Bilophila wadsworthia is a commensal gram-negative anaerobic bacterium in the human gut that is often isolated from patients diagnosed with appendicitis and inflammatory bowel disease. Although previous studies have indicated that B. wadsworthia can cause and/or exacerbate inflammatory diseases, the precise underlying mechanism remains unclear. In the present study, we explored the inflammation-causing virulence factors of B. wadsworthia.
Methods
To identify the virulence factors of B. wadsworthia, we investigated the whole-genome sequences of 25 B. wadsworthia isolates. We then used the publicly available virulence factor database (VFDB) to search for virulence factor genes. We also conducted in vitro and in vivo studies to determine the importance of the selected virulence factors causing inflammation.
Results
Bilophila wadsworthia isolates have 30 common virulence factor genes that contribute to inflammation, invasion of the human body, and effector delivery system. These genes were associated with lipopolysaccharide, capsules, and membrane-associated proteins. Among them, lipoproteins, sometimes act as components of transporter proteins in the bacterial cell wall, upregulated the expression of tumor necrosis factor in murine spleen cells. However, the effect of lipoproteins was attenuated by a Toll-like receptor 2 antagonist. Additionally, orally administered B. wadsworthia and B. wadsworthia-produced lipoproteins worsened colitis in vivo.
Conclusions
Bilophila wadsworthia contains genes that encode various virulence factors. Among these, lipoproteins produced by B. wadsworthia can act as inflammation-inducing factors via Toll-like receptor 2.
{"title":"Lipoproteins from Bilophila wadsworthia cell wall induce innate immune responses through Toll-like receptor 2","authors":"Chika Yoshida , Mao Hagihara , Reina Azuma , Kenta Iwasaki , Akiko Nakamura , Hiroyuki Suematsu , Kaori Tanaka , Tadashi Ariyoshi , Kentaro Oka , Motomichi Takahashi , Yuka Yamagishi , Hiroshige Mikamo","doi":"10.1016/j.anaerobe.2025.103001","DOIUrl":"10.1016/j.anaerobe.2025.103001","url":null,"abstract":"<div><h3>Objectives</h3><div><em>Bilophila wadsworthia</em> is a commensal gram-negative anaerobic bacterium in the human gut that is often isolated from patients diagnosed with appendicitis and inflammatory bowel disease. Although previous studies have indicated that <em>B. wadsworthia</em> can cause and/or exacerbate inflammatory diseases, the precise underlying mechanism remains unclear. In the present study, we explored the inflammation-causing virulence factors of <em>B. wadsworthia</em>.</div></div><div><h3>Methods</h3><div>To identify the virulence factors of <em>B. wadsworthia</em>, we investigated the whole-genome sequences of 25 <em>B. wadsworthia</em> isolates. We then used the publicly available virulence factor database (VFDB) to search for virulence factor genes. We also conducted in vitro and in vivo studies to determine the importance of the selected virulence factors causing inflammation.</div></div><div><h3>Results</h3><div><em>Bilophila wadsworthia</em> isolates have 30 common virulence factor genes that contribute to inflammation, invasion of the human body, and effector delivery system. These genes were associated with lipopolysaccharide, capsules, and membrane-associated proteins. Among them, lipoproteins, sometimes act as components of transporter proteins in the bacterial cell wall, upregulated the expression of tumor necrosis factor in murine spleen cells. However, the effect of lipoproteins was attenuated by a Toll-like receptor 2 antagonist. Additionally, orally administered <em>B. wadsworthia</em> and <em>B. wadsworthia</em>-produced lipoproteins worsened colitis <em>in vivo</em>.</div></div><div><h3>Conclusions</h3><div><em>Bilophila wadsworthia</em> contains genes that encode various virulence factors. Among these, lipoproteins produced by <em>B. wadsworthia</em> can act as inflammation-inducing factors via Toll-like receptor 2.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"96 ","pages":"Article 103001"},"PeriodicalIF":2.6,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145190742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-24DOI: 10.1016/j.anaerobe.2025.103000
Deirdre A. Collins , Su Chen Lim , Jessica Chisholm , Molly Lattin , Linda Selvey , Simon Reid , Thomas V. Riley
Objectives
Community-onset Clostridioides (Clostridium) difficile infection (CDI) has risen to >80 % of all CDI cases in Australia. High prevalence of C. difficile contamination has been reported in many community sources including retail root vegetables. Household surfaces may become contaminated with C. difficile when storing and handling contaminated vegetables. This study aimed to determine the prevalence and molecular types of C. difficile present on retail root vegetables and household surfaces.
