in vitro rumen fermentation characteristics and the dynamics of bacterial communities. The experiment included four treatment groups: a control (CON) and hydrogen-rich water (HRW) at 200, 400, and 800 ppb. Each group was analyzed at 12-hour (h) and 48-hour (h) time points with five replicates, totaling 40 samples. The experimental results highlighted the HRW_800ppb group as the top production in terms of gas production and CH₄ content. In contrast, the HRW_200ppb group exhibited significantly lower methane levels at both 12 h and 48 h (P < 0.05). Regarding rumen fermentation, the HRW_400ppb group significantly increased the levels of ammonia nitrogen (NH₃-N) and microbial crude protein (MCP) at 12 h fermentation, but reduced the dry matter degradation rate (P < 0.05). After 48 h, the HRW_400ppb group had highest MCP content (P < 0.05), but no significant differences in NH₃-N and dry matter degradation rate compared with the CON group (P > 0.05). Although HRW did not significantly benefit the synthesis of total volatile fatty acids (TVFA) and individual VFA, the HRW_800ppb group significantly increased the ratio of acetate to propionate (P < 0.05). Based on CH₄ emissions and MCP synthesis, we selected the HRW_400ppb group for subsequent bacterial community analysis. Bacterial community analysis showed that at 12 h, compared with the CON group, the Bacterial community analysis revealed that the HRW_400ppb group had significant increases in the Simpson index, Firmicutes, Streptococcus, Schwartzia, Prevotellaceae_YAB2003_group, and Oribacterium, and decreases in Prevotella, Ruminobacter, Succinivibrio, unclassified_Succinivibrionaceae, and Prevotellaceae_UCG-003 (P < 0.05). At 48 h, the Prevotellaceae_YAB2003_group and Oribacterium abundances continued to rise significantly, while Rikenellaceae_RC9_gut_group and Succiniclasticum abundances fell in the HRW_400ppb group (P < 0.05). Correlation analysis indicated a negative link between CH₄ and Streptococcus, and a positive correlation between the abundance of Rikenellaceae_RC9_gut_group and CH₄. Collectively, these results indicate that HRW can modulate rumen fermentation and microbial community structure to reduce methane emissions without significantly affecting VFA synthesis, highlighting its potential as drinking water for enhancing ruminant nutrition and mitigating the environmental impact of livestock farming.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"469"},"PeriodicalIF":4.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11555914/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142615104","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":"Emergence of hypervirulent and carbapenem-resistant Klebsiella pneumoniae from 2014 - 2021 in Central and Eastern China: a molecular, biological, and epidemiological study.","authors":"Chunyang Wu, Yu Huang, Peiyao Zhou, Haojin Gao, Bingjie Wang, Huilin Zhao, Jiao Zhang, Liangxing Wang, Ying Zhou, Fangyou Yu","doi":"10.1186/s12866-024-03614-9","DOIUrl":"10.1186/s12866-024-03614-9","url":null,"abstract":"<p><strong>Background: </strong>In recent years, the hypervirulent and carbapenem-resistant Klebsiella pneumoniae has been increasingly reported worldwide. The objective of this study was to compare the antibiotic resistance and virulence profiles of carbapenem-resistant hypervirulent K.pneumoniae (CR-hvKP) and hypervirulent carbapenem-resistant K.pneumoniae (hv-CRKP) and identify the prevailing strain in clinical settings.</p><p><strong>Methods: </strong>In this study, hv-CRKP or CR-hvKP were identified based on the results of whole-genome analysis (WGS), multilocus sequence typing (MLST) and the antimicrobial susceptibility testing. We then compared antibiotic resistance and virulence profiles between CR-hvKP and hv-CRKP through the antimicrobial susceptibility testing and a series of virulence experiments including biofilm formation ability detection method, the resistance test against human serum, siderophore production test, neutrophil phagocytosis assay and Galleria mellonella infection model. Additionally, pathway enrichment analysis was conducted to assess the effect of SNPs on the phenotype.