Pub Date : 2025-06-07DOI: 10.1016/j.anaerobe.2025.102977
Marek Kwaśniewski , Tomasz M. Karpiński
This study analyzed retrospectively 291 semen samples, identifying diverse anaerobic bacteria, mainly Prevotella (49 % of all isolates), Veillonella, and Peptoniphilus. Most isolates were susceptible to amoxicillin/clavulanic acid, suggesting its therapeutic potential in male infertility. Resistance to metronidazole was observed in Peptoniphilus, Veillonella, and Propionimicrobium, while Bacteroides exhibited resistance to benzylpenicillin.
{"title":"Identification and characterization of anaerobic bacteria in human semen: A retrospective study","authors":"Marek Kwaśniewski , Tomasz M. Karpiński","doi":"10.1016/j.anaerobe.2025.102977","DOIUrl":"10.1016/j.anaerobe.2025.102977","url":null,"abstract":"<div><div>This study analyzed retrospectively 291 semen samples, identifying diverse anaerobic bacteria, mainly <em>Prevotella</em> (49 % of all isolates), <em>Veillonella</em>, and <em>Peptoniphilus</em>. Most isolates were susceptible to amoxicillin/clavulanic acid, suggesting its therapeutic potential in male infertility. Resistance to metronidazole was observed in <em>Peptoniphilus, Veillonella</em>, and <em>Propionimicrobium</em>, while <em>Bacteroides</em> exhibited resistance to benzylpenicillin.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"94 ","pages":"Article 102977"},"PeriodicalIF":2.5,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144257245","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 : 2025-06-06DOI: 10.1016/j.anaerobe.2025.102978
Anastasia Karatzia , Danai Aristeridou , Wawi Kantz , A. Carmine Colavecchia , Harish Madhava , Mohammad Ateya , Carole Czudek , Patrick H. Kelly , Kate Halsby
Objective
We evaluated machine learning (ML) model feasibility to predict Clostridioides difficile infection (CDI) six months prior to onset and to identify early predictors over a longer period.
Methods
A retrospective analysis was performed using electronic health records data from US adults (Optum Market Clarity). Cases with CDI and non-CDI controls were identified. A 1:1 coarsened exact matching algorithm was applied, with final analysis cohorts of 4736 cases and 4732 controls. CDI-relevant features were identified from the published literature, and information was extracted for >900 features. The final model was trained on 597 mostly binary features. Feature information during the 6 months prior to date of first CDI diagnosis was hidden to the model to identify patients at risk for CDI with a longer time horizon. Sensitivity analysis was conducted on cases aged 65–80 years.
Results
Median age was 65 years (19–88) in case and control cohorts. The Gradient Boosted Trees ML model had an Area Under the Curve Receiver Operating Characteristic (AUC-ROC) of 0.79. Post-model bias evaluation revealed disparities in sensitivity (race). Long-term predictors included hospitalization days. While some predictors were exclusive to the 65–80 years model, others were more strongly associated with CDI in the overall model.
Conclusions
We developed a ML model that can identify patient groups at increased risk for primary CDI. While the predictive capability of this ML model is promising, validation is needed before exploring its readiness for use in healthcare settings to inform preventive measures for CDI.
{"title":"AI4CDI: Introducing a novel machine learning approach to demonstrate feasibility of timely and early identification of at-risk populations for Clostridioides difficile infections","authors":"Anastasia Karatzia , Danai Aristeridou , Wawi Kantz , A. Carmine Colavecchia , Harish Madhava , Mohammad Ateya , Carole Czudek , Patrick H. Kelly , Kate Halsby","doi":"10.1016/j.anaerobe.2025.102978","DOIUrl":"10.1016/j.anaerobe.2025.102978","url":null,"abstract":"<div><h3>Objective</h3><div>We evaluated machine learning (ML) model feasibility to predict <em>Clostridioides difficile</em> infection (CDI) six months prior to onset and to identify early predictors over a longer period.</div></div><div><h3>Methods</h3><div>A retrospective analysis was performed using electronic health records data from US adults (Optum Market Clarity). Cases with CDI and non-CDI controls were identified. A 1:1 coarsened exact matching algorithm was applied, with final analysis cohorts of 4736 cases and 4732 controls. CDI-relevant features were identified from the published literature, and information was extracted for >900 features. The final model was trained on 597 mostly binary features. Feature information during the 6 months prior to date of first CDI diagnosis was hidden to the model to identify patients at risk for CDI with a longer time horizon. Sensitivity analysis was conducted on cases aged 65–80 years.</div></div><div><h3>Results</h3><div>Median age was 65 years (19–88) in case and control cohorts. The Gradient Boosted Trees ML model had an Area Under the Curve Receiver Operating Characteristic (AUC-ROC) of 0.79. Post-model bias evaluation revealed disparities in sensitivity (race). Long-term predictors included hospitalization days. While some predictors were exclusive to the 65–80 years model, others were more strongly associated with CDI in the overall model.</div></div><div><h3>Conclusions</h3><div>We developed a ML model that can identify patient groups at increased risk for primary CDI. While the predictive capability of this ML model is promising, validation is needed before exploring its readiness for use in healthcare settings to inform preventive measures for CDI.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"94 ","pages":"Article 102978"},"PeriodicalIF":2.5,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144246088","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}
The culture performance of Fastidious Anaerobe Agar (FAA-HB) was evaluated for fecal samples and candidate-species for EUCAST antimicrobial susceptibility testing (AST). Thirty-six anaerobic species were cultured from fecal samples and most EUCAST candidate-species exhibited confluent growth within 16–20 h. The FAA-HB performed excellent for both culture and AST of a broad spectrum of anaerobic bacteria.