Methods
From April 2023 to March 2024, retail potatoes (n = 255) and onions (n = 305) were sampled at 3-monthly intervals. Environmental samples were collected from homes of householders in Queensland (n = 105) and Western Australia (n = 124) who regularly purchased unwashed potatoes. Swabs were collected from their countertop/chopping board, vegetable storage area and an unwashed potato. Pooled potato peels, pooled onion roots and household swab samples underwent enrichment culture for C. difficile. C. difficile isolates were characterized by PCR ribotyping and detection of toxin genes.
Results
C. difficile was cultured from 5.6 % of all 679 household samples, 35.3 % of 255 retail potato samples and 20.3 % of retail onion 305 samples. At least one environmental/potato sample was positive for 15.7 % of all 229 households. Among 84 C. difficile ribotypes (RTs), 056, 286, 101 and 125 predominated on vegetables in Western Australia and RTs 101, QX 098, 014/020 and QX 601 were most common on Queensland vegetables.
Conclusions
Toxigenic strains of C. difficile were identified on retail vegetables and within households, highlighting potential for CDI to be acquired within households. Populations at high risk of CDI e.g. patients with inflammatory bowel disease or cancer, could benefit from education on safe handling and cleaning of potential sources of C. difficile in their homes.
{"title":"Prevalence and molecular types of Clostridioides (Clostridium) difficile on Australian retail vegetables and household surfaces","authors":"Deirdre A. Collins , Su Chen Lim , Jessica Chisholm , Molly Lattin , Linda Selvey , Simon Reid , Thomas V. Riley","doi":"10.1016/j.anaerobe.2025.103000","DOIUrl":"10.1016/j.anaerobe.2025.103000","url":null,"abstract":"<div><h3>Objectives</h3><div>Community-onset <em>Clostridioides</em> (<em>Clostridium</em>) <em>difficile</em> infection (CDI) has risen to >80 % of all CDI cases in Australia. High prevalence of <em>C. difficile</em> contamination has been reported in many community sources including retail root vegetables. Household surfaces may become contaminated with <em>C. difficile</em> when storing and handling contaminated vegetables. This study aimed to determine the prevalence and molecular types of <em>C. difficile</em> present on retail root vegetables and household surfaces.</div></div><div><h3>Methods</h3><div>From April 2023 to March 2024, retail potatoes (n = 255) and onions (n = 305) were sampled at 3-monthly intervals. Environmental samples were collected from homes of householders in Queensland (n = 105) and Western Australia (n = 124) who regularly purchased unwashed potatoes. Swabs were collected from their countertop/chopping board, vegetable storage area and an unwashed potato. Pooled potato peels, pooled onion roots and household swab samples underwent enrichment culture for <em>C. difficile</em>. <em>C. difficile</em> isolates were characterized by PCR ribotyping and detection of toxin genes.</div></div><div><h3>Results</h3><div><em>C. difficile</em> was cultured from 5.6 % of all 679 household samples, 35.3 % of 255 retail potato samples and 20.3 % of retail onion 305 samples. At least one environmental/potato sample was positive for 15.7 % of all 229 households. Among 84 <em>C. difficile</em> ribotypes (RTs), 056, 286, 101 and 125 predominated on vegetables in Western Australia and RTs 101, QX 098, 014/020 and QX 601 were most common on Queensland vegetables.</div></div><div><h3>Conclusions</h3><div>Toxigenic strains of <em>C. difficile</em> were identified on retail vegetables and within households, highlighting potential for CDI to be acquired within households. Populations at high risk of CDI e.g. patients with inflammatory bowel disease or cancer, could benefit from education on safe handling and cleaning of potential sources of <em>C. difficile</em> in their homes.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"96 ","pages":"Article 103000"},"PeriodicalIF":2.6,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145172714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cosmetic products, which typically contain multiple ingredients such as ethanol, glycerol and Tween 80 (polysorbate 80), may influence the homeostasis of the skin microbiome. However, the effect of common ingredients on the anaerobic members of human skin microbiome is poorly studied. In this study, we directly evaluated the effects of common cosmetic ingredients on a dominant human skin anaerobe Cutibacterium acnes using in vitro techniques.
Materials and methods
Five cosmetic ingredients were added to seven C. acnes strains, including type strains of the three subspecies (types I, II, and III), and their effects were evaluated by monitoring growth curves based on turbidity measurements.
Results
All strains exhibited growth inhibition in response to high concentrations (10 % v/v) of ethanol and glycerol, whereas low concentrations (3 % and/or 1 % v/v) of ethanol enhanced bacterial growth. The nonionic detergent Tween 80 significantly enhanced the growth of type I strains, with some strains also producing insoluble precipitates, which may relate to comedogenesis. In contrast, type III strains did not produce precipitates. The two polyamines, putrescine and spermidine, elicited a biphasic response, with growth inhibition observed at higher concentrations and growth promotion at lower concentrations.
