Moses Lorenzo Akyeh, Masatomo Morita, Sarunporn Tandhavanant, Ballamoole Krishna Kumar, Pham Hong Quynh Anh, Tran Thi Hien, Pham Tuyet Ngoc Linh, Nguyen Dong Tu, Vu Thi Mai Hien, Taichiro Takemura, Hiroyuki Terashima, Hirotaka Hiyoshi, Kazuhisa Okada, Toshio Kodama
{"title":"Virulence Potential of Nonclinical Vibrio parahaemolyticus Isolates From Vietnam: Evidence for Functional T3SS2-Mediated Enterotoxicity","authors":"Moses Lorenzo Akyeh, Masatomo Morita, Sarunporn Tandhavanant, Ballamoole Krishna Kumar, Pham Hong Quynh Anh, Tran Thi Hien, Pham Tuyet Ngoc Linh, Nguyen Dong Tu, Vu Thi Mai Hien, Taichiro Takemura, Hiroyuki Terashima, Hirotaka Hiyoshi, Kazuhisa Okada, Toshio Kodama","doi":"10.1111/1348-0421.13229","DOIUrl":"10.1111/1348-0421.13229","url":null,"abstract":"<div>\u0000 \u0000 <p><i>Vibrio parahaemolyticus</i> is a leading cause of seafood-borne gastroenteritis worldwide, and its pathogenic strains typically harbor thermostable direct hemolysin (TDH) and type III secretion system 2 (T3SS2). Although these virulence factors are associated primarily with clinical isolates, their presence in nonclinical environmental and food isolates raises concerns about their potential infection risk. In this study, we investigated the pathogenic potential of nonclinical <i>V. parahaemolyticus</i> isolates from Vietnam, which share serotypic and genotypic characteristics with pandemic strains. Serotyping and genetic analysis of 56 isolates (35 clinical and 21 nonclinical) revealed that two nonclinical isolates from shrimp and environmental water carried the <i>tdh</i> gene, T3SS2α genes, and pandemic markers that clustered phylogenetically with the pandemic strains. Protein expression assays confirmed that these isolates secreted TDH and the T3SS2 translocator (VopD2) at levels similar to those in the clinical reference strain. Bile exposure induced T3SS2-related gene expression, which suggests a conserved gene regulatory mechanism. Enterotoxicity evaluated using a rabbit ileal loop assay showed that two nonclinical isolates induced significant fluid accumulation. Genetic deletion and complementation experiments confirmed that T3SS2 was essential for enterotoxicity. These findings provide the first experimental evidence that nonclinical pandemic strains of <i>V. parahaemolyticus</i> possess functional enteric virulence mechanisms and suggest their potential as infection sources in endemic regions.</p></div>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":"69 8","pages":"429-445"},"PeriodicalIF":1.8,"publicationDate":"2025-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144528897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bifidobacterium bifidum G9-1 Survives in the Intestinal Environment and Influences the Gut Microbiota Despite the Presence of Antimicrobials","authors":"Haruka Yokota, Yutaka Makizaki, Yoshiki Tanaka, Hiroshi Ohno","doi":"10.1111/1348-0421.13230","DOIUrl":"10.1111/1348-0421.13230","url":null,"abstract":"<p>Probiotics can help prevent antibiotic-associated diarrhea; however, those lacking antimicrobial resistance may be ineffective during antimicrobial treatment. Here, we aimed to examine the effects of antimicrobials on the probiotic strain <i>Bifidobacterium bifidum</i> G9-1 (BBG9-1). Minimum inhibitory concentrations were determined in vitro by culturing <i>B. bifidum</i> G9-1 with antimicrobials and assessing its viability. For in vivo analysis, germ-free and specific pathogen-free mice were administered <i>B. bifidum</i> G9-1 along with antimicrobials. Gut microbiota composition and viable <i>B. bifidum</i> G9-1 abundance were determined. <i>Bifidobacterium bifidum</i> G9-1 was highly sensitive to antimicrobials in vitro. However, in a complex bacterial environment mimicking the gut environment, the abundance of viable <i>B. bifidum</i> G9-1 was significantly high despite antimicrobial exposure. Dominant bacterial populations were more affected by antimicrobials than nondominant populations, with <i>B. bifidum</i> G9-1 exhibiting increased viability in the presence of diverse bacterial species. <i>In vivo</i>, combined administration of antimicrobials and <i>B. bifidum</i> G9-1 significantly reduced <i>B. bifidum</i> G9-1 abundance in germ-free mice but not in specific pathogen-free mice, where the gut microbiota composition shifted following administration of <i>B. bifidum</i> G9-1. The presence of diverse live bacteria in the intestine promotes the survival of <i>B. bifidum</i> G9-1 and its beneficial effects, even in the presence of antimicrobials. This finding suggests that <i>B. bifidum</i> G9-1, despite lacking intrinsic antimicrobial resistance, can survive and reach the large intestine, maintaining its probiotic function. Therefore, <i>B. bifidum</i> G9-1 can potentially be used for antibiotic-associated diarrhea prevention.