</p><p><strong>Results: </strong>In this study, we categorized 17.4% of hypervirulent and carbapenem-resistant K. pneumoniae strains as CR-hvKP and 82.6% as hv-CRKP. Among them, 84.2% (16/19) of CR-hvKP strains harboring carbapenemase genes exhibited lower imipenem and meropenem MIC values compared to hv-CRKP strains. The virulence potential of hv-CRKP and CR-hvKP was confirmed by using virulence experiments in vitro and in vivo, showing that virulence of the CR-hvKP strains was comparable to that of hv-CRKP strains. Notably, the 90 hv-CRKP strains were classified into 3 different ST types and 8 capsule types, each showing varying degrees of resistance and virulence. We observed that subclonal replacement was within the predominant hv-CRKP clone, with the ST11-KL64 strain, characterized by high-level resistance and virulence emerging as the currently prevailing subclone, replacing ST11-KL47. KEGG enrichment analysis showed that pathways associated with the citrate cycle (TCA cycle), glycolysis/gluconeogenesis, glutathione metabolism, two-component regulatory system, and folate metabolism were significantly enriched among the group expressing different levels of capsular polysaccharides.</p><p><strong>Conclusions: </strong>The hv-CRKP strains exhibited a greater survival advantage in the hospital environment than CR-hvKP strains. Notably, the ST11-KL64 hv-CRKP strain which displayed a high level of resistance and hypervirulence, warrants the most clinical vigilance.</p><p><strong>Clinical trial number: </strong>Not applicable.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"465"},"PeriodicalIF":4.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11552131/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142615100","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":"Impact of TiO₂, ZnO, and Ag nanoparticles on anammox activity in enriched river Nile sediment cultures: unveiling differential effects and environmental implications.","authors":"Mohamed A Abd El-Aziz, Ali M Saeed, Mohamed K Ibrahim, Wael S El-Sayed","doi":"10.1186/s12866-024-03603-y","DOIUrl":"10.1186/s12866-024-03603-y","url":null,"abstract":"<p><strong>Background: </strong>The increasing use of nanoparticles (NPs) necessitates investigation of their impact on wastewater treatment processes, particularly anammox, a critical biological nitrogen removal pathway. This study explored the effects of short-term exposure to TiO₂, ZnO, and Ag-NPs on anammox activity in enriched cultures derived from River Nile sediments.</p><p><strong>Materials and methods: </strong>Anammox bacteria were identified and enriched, with activity confirmed through 16S rRNA and hydrazine oxidoreductase (hzo) gene amplification and sequencing. Activity assays demonstrated efficient ammonium removal by the enriched culture. Subsequently, the impact of different sized and concentrated NPs on anammox activity was assessed.</p><p><strong>Results: </strong>XRD analysis confirmed NP behavior within the microcosms: TiO₂ transformed, ZnO partially dissolved, and Ag remained ionic. hzo gene expression served as a biomarker for anammox bacterial activity. Interestingly, 100 nm TiO₂-NPs up-regulated hzo expression, potentially indicating a non-inhibitory transformed phase. Conversely, ZnO and Ag-NPs across all sizes and concentrations significantly down-regulated hzo expression, suggesting detrimental effects. Ag-NPs amended microcosms showed a significant reduction (79%) in hzo gene expression and a detrimental effect on bacterial populations. Overall, anammox activity mirrored hzo expression patterns, with TiO₂ (21 and 25 nm, respectively) exhibiting the least inhibition, followed by ZnO and Ag-NPs.</p><p><strong>Conclusion: </strong>This study highlights the differential effects of NPs on anammox, with the order of impact being Ag > ZnO > TiO₂. These findings provide valuable insights into the potential environmental risks of NPs on anammox-mediated nitrogen cycling in freshwater ecosystems.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"468"},"PeriodicalIF":4.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11552349/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142615117","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":"Co-existence of antibiotic resistance and virulence factors in carbapenem resistant Klebsiella pneumoniae clinical isolates from Alexandria, Egypt.","authors":"Aya T El-Kholy, Mohammed A El-Kholy, Hoda Omar, Elsayed Aboulmagd","doi":"10.1186/s12866-024-03600-1","DOIUrl":"10.1186/s12866-024-03600-1","url":null,"abstract":"<p><strong>Background: </strong>The emergence and spread of carbapenem resistance among Enterobacteriaceae, particularly Klebsiella pneumoniae, constitute a serious threat to public health, since carbapenems are the last line of defense in the treatment of life-threatening infections caused by drug-resistant Enterobacteriaceae. The current study investigated the co-existence of different virulence factors and carbapenemases in carbapenem-resistant Klebsiella pneumoniae clinical isolates from Alexandria, Egypt.