Conclusion
The response of C. acnes subspecies/strains to the cosmetic components varied with the different ingredient concentrations, often exhibiting opposite effects.
{"title":"Effects of common cosmetic ingredients on growth of dominant human skin inhabitant Cutibacterium acnes","authors":"Osamu Funatsu , Itaru Dekio , Hiroko Ishii , Reiko Shimatsu , Yutaka Shimokawa , Akihiko Asahina","doi":"10.1016/j.anaerobe.2025.102999","DOIUrl":"10.1016/j.anaerobe.2025.102999","url":null,"abstract":"<div><h3>Objectives</h3><div>Cosmetic products, which typically contain multiple ingredients such as ethanol, glycerol and Tween 80 (polysorbate 80), may influence the homeostasis of the skin microbiome. However, the effect of common ingredients on the anaerobic members of human skin microbiome is poorly studied. In this study, we directly evaluated the effects of common cosmetic ingredients on a dominant human skin anaerobe <em>Cutibacterium acnes</em> using <em>in vitro</em> techniques.</div></div><div><h3>Materials and methods</h3><div>Five cosmetic ingredients were added to seven <em>C</em>. <em>acnes</em> strains, including type strains of the three subspecies (types I, II, and III), and their effects were evaluated by monitoring growth curves based on turbidity measurements.</div></div><div><h3>Results</h3><div>All strains exhibited growth inhibition in response to high concentrations (10 % v/v) of ethanol and glycerol, whereas low concentrations (3 % and/or 1 % v/v) of ethanol enhanced bacterial growth. The nonionic detergent Tween 80 significantly enhanced the growth of type I strains, with some strains also producing insoluble precipitates, which may relate to comedogenesis. In contrast, type III strains did not produce precipitates. The two polyamines, putrescine and spermidine, elicited a biphasic response, with growth inhibition observed at higher concentrations and growth promotion at lower concentrations.</div></div><div><h3>Conclusion</h3><div>The response of <em>C. acnes</em> subspecies/strains to the cosmetic components varied with the different ingredient concentrations, often exhibiting opposite effects.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"96 ","pages":"Article 102999"},"PeriodicalIF":2.6,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145147570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-18DOI: 10.1016/j.anaerobe.2025.102998
Inga-Maria Frick, Ariane Neumann
Objectives
Gram-positive anaerobic cocci are opportunistic pathogens that exploit immune suppression or tissue injury to establish infections. Atopobium spp. are clinically relevant, being linked to bacterial vaginosis, abdominal wounds, pelvic abscesses, and dental infections. While clinical reports describe the involvement in detrimental host conditions, in-depth knowledge is missing to understand how these bacteria acquire essential nutrients to evade immune responses and directly interact with the human host.
Methods
Here we analyzed the growth of three blood-isolated Atopobium strains in different media and compared them to Finegoldia magna. Using radioactive binding studies, human serum albumin (HSA), a major component of serum, was identified as the primary binding partner, subsequently facilitating bacterial growth by providing essential nutrients. Next, we investigated the ability of Atopobium to interact with human blood-isolated neutrophils.
Results
Interestingly, Atopobium triggered neutrophil activation, detected by increased reactive oxygen species (ROS) production, secretion of the sepsis marker heparin-binding protein (HBP), and the induction of extracellular trap (NET) formation.
Conclusions
These findings provide new insights into how Atopobium utilizes host serum components and facilitates host interactions, highlighting their potential role in immune modulation and pathogenesis.