{"title":"Culture performance of Fastidious Anaerobe Agar for frequently-encountered anaerobic bacteria, and potential application in EUCAST antimicrobial susceptibility testing","authors":"Katrine Agerbo Hovmand , Ziyap Acar , Emil Ainsworth Jochumsen , Sanne Malig , Jens Kjeldsen , Dorte Kinggaard Holm , Anna Christine Nilsson , Torkell Ellingsen , Maja Skov Kragsnaes , Ulrik Stenz Justesen","doi":"10.1016/j.anaerobe.2025.102972","DOIUrl":"10.1016/j.anaerobe.2025.102972","url":null,"abstract":"<div><div>The culture performance of Fastidious Anaerobe Agar (FAA-HB) was evaluated for fecal samples and candidate-species for EUCAST antimicrobial susceptibility testing (AST). Thirty-six anaerobic species were cultured from fecal samples and most EUCAST candidate-species exhibited confluent growth within 16–20 h. The FAA-HB performed excellent for both culture and AST of a broad spectrum of anaerobic bacteria.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"93 ","pages":"Article 102972"},"PeriodicalIF":2.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144118617","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}
Blackleg, also known as black quarter (BQ), is an acute and lethal infection in bovines and caused by the anaerobic bacterium- Clostridium chauvoei. A killed vaccine is available for disease control, and evaluating the immune response to the vaccine or natural infection in susceptible animals is crucial for implementing effective vaccination strategies in endemic regions. This study focused on the development and comparative evaluation of indirect ELISAs based on native antigens (whole cell and flagellar) from C. chauvoei to detect blackleg-specific antibodies in serum samples collected from cattle.
Methods
Whole cell and flagellar antigens were extracted conventionally from C. chauvoei strain NIVEDIBQ1, and optimized indirect ELISAs were compared with the indirect hemagglutination assay (IHA). These assays were used to screen 810 serum samples collected from Andhra Pradesh, India, where blackleg is endemic.
Results
Optimum antigen concentrations (250 ng of whole cell antigen and 300 ng of flagella), serum dilution (1:100), and conjugate dilution (1: 10,000) were determined using the checkerboard titration method. The optimized assays reliably detected C. chauvoei-specific antibodies at serum dilutions as low as 1:1600 for whole cell antigens, and 1: 800 for flagellar antigens without any cross-reactions. A comparison between IHA and indirect ELISAs using Cohen's Kappa analysis indicated that the two assays were equally effective. A diagnostic sensitivity (DSn) of 96.0 % and 95.0 %, and diagnostic specificity (DSp) of 95.0 % and 97.0 %, with cut-off criteria of >20.7632 and 18.579, for whole cell and flagellar antigens, respectively, was observed after ROC analysis. The observed seropositivity rates in Andhra Pradesh were 57 % (462) and 40.9 % (332) for whole cell and flagellar antigen based indirect ELISAs, respectively.
Conclusion
This study demonstrated the potential application of native antigen-based indirect ELISAs for monitoring blackleg-specific antibodies in cattle from endemic regions.