</p>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":"69 9","pages":"447-456"},"PeriodicalIF":1.8,"publicationDate":"2025-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1348-0421.13230","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144528896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Competitive Binding of Pseudomonas aeruginosa to Kelch-Like ECH-Associated Protein 1 Inhibits Nuclear Factor Erythroid 2-Related Factor 2 Ubiquitination and Suppresses Ferroptosis in Macrophages","authors":"Yan Zhu, Qingqing Liu, Erdan Lu, Zongyu Li","doi":"10.1111/1348-0421.13228","DOIUrl":"10.1111/1348-0421.13228","url":null,"abstract":"<div>\u0000 \u0000 <p>The survival of <i>Pseudomonas aeruginosa</i> (PA) is a major factor in causing chronic or acute lung infections in individuals with compromised immune systems. Being the initial line of defense against infections, macrophages use a variety of tactics to fight intracellular bacteria, which are intimately linked to ferroptosis. It is yet unknown, nevertheless, what function ferroptosis serves in PA-infected macrophages. Initially, we established a macrophage infection model with PA to investigate the infection levels and duration using Cell Counting Kit-8 (CCK-8) and fluorescence microscopy and assessed the intracellular quantity of PA by counting colony forming units (CFUs). Subsequently, changes in ferroptosis-related characteristics in macrophages infected with PA were detected through quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blot analysis, and fluorescence probes. Furthermore, the relationship between PA infection and ferroptosis in macrophages, as well as the specific mechanism regulating nuclear factor erythroid 2-related factor 2 (NRF2) protein stability, was validated by constructing NRF2 knockdown cells. Finally, the binding of PA to Kelch-like ECH-associated protein 1 (KEAP1) in macrophages was detected using Co-Immunoprecipitation (Co-IP) and protein thermal stability analysis. Under optimal conditions (multiplicity of infection (MOI) = 15:1, <i>t</i> = 72 h), it was demonstrated that macrophages infected with PA resisted ferroptosis, as confirmed by ferroptosis-related assays. Subsequent construction of NRF2 knockdown cells showed that PA-mediated resistance of macrophage ferroptosis depended on NRF2. Mechanistically, it was proved that PA stabilized NRF2 protein expression by inhibiting ubiquitin-proteasome-mediated protein degradation and competitively binding to KEAP1. In conclusion, this study demonstrated that PA stabilized NRF2 protein expression in macrophages, inducing resistance to ferroptosis through the ubiquitin-proteasome pathway and competitive binding to KEAP1.</p>\u0000 </div>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":"69 8","pages":"418-428"},"PeriodicalIF":1.8,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144225916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Lytic Transglycosylase Deficiency Increases Susceptibility to β-lactam Antibiotics But Reduces Susceptibility to Vancomycin in Escherichia coli","authors":"Takahiko Kimura, Kazuya Ishikawa, Ryosuke Nakagawa, Kazuyuki Furuta, Chikara Kaito","doi":"10.1111/1348-0421.13227","DOIUrl":"10.1111/1348-0421.13227","url":null,"abstract":"<p>In <i>Staphylococcus aureus</i>, a gram-positive pathogen, vancomycin-resistant strains become susceptible to β-lactam antibiotics, referred to as the “seesaw effect.” However, in gram-negative bacteria, the phenomenon is less clear. Here, we analyzed the gene-knockout effects of eight lytic transglycosylases (<i>slt, mltA, mltB, mltC, mltD, mltE, mltF, mltG</i>) on antibiotic sensitivity in <i>Escherichia coli</i>. Knockout of both <i>slt</i> and <i>mltG</i> increased sensitivity to β-lactam antibiotics and reduced sensitivity to vancomycin. The β-lactam antibiotic sensitivity and vancomycin resistance of the <i>slt</i>-knockout mutant were abolished by the introduction of the wild-type <i>slt</i> gene but remained unchanged by the introduction of the mutant <i>slt</i> gene encoding an amino acid substitution variant of the transglycosylase catalytic centre. The double-knockout strain for <i>slt</i> and <i>mltB</i> was more sensitive to ampicillin and more resistant to vancomycin than each single-knockout strain. The double-knockout strain for <i>slt</i> and <i>mltG</i> was more sensitive to ampicillin and more resistant to vancomycin than each single-knockout strain. These results suggest that loss of lytic transglycosylase activity causes β-lactam antibiotic sensitivity and vancomycin resistance in <i>E. coli</i>.