{"title":"Binding to thrive: Decoding Atopobium spp. interactions with host proteins and immune cells","authors":"Inga-Maria Frick, Ariane Neumann","doi":"10.1016/j.anaerobe.2025.102998","DOIUrl":"10.1016/j.anaerobe.2025.102998","url":null,"abstract":"<div><h3>Objectives</h3><div>Gram-positive anaerobic cocci are opportunistic pathogens that exploit immune suppression or tissue injury to establish infections. <em>Atopobium</em> spp. are clinically relevant, being linked to bacterial vaginosis, abdominal wounds, pelvic abscesses, and dental infections. While clinical reports describe the involvement in detrimental host conditions, in-depth knowledge is missing to understand how these bacteria acquire essential nutrients to evade immune responses and directly interact with the human host.</div></div><div><h3>Methods</h3><div>Here we analyzed the growth of three blood-isolated <em>Atopobium</em> strains in different media and compared them to <em>Finegoldia magna</em>. Using radioactive binding studies, human serum albumin (HSA), a major component of serum, was identified as the primary binding partner, subsequently facilitating bacterial growth by providing essential nutrients. Next, we investigated the ability of <em>Atopobium</em> to interact with human blood-isolated neutrophils.</div></div><div><h3>Results</h3><div>Interestingly, <em>Atopobium</em> triggered neutrophil activation, detected by increased reactive oxygen species (ROS) production, secretion of the sepsis marker heparin-binding protein (HBP), and the induction of extracellular trap (NET) formation.</div></div><div><h3>Conclusions</h3><div>These findings provide new insights into how <em>Atopobium</em> utilizes host serum components and facilitates host interactions, highlighting their potential role in immune modulation and pathogenesis.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"96 ","pages":"Article 102998"},"PeriodicalIF":2.6,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145090897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-18DOI: 10.1016/j.anaerobe.2025.102997
Charlie Zins , Loic Biere , Mohamed Braham , Rachel Chenouard , Matthieu Eveillard , Marie Kempf , Vincent Dubée , Hélène Pailhoriès
Finegoldia magna endocarditis is a rare and underdiagnosed condition, primarily affecting prosthetic valves. We report a case, along with a comprehensive literature review, highlighting its subacute presentation and the challenges in diagnosis due to frequent negative blood cultures. Molecular detection methods and prolonged delay for anaerobic cultures are crucial for identifying F. magna. Given the high risk of significant valvular damage, including abscess formation, surgical intervention might be required. Antibiotic treatments in the literature include penicillins, with or without metronidazole. Clinicians should consider this underestimated pathogen as a potential cause of early prosthetic valve endocarditis, particularly in cases of sterile blood cultures.
{"title":"Finegoldia magna, a neglected cause of endocarditis – case report","authors":"Charlie Zins , Loic Biere , Mohamed Braham , Rachel Chenouard , Matthieu Eveillard , Marie Kempf , Vincent Dubée , Hélène Pailhoriès","doi":"10.1016/j.anaerobe.2025.102997","DOIUrl":"10.1016/j.anaerobe.2025.102997","url":null,"abstract":"<div><div><em>Finegoldia magna</em> endocarditis is a rare and underdiagnosed condition, primarily affecting prosthetic valves. We report a case, along with a comprehensive literature review, highlighting its subacute presentation and the challenges in diagnosis due to frequent negative blood cultures. Molecular detection methods and prolonged delay for anaerobic cultures are crucial for identifying <em>F. magna</em>. Given the high risk of significant valvular damage, including abscess formation, surgical intervention might be required. Antibiotic treatments in the literature include penicillins, with or without metronidazole. Clinicians should consider this underestimated pathogen as a potential cause of early prosthetic valve endocarditis, particularly in cases of sterile blood cultures.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"96 ","pages":"Article 102997"},"PeriodicalIF":2.6,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-12DOI: 10.1016/j.anaerobe.2025.102996
Camila Fonseca Rizek , Marina Farrel Côrtes , Bianca Helena Ventura Fernandes , Silvia Figueiredo Costa , Evelyne Santana Girão , Roberta Cristina Martins , Sânia Alves dos Santos , Bruno de Melo Tavares , Luciani Silveira de Carvalho , Cecilia Leite Costa , Daniely Viana Costa , Geovania Maciel , Gerly Anne de Castro Brito , Lauro Vieira Perdigão Neto
Objectives
Clostridioides difficile is a major cause of nosocomial diarrhea, and its virulence is typically attributed to the production of toxins. However, other genomic factors may contribute to its pathogenicity. To study the in vivo aspects of C. difficile infection, various animal models have been employed. Zebrafish (Danio rerio) offers several advantages over mammalian models, but there are still few studies using it to evaluate C. difficile infection. Here, we aimed to explore in vivo virulence differences among clinical strains by employing the zebrafish embryo model using eight sequenced C. difficile isolates with distinct genomic profiles.
Methods
Embryos were microinjected with bacterial suspensions, and mortality and cardiac edema were monitored over 96 h. Survival and cardiotoxicity were assessed and correlated with whole-genome data and clinical outcomes.
Results
Two strains exhibited distinct pathogenic effects: HC48 (ST42) caused significantly increased mortality (p < 0.0001), and HC132 (ST669) induced cardiotoxicity in 20 % of embryos. Surprisingly, the hypervirulent control strain NAP1/027 did not produce enhanced virulence in this model.
Conclusion
While zebrafish embryos showed promise for distinguishing strain-specific virulence, limitations such as colonization capacity and host–microbe interactions suggest that further research is needed to validate this model for C. difficile virulence testing.