</p><p><strong>Results: </strong>Phenotypic characterization of virulence factors indicated that 41.5% of the isolates were strong biofilm producers, while hypermucoviscosity was detected in 14.9% of the isolates. All isolates harbored five or more virulence factor encoding genes. entB, ycfM, mrkD and fimH were detected in all isolates, while only one isolate was negative for ybtS. uge, iutA, rmpA and kpn were detected in 61 (64.8%), 55 (58.5%), 41 (43.6%) and 27 (28.7%) isolates, respectively, while all isolates lacked magA and k2A. Phenotypic detection of carbapenemases was explored by performing CarbaNP and mCIM/eCIM. CarbaNP test showed positive results in 98.9% of the isolates and positive mCIM tests were observed in all isolates, while 68 (72.3%) isolates showed positive eCIM tests. bla_NDM was the most prevalent carbapenemase encoding gene (92.5%) followed by the bla_OXA-48 (51.1%), while bla_KPC was detected in only one (1.06%) isolate. bla_VIM, bla_IMP and bla_GES were not detected in any of the tested isolates.</p><p><strong>Conclusions: </strong>The widespread of carbapenem-resistant Klebsiella pneumoniae represents a major problem in health care settings. A significant association between certain virulence factors and carbapenemase-encoding genes was observed. Antibiotic stewardship programs and infection control policies should be effectively implemented especially in hospitals to limit the spread of such highly virulent pathogens.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"466"},"PeriodicalIF":4.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11552214/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142615061","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":"More powerful dysregulation of Helicobacter pylori East Asian-type CagA on intracellular signalings.","authors":"Xiaofei Ji, Zekun Sun, Hao Wu, Jianhui Zhang, Shuzhen Liu, Xinying Cao, Bin Wang, Feifan Wang, Ying Zhang, Boqing Li, Jiankai Feng, Huilin Zhao","doi":"10.1186/s12866-024-03619-4","DOIUrl":"10.1186/s12866-024-03619-4","url":null,"abstract":"<p><strong>Background: </strong>Chronic infection by Helicobacter pylori strains expressing cytotoxin-associated gene A (CagA) are the strongest risk factor for gastric cancer. CagA can be classified into East Asian-type and Western-type (CagA^E and CagA^W), with CagA^E being more closely associated with gastric cancer. This study aimed to investigate the impact of CagA^E on intracellular signaling pathways to explain its high oncogenicity.</p><p><strong>Results: </strong>Mutant H. pylori strains expressing either CagA^E or CagA^W were generated by transforming CagA^E/W-expression plasmid into CagA-deleted G27 strain (G27^ΔCagA). In human gastric epithelial cells (GES-1) infection, CagA^E induced more severe cytopathic changes, including higher interleukin-8 (IL-8) secretion, reduced cell viability, more pronounced \"hummingbird phenotype\" alterations, and increased cell migration and invasion compared to CagA^W. Transcriptome analysis revealed that CagA^E had a stronger effect on the up-regulation of key intracellular processes, including tumor necrosis factor-ɑ (TNF-ɑ) signal pathway via nuclear factor kappa-B (NF-κB), inflammatory response, interferon-γ (IFN-γ) response, hypoxia, ultraviolet (UV) response, and Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) signaling. A significant upregulation of hypoxia-related genes was a notable feature of CagA^E. GES-1 cells infected with CagA^E exhibited more severe intracellular hypoxia and higher levels of reactive oxygen species (ROS) than those infected with CagA^W. Inhibition of hypoxia-inducible factor-1α (HIF-1α), which blocks hypoxia signaling, mitigated CagA^E-induced cell migration, emphasizing the role of hypoxia in mediating CagA^E effects.</p><p><strong>Conclusions: </strong>The study provides transcriptome evidence of CagA-associated intracellular regulation during H. pylori infection, demonstrating that CagA^E exerts stronger effects on intracellular signaling than CagA^W. These findings offer insights into the heightened carcinogenic potential of CagA^E in H. pylori-induced gastric cancer.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"24 1","pages":"467"},"PeriodicalIF":4.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11552142/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142615123","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}