</p>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":"69 8","pages":"407-417"},"PeriodicalIF":1.8,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1348-0421.13227","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144142926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Minimal Influenza Virus Transmission From Touching Contaminated Floors and Metal Door Levers: Laboratory Study II","authors":"Yuxuan Fan, Hidekazu Nishimura, Masanori Katsumi, Jie Yang, Soichiro Sakata, Masahiro Kohzuki, Satoru Ebihara","doi":"10.1111/1348-0421.13226","DOIUrl":"10.1111/1348-0421.13226","url":null,"abstract":"<div>\u0000 \u0000 <p>Influenza is generally understood to be transmitted through inhaling virus-contaminating aerosol/droplets or contact with virus-contaminated environmental surfaces (or fomites). However, the risk associated with transmission through contact with fomites is hypothetical, lacking solid quantitative evidence. In our previous paper, we demonstrated through a series of experiments that the probability of influenza virus transmission from touching contaminated surfaces of face masks is minimal (<i>Sci Rep</i> 2024, <i>14</i>, 20211). In the present study, we expanded upon this study by conducting an experimental evaluation of the likelihood of influenza transmission from dried fomites under three specific scenarios: (1) when a floor/table lies within the trajectory of artificial coughs, (2) when stainless-steel door levers are exposed to viral spraying (simulating cough), and (3) when door levers are exposed to viruses on the grasping hand. The fingertips contacting the above fomites formed on the surfaces were washed into a rinsing medium. Subsequently, we evaluated the rinsing medium for viral content using plaque-forming assay to detect the viable viruses and real-time quantitative PCR assay to detect the viral genes. We found that viable viruses were rarely transmitted to fingertips from the above fomites even when the viral loads in the viral fluid contaminating the fomites far exceeded that seen in real life. Consequently, we conclude that the probability of contact transmission of influenza via dried fomites is negligible or minimal under the scenarios studied here.</p>\u0000 </div>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":"69 7","pages":"397-406"},"PeriodicalIF":1.9,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144102011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Horizontal Gene Transfer Systems for Spread of Antibiotic Resistance in Gram-Negative Bacteria","authors":"Jun-ichi Wachino","doi":"10.1111/1348-0421.13222","DOIUrl":"10.1111/1348-0421.13222","url":null,"abstract":"<div>\u0000 \u0000 <p>Antibiotic-resistant bacteria have become a significant global threat to public health due to the increasing difficulty in treatment. These bacteria acquire resistance by incorporating various antibiotic resistance genes (ARGs) through specialized gene transfer mechanisms, allowing them to evade antibiotic attacks. Conjugation, transformation, and transduction are well-established mechanisms that drive the acquisition and dissemination of ARGs in Gram-negative bacteria. In particular, the horizontal transfer of plasmids carrying multiple ARGs is highly problematic, as it can instantly convert susceptible bacteria into multidrug-resistant ones. Transduction, mediated by bacteriophages that package ARG-containing chromosomal DNA from host cells, also plays a crucial role in ARG spread without requiring direct cell-to-cell contact. Recently, a novel horizontal gene transfer (HGT) mechanism involving outer membrane vesicles (OMVs) has been identified as a key player in ARG dissemination. OMVs—nanoscale, spherical structures produced by bacteria during growth—have been found to carry small plasmids and chromosomal DNA fragments containing ARGs from their host bacteria. This newly discovered transfer process, termed “vesiduction,” enables intercellular DNA exchange and further contributes to the spread of antibiotic resistance. Additionally, mobile genetic elements such as transposons, insertion sequences, and site-specific recombination systems like integrons facilitate rearrangement of ARGs, including their translocation between chromosomes and plasmids. This review explores the molecular mechanisms underlying the HGT of ARGs, with a particular focus on clinically isolated antibiotic-resistant Gram-negative bacteria.</p>\u0000 </div>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":"69 7","pages":"367-376"},"PeriodicalIF":1.9,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144079067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Deep-Tissue In Vivo Imaging Using Bioluminescence in a Mouse Infection Model and the Path to High Sensitivity With Near-Infrared Luminescence","authors":"Daiki Yamaguchi, Keita Oki, Yuki Kaya, Yoshiaki Sakairi, Yuji Morita, Go Kamoshida","doi":"10.1111/1348-0421.13225","DOIUrl":"10.1111/1348-0421.13225","url":null,"abstract":"<div>\u0000 \u0000 <p>The analysis of bacterial infections using animal models has primarily relied on the average evaluation of many individuals at specific time points. Consequently, tracking temporal changes in an infection within the same individual is challenging. InVivo imaging techniques enable the longitudinal assessment of infection in the same individual while reducing the number of animals required. Understanding the dynamics of bacterial infections over time is crucial for elucidating disease mechanisms and developing effective treatment strategies. In this review, we summarize the In Vivo imaging techniques used to detect bacterial colonization in deep tissues in animal models of bacterial infection, along with efforts to enhance their sensitivity. In particular, we introduce a recently developed In Vivo imaging system that employs near-infrared luminescence to achieve high sensitivity and versatility. Furthermore, we discuss strategies for further improving its sensitivity.