{"title":"Zebrafish as an in vivo model to study the pathogenicity of Clostridioides difficile clinical strains","authors":"Camila Fonseca Rizek , Marina Farrel Côrtes , Bianca Helena Ventura Fernandes , Silvia Figueiredo Costa , Evelyne Santana Girão , Roberta Cristina Martins , Sânia Alves dos Santos , Bruno de Melo Tavares , Luciani Silveira de Carvalho , Cecilia Leite Costa , Daniely Viana Costa , Geovania Maciel , Gerly Anne de Castro Brito , Lauro Vieira Perdigão Neto","doi":"10.1016/j.anaerobe.2025.102996","DOIUrl":"10.1016/j.anaerobe.2025.102996","url":null,"abstract":"<div><h3>Objectives</h3><div><em>Clostridioides difficile</em> is a major cause of nosocomial diarrhea, and its virulence is typically attributed to the production of toxins. However, other genomic factors may contribute to its pathogenicity. To study the <em>in vivo</em> aspects of <em>C. difficile</em> infection, various animal models have been employed. Zebrafish (<em>Danio rerio</em>) offers several advantages over mammalian models, but there are still few studies using it to evaluate <em>C. difficile</em> infection. Here, we aimed to explore <em>in vivo</em> virulence differences among clinical strains by employing the zebrafish embryo model using eight sequenced <em>C. difficile</em> isolates with distinct genomic profiles.</div></div><div><h3>Methods</h3><div>Embryos were microinjected with bacterial suspensions, and mortality and cardiac edema were monitored over 96 h. Survival and cardiotoxicity were assessed and correlated with whole-genome data and clinical outcomes.</div></div><div><h3>Results</h3><div>Two strains exhibited distinct pathogenic effects: HC48 (ST42) caused significantly increased mortality (p < 0.0001), and HC132 (ST669) induced cardiotoxicity in 20 % of embryos. Surprisingly, the hypervirulent control strain NAP1/027 did not produce enhanced virulence in this model.</div></div><div><h3>Conclusion</h3><div>While zebrafish embryos showed promise for distinguishing strain-specific virulence, limitations such as colonization capacity and host–microbe interactions suggest that further research is needed to validate this model for <em>C. difficile</em> virulence testing.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"96 ","pages":"Article 102996"},"PeriodicalIF":2.6,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145063283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Odoribacter splanchnicus is an anaerobe that normally inhabits the human intestine and rarely causes infections in humans. In recent years, however, three cases of O. splanchnicus bacteremia have been reported. We retrospectively searched our laboratory information system and detected five cases of O. splanchnicus bacteremia in 2014–2024. All cases of O. splanchnicus bacteremia reported to date have been associated with intestinal infection, but our five cases included one associated with decubitus ulcer infection. Antimicrobial susceptibility testing results were available in four of our five cases. O. splanchnicus showed susceptibility to beta-lactams and metronidazole. However, one isolate was resistant to clindamycin, and another showed intermediate susceptibility to levofloxacin. Among our five cases and the three previously reported cases, no patient was using immunosuppressive agents or had immunocompromising diseases except for one case with malignancy. While O. splanchnicus bacteremia is certainly rare, more cases may be found by searching the laboratory information system as in this investigation. Further accumulation of cases will help to elucidate the pathogenesis of infections caused by O. splanchnicus, which is endemic in the gastrointestinal tract, and will reveal more information on antimicrobial susceptibility.
{"title":"Odoribacter splanchnicus bacteremia: a rare condition associated with intestinal disease","authors":"Hiroshi Umemura , Hirokazu Kobayashi , Yumiko Tanimichi , Hiroyuki Nishiyama , Natsumi Ikumi , Masaki Nakajima , Sachio Tsuchida , Tomohiro Nakayama","doi":"10.1016/j.anaerobe.2025.102994","DOIUrl":"10.1016/j.anaerobe.2025.102994","url":null,"abstract":"<div><div><em>Odoribacter splanchnicus</em> is an anaerobe that normally inhabits the human intestine and rarely causes infections in humans. In recent years, however, three cases of <em>O. splanchnicus</em> bacteremia have been reported. We retrospectively searched our laboratory information system and detected five cases of <em>O. splanchnicus</em> bacteremia in 2014–2024. All cases of <em>O. splanchnicus</em> bacteremia reported to date have been associated with intestinal infection, but our five cases included one associated with decubitus ulcer infection. Antimicrobial susceptibility testing results were available in four of our five cases. <em>O. splanchnicus</em> showed susceptibility to beta-lactams and metronidazole. However, one isolate was resistant to clindamycin, and another showed intermediate susceptibility to levofloxacin. Among our five cases and the three previously reported cases, no patient was using immunosuppressive agents or had immunocompromising diseases except for one case with malignancy. While <em>O. splanchnicus</em> bacteremia is certainly rare, more cases may be found by searching the laboratory information system as in this investigation. Further accumulation of cases will help to elucidate the pathogenesis of infections caused by <em>O. splanchnicus</em>, which is endemic in the gastrointestinal tract, and will reveal more information on antimicrobial susceptibility.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"95 ","pages":"Article 102994"},"PeriodicalIF":2.6,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145008067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To identify risk factors for Clostridioides difficile infection (CDI) in patients with malignant tumours and establish a predictive model for clinical prevention and early intervention.
Methods
This retrospective study included 92 patients with malignant tumours (46 CDI-positive, 46 CDI-negative) admitted to our hospital. Demographic characteristics, clinical parameters, laboratory indicators and treatment factors were collected and analyzed. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors for CDI, and a predictive model was established and evaluated using receiver operating characteristic curve analysis.
Results
Patients with CDI had significantly lower serum albumin levels (30.12 ± 5.86 vs 34.15 ± 7.88 g/L, P = 0.007) and higher C-reactive protein (CRP) levels (89.38 ± 91.01 vs 49.17 ± 51.78 mg/L, P = 0.011) than patients without CDI. The CDI-positive group had significantly higher rates of multiple antibiotic use (52.2 % vs 10.9 %, P < 0.001) and corticosteroid/immunosuppressant use (58.7 % vs 30.4 %, P = 0.007) than the CDI-negative group. Multivariate logistic regression analysis identified four independent risk factors for CDI: multiple antibiotic use (odds ratio [OR] = 7.56, 95 % confidence interval [CI]: 2.41–23.73, P < 0.001), corticosteroid/immunosuppressant use (OR = 2.81, 95 % CI: 1.08–7.32, P = 0.035), serum albumin (per g/L increase: OR = 0.94, 95 % CI: 0.88–1.00, P = 0.049) and CRP (per mg/L increase: OR = 1.01, 95 % CI: 1.00–1.01, P = 0.047). The multivariate predictive model demonstrated excellent discriminative ability (area under the curve = 0.907).
Conclusion
Multiple antibiotic use, corticosteroid/immunosuppressant therapy, hypoalbuminaemia and elevated CRP are independent risk factors for CDI in patients with malignant tumours. The predictive model established in this study may help identify patients at high risk who could benefit from preventive interventions.
目的：探讨恶性肿瘤患者艰难梭菌感染（clostridiides difficile， CDI）的危险因素，建立临床预防和早期干预的预测模型。方法：回顾性分析我院收治的92例恶性肿瘤患者（46例cdi阳性，46例cdi阴性）。收集和分析患者的人口学特征、临床参数、实验室指标和治疗因素。采用单因素和多因素logistic回归分析，确定CDI的独立危险因素，建立预测模型并采用受试者工作特征曲线分析进行评价。结果：CDI患者血清白蛋白水平（30.12±5.86 vs 34.15±7.88 g/L, P = 0.007）明显低于无CDI患者，c反应蛋白（CRP）水平（89.38±91.01 vs 49.17±51.78 mg/L, P = 0.011）明显高于无CDI患者。cdi阳性组多种抗生素使用率（52.2% vs 10.9%, P < 0.001）和皮质类固醇/免疫抑制剂使用率（58.7% vs 30.4%, P = 0.007）均显著高于cdi阴性组。多因素logistic回归分析确定了CDI的四个独立危险因素：多种抗生素使用（优势比[OR] = 7.56, 95%可信区间[CI]: 2.41 ~ 23.73, P < 0.001）、皮质类固醇/免疫抑制剂使用（OR = 2.81, 95% CI: 1.08 ~ 7.32, P = 0.035）、血清白蛋白（每g/L增加：OR = 0.94, 95% CI: 0.88 ~ 1.00, P = 0.049）和CRP（每mg/L增加：OR = 1.01, 95% CI: 1.00 ~ 1.01, P = 0.047）。多元预测模型具有良好的判别能力（曲线下面积= 0.907）。结论：多种抗生素使用、皮质类固醇/免疫抑制剂治疗、低白蛋白血症和CRP升高是恶性肿瘤患者CDI的独立危险因素。本研究建立的预测模型可能有助于识别高危患者，哪些患者可以从预防干预中获益。
{"title":"Detection and risk factor analysis of Clostridioides difficile infection in patients with malignant tumours","authors":"Limin Guo , Zhen Zhang , Xianqin Cao , Weihua Guo , Aimin Yue , Yuhou Shen","doi":"10.1016/j.anaerobe.2025.102993","DOIUrl":"10.1016/j.anaerobe.2025.102993","url":null,"abstract":"<div><h3>Objective</h3><div>To identify risk factors for <em>Clostridioides difficile</em> infection (CDI) in patients with malignant tumours and establish a predictive model for clinical prevention and early intervention.</div></div><div><h3>Methods</h3><div>This retrospective study included 92 patients with malignant tumours (46 CDI-positive, 46 CDI-negative) admitted to our hospital. Demographic characteristics, clinical parameters, laboratory indicators and treatment factors were collected and analyzed. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors for CDI, and a predictive model was established and evaluated using receiver operating characteristic curve analysis.</div></div><div><h3>Results</h3><div>Patients with CDI had significantly lower serum albumin levels (30.12 ± 5.86 vs 34.15 ± 7.88 g/L, P = 0.007) and higher C-reactive protein (CRP) levels (89.38 ± 91.01 vs 49.17 ± 51.78 mg/L, P = 0.011) than patients without CDI. The CDI-positive group had significantly higher rates of multiple antibiotic use (52.2 % vs 10.9 %, P < 0.001) and corticosteroid/immunosuppressant use (58.7 % vs 30.4 %, P = 0.007) than the CDI-negative group. Multivariate logistic regression analysis identified four independent risk factors for CDI: multiple antibiotic use (odds ratio [OR] = 7.56, 95 % confidence interval [CI]: 2.41–23.73, P < 0.001), corticosteroid/immunosuppressant use (OR = 2.81, 95 % CI: 1.08–7.32, P = 0.035), serum albumin (per g/L increase: OR = 0.94, 95 % CI: 0.88–1.00, P = 0.049) and CRP (per mg/L increase: OR = 1.01, 95 % CI: 1.00–1.01, P = 0.047). The multivariate predictive model demonstrated excellent discriminative ability (area under the curve = 0.907).