</p>\u0000 </div>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":"69 7","pages":"377-383"},"PeriodicalIF":1.9,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143990382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Issue Information – Cover","authors":"","doi":"10.1111/1348-0421.13139","DOIUrl":"https://doi.org/10.1111/1348-0421.13139","url":null,"abstract":"<p><b>Cover photograph</b>: Functions of soluble and membrane-bound C-type lectins against pathogens. A) Soluble C-type lectins are multimerized and inactivate pathogens by agglutinating or coating their surfaces. They also activate complement to kill pathogens and promote phagocytosis by opsonization. B) Membrane-bound C-type lectins are called C-type lectin receptors (CLRs). CLRs take up pathogens via endocytosis and degrade and inactivate them in lysosomes. The degraded antigens are presented on MHC-II, inducing an acquired immune response. C) CLRs associated with ITAM adapter molecules such as FcRg and DAP12 induce various inflammatory responses necessary for host defense. D) CLRs with hemITAM in the cytoplasmic region directly transmit activation signals. E) CLRs with the inhibitory motif ITIM suppress host immune responses. This can either suppress excessive inflammation caused by pathogens or allow pathogens to evade host immunity. F) ITAM has two sides. Many pathogen ligands are multivalent and transmit activation signals through ITAM, but monovalent ligands transmit inhibitory signals. G) Some CLRs capture pathogens on the cell surface and pass them to other pathogen recognition receptors. <i>Microbiol Immunol: 69:257-269</i>. Article link here\u0000 \u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":"69 5","pages":"i-ii"},"PeriodicalIF":1.9,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1348-0421.13139","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143905076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Coculture of Bifidobacterium bifidum G9-1 With Butyrate-Producing Bacteria Promotes Butyrate Production","authors":"Haruka Yokota, Yoshiki Tanaka, Hiroshi Ohno","doi":"10.1111/1348-0421.13224","DOIUrl":"10.1111/1348-0421.13224","url":null,"abstract":"<p>Supplementation with <i>Bifidobacterium bifidum</i> G9-1 (BBG9-1) has been established to enhance the production of butyrate, a short-chain fatty acid (SCFA) known for its beneficial effects in alleviating constipation. We hypothesized that BBG9-1 alters gut microbiota such that bacteria that produce butyric acid from lactate and acetate become more abundant. In this study, we sought to determine whether BBG9-1 promotes the growth of butyrate-producing bacteria and thereby enhances butyrate production. BBG9-1 was cocultured with different butyrate-producing bacteria to compare differences in the SCFA production of cocultures and monocultures. We indeed detected significant increases in the production of SCFAs in cocultures compared to monocultures. Moreover, lactate and butyrate production increased in a time-dependent manner in the BBG9-1 and <i>Faecalibacterium prausnitzii</i> ID 6052 coculture. In addition, acetate production in cocultures initially increased until 16 h, followed by a decline between 20 and 24 h, and a subsequent significant increase at 48 h. Comparatively, lactate and acetate production in the BBG9-1 and <i>Anaerostipes caccae</i> JCM 13470<sup>T</sup> coculture peaked at 16 h and declined thereafter, and butyrate production increased in a time-dependent manner. In contrast, lactate, acetate, and butyrate production in the BBG9-1 and <i>Roseburia hominis</i> JCM 17582<sup>T</sup> coculture increased in a time-dependent manner. These findings indicate that butyrate-producing bacteria increase butyrate production by utilizing BBG9-1-produced lactate and acetate. Thus, the butyrate-mediated physiological activity of BBG9-1 could be attributed to an indirect enhancement of butyrate production.</p>","PeriodicalId":18679,"journal":{"name":"Microbiology and Immunology","volume":"69 7","pages":"389-396"},"PeriodicalIF":1.9,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1348-0421.13224","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144018650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}