</div></div><div><h3>Conclusion</h3><div>Multiple antibiotic use, corticosteroid/immunosuppressant therapy, hypoalbuminaemia and elevated CRP are independent risk factors for CDI in patients with malignant tumours. The predictive model established in this study may help identify patients at high risk who could benefit from preventive interventions.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"96 ","pages":"Article 102993"},"PeriodicalIF":2.6,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Clostridioides difficile infection (CDI) is a well-known healthcare-associated diarrheal disease. Fidaxomicin, a key antibiotic used to treat CDI, targets bacterial RNA polymerase. However, some clinical isolates have mutations in rpoB, which reduces their susceptibility to this antibiotic. In this study, the effects of rpoB mutations on the virulence of C. difficile and efficacy of fidaxomicin against CDI were evaluated in vivo.
Methods
An rpoB mutant strain (C. difficile G1073R-2024) with reduced fidaxomicin susceptibility was generated through spontaneous induction in a murine CDI model from the parental strain C. difficile VPI 10463. The virulence and therapeutic responses of the mutant strain were compared with those of the parental strain using a CDI model, including survival rate, body weight changes, clinical scores, and bacterial loads in feces.
Results
C. difficile G1073R-2024 had an amino acid alteration in Gln1073Arg and the minimum inhibitory concentration of fidaxomicin was 128 μg/mL. In vivo virulence was not significantly different between strains. Fidaxomicin treatment resulted in 100 % survival rates and a comparable reduction in the bacterial load for both strains.
Conclusions
Fidaxomicin was effective against CDI caused by the rpoB mutant strain. The emergence of such mutations highlights the need for ongoing surveillance of drug resistance trends in clinical settings.
{"title":"In vivo efficacy of fidaxomicin against rpoB mutant Clostridioides difficile infection","authors":"Mai Thu Hoai , Yutaro Hitomi , Tsutomu Fujii , Yoshitomo Morinaga","doi":"10.1016/j.anaerobe.2025.102992","DOIUrl":"10.1016/j.anaerobe.2025.102992","url":null,"abstract":"<div><h3>Objectives</h3><div><em>Clostridioides difficile</em> infection (CDI) is a well-known healthcare-associated diarrheal disease. Fidaxomicin, a key antibiotic used to treat CDI, targets bacterial RNA polymerase. However, some clinical isolates have mutations in <em>rpoB</em>, which reduces their susceptibility to this antibiotic. In this study, the effects of <em>rpoB</em> mutations on the virulence of <em>C. difficile</em> and efficacy of fidaxomicin against CDI were evaluated <em>in vivo</em>.</div></div><div><h3>Methods</h3><div>An <em>rpoB</em> mutant strain (<em>C. difficile</em> G1073R-2024) with reduced fidaxomicin susceptibility was generated through spontaneous induction in a murine CDI model from the parental strain <em>C. difficile</em> VPI 10463. The virulence and therapeutic responses of the mutant strain were compared with those of the parental strain using a CDI model, including survival rate, body weight changes, clinical scores, and bacterial loads in feces.</div></div><div><h3>Results</h3><div><em>C. difficile</em> G1073R-2024 had an amino acid alteration in Gln1073Arg and the minimum inhibitory concentration of fidaxomicin was 128 μg/mL. <em>In vivo</em> virulence was not significantly different between strains. Fidaxomicin treatment resulted in 100 % survival rates and a comparable reduction in the bacterial load for both strains.</div></div><div><h3>Conclusions</h3><div>Fidaxomicin was effective against CDI caused by the <em>rpoB</em> mutant strain. The emergence of such mutations highlights the need for ongoing surveillance of drug resistance trends in clinical settings.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"95 ","pages":"Article 102992"},"PeriodicalIF":2.6,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-22DOI: 10.1016/j.anaerobe.2025.102991
Victoria Horrocks , Charlotte K. Hind , J. Mark Sutton , Rachel M. Tribe , A. James Mason
Objectives
This study evaluates how well a vaginal defined medium (VDM) replicates the in vivo metabolic behaviour of key vaginal microbiota members - Lactobacillus crispatus, L. jensenii, and diverse Gardnerella vaginalis isolates - compared to brain heart infusion (BHI) medium.
Methods
We used 1H NMR spectroscopy to characterise metabolic profiles during in vitro growth of Lactobacillus and Gardnerella species in VDM and BHI. Differences in metabolite production, growth, acidification, and carbohydrate utilisation were assessed.
Results
Both L.crispatus and L. jensenii grow well in VDM, produce substantially more lactate than in BHI, and acidify the culture more strongly - better reflecting the low pH environment of Lactobacillus-dominant vaginal microbiota. In contrast, G. vaginalis grows less robustly in VDM than in BHI, though key metabolic traits such as the Bifidobacterium shunt and mixed acid fermentation (evidenced by formate production) are preserved. Notably, neither genus consume available glucose, yet still ferment carbohydrates, suggesting a metabolic preference for glycogen over glucose. Evidence of glucose release further indicates glycogen breakdown in culture.
Conclusions
VDM more accurately models the metabolic activity and environmental effects of vaginal Lactobacillus species than BHI, particularly in terms of acidification and lactate production. Although G. vaginalis growth is limited in VDM, its characteristic metabolic pathways remain evident. These findings underscore the value of VDM in modelling key metabolic features of the vaginal microbiota, especially under conditions where Lactobacillus dominate or Gardnerella is prevalent.
{"title":"Metabolism of Lactobacillus and Gardnerella vaginalis in vaginal defined media","authors":"Victoria Horrocks , Charlotte K. Hind , J. Mark Sutton , Rachel M. Tribe , A. James Mason","doi":"10.1016/j.anaerobe.2025.102991","DOIUrl":"10.1016/j.anaerobe.2025.102991","url":null,"abstract":"<div><h3>Objectives</h3><div>This study evaluates how well a vaginal defined medium (VDM) replicates the i<em>n vivo</em> metabolic behaviour of key vaginal microbiota members - <em>Lactobacillus crispatus</em>, <em>L. jensenii</em>, and diverse <em>Gardnerella vaginalis</em> isolates - compared to brain heart infusion (BHI) medium.</div></div><div><h3>Methods</h3><div>We used <sup>1</sup>H NMR spectroscopy to characterise metabolic profiles during <em>in vitro</em> growth of <em>Lactobacillus</em> and <em>Gardnerella</em> species in VDM and BHI. Differences in metabolite production, growth, acidification, and carbohydrate utilisation were assessed.</div></div><div><h3>Results</h3><div>Both <em>L.</em> <em>crispatus</em> and <em>L. jensenii</em> grow well in VDM, produce substantially more lactate than in BHI, and acidify the culture more strongly - better reflecting the low pH environment of <em>Lactobacillus</em>-dominant vaginal microbiota. In contrast, <em>G. vaginalis</em> grows less robustly in VDM than in BHI, though key metabolic traits such as the Bifidobacterium shunt and mixed acid fermentation (evidenced by formate production) are preserved. Notably, neither genus consume available glucose, yet still ferment carbohydrates, suggesting a metabolic preference for glycogen over glucose. Evidence of glucose release further indicates glycogen breakdown in culture.</div></div><div><h3>Conclusions</h3><div>VDM more accurately models the metabolic activity and environmental effects of vaginal <em>Lactobacillus</em> species than BHI, particularly in terms of acidification and lactate production. Although <em>G. vaginalis</em> growth is limited in VDM, its characteristic metabolic pathways remain evident. These findings underscore the value of VDM in modelling key metabolic features of the vaginal microbiota, especially under conditions where <em>Lactobacillus</em> dominate or <em>Gardnerella</em> is prevalent.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"95 ","pages":"Article 102991"},"PeriodicalIF":2.6,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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