{"title":"Comparative evaluation of indirect-ELISAs based on native antigens of Clostridium chauvoei for the detection of blackleg-specific antibodies in cattle","authors":"Mevaliya Amitkumar , Awadhesh Prajapati , Suresh Bindu , Sripada Sairam , Anand Shirisha , Mandrira Ramakrishna Namrutha , Roopa Anandamurthy Hemanth , Revanaiah Yogisharadhya , Mohammed Mudassar Chanda , Sathish Bhadravati Shivachandra","doi":"10.1016/j.anaerobe.2025.102975","DOIUrl":"10.1016/j.anaerobe.2025.102975","url":null,"abstract":"<div><h3>Objective</h3><div>Blackleg, also known as black quarter (BQ), is an acute and lethal infection in bovines and caused by the anaerobic bacterium- <em>Clostridium chauvoei.</em> A killed vaccine is available for disease control, and evaluating the immune response to the vaccine or natural infection in susceptible animals is crucial for implementing effective vaccination strategies in endemic regions. This study focused on the development and comparative evaluation of indirect ELISAs based on native antigens (whole cell and flagellar) from <em>C</em>. <em>chauvoei</em> to detect blackleg-specific antibodies in serum samples collected from cattle.</div></div><div><h3>Methods</h3><div>Whole cell and flagellar antigens were extracted conventionally from <em>C</em>. <em>chauvoei</em> strain NIVEDIBQ1, and optimized indirect ELISAs were compared with the indirect hemagglutination assay (IHA). These assays were used to screen 810 serum samples collected from Andhra Pradesh, India, where blackleg is endemic.</div></div><div><h3>Results</h3><div>Optimum antigen concentrations (250 ng of whole cell antigen and 300 ng of flagella), serum dilution (1:100), and conjugate dilution (1: 10,000) were determined using the checkerboard titration method. The optimized assays reliably detected <em>C</em>. <em>chauvoei</em>-specific antibodies at serum dilutions as low as 1:1600 for whole cell antigens, and 1: 800 for flagellar antigens without any cross-reactions. A comparison between IHA and indirect ELISAs using Cohen's Kappa analysis indicated that the two assays were equally effective. A diagnostic sensitivity (DSn) of 96.0 % and 95.0 %, and diagnostic specificity (DSp) of 95.0 % and 97.0 %, with cut-off criteria of >20.7632 and 18.579, for whole cell and flagellar antigens, respectively, was observed after ROC analysis. The observed seropositivity rates in Andhra Pradesh were 57 % (462) and 40.9 % (332) for whole cell and flagellar antigen based indirect ELISAs, respectively.</div></div><div><h3>Conclusion</h3><div>This study demonstrated the potential application of native antigen-based indirect ELISAs for monitoring blackleg-specific antibodies in cattle from endemic regions.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"94 ","pages":"Article 102975"},"PeriodicalIF":2.5,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144198082","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 : 2025-05-30DOI: 10.1016/j.anaerobe.2025.102973
Katharine Xiwen Huang , Justin Deane Jackson
We present a rare case of Desulfovibrio desulfuricans bacteraemia and associated liver abscess. A 72-year-old Caucasian woman presented with an acute history of fevers, rigors and abdominal pain. She was managed empirically with ceftriaxone and metronidazole and required 24 hours of inotropic support due to hypotension from sepsis. A computed tomography scan of her abdomen demonstrated a 6cm liver abscess in maximal diameter. On day seven of her admission, blood cultures flagged an anaerobic gram-negative bacillus, which was later identified by MALDI-TOF MS as Desulfovibrio desulfuricans. The isolate was susceptible to amoxicillin-clavulanic acid, ertapenem, moxifloxacin, clindamycin and metronidazole but resistant to piperacillin-tazobactam. Despite percutaneous drainage on day two of admission, her fevers persisted for three weeks. On day nine of admission, intravenous ceftriaxone and metronidazole were switched to amoxicillin-clavulanic acid, which was administered for a total of six weeks, resulting in clinical resolution. Our case highlights Desulfovibrio desulfuricans as an uncommon cause of liver abscess and one which is important to consider if culturing an anaerobic, spiral gram-negative bacilli. Empirical antibiotics need to be carefully considered as there may be resistance to beta-lactam antibiotics including piperacillin-tazobactam.
{"title":"Desulfovibrio desulfuricans bacteraemia and associated liver abscess: Case report and literature review","authors":"Katharine Xiwen Huang , Justin Deane Jackson","doi":"10.1016/j.anaerobe.2025.102973","DOIUrl":"10.1016/j.anaerobe.2025.102973","url":null,"abstract":"<div><div>We present a rare case of <em>Desulfovibrio desulfuricans</em> bacteraemia and associated liver abscess. A 72-year-old Caucasian woman presented with an acute history of fevers, rigors and abdominal pain. She was managed empirically with ceftriaxone and metronidazole and required 24 hours of inotropic support due to hypotension from sepsis. A computed tomography scan of her abdomen demonstrated a 6cm liver abscess in maximal diameter. On day seven of her admission, blood cultures flagged an anaerobic gram-negative bacillus, which was later identified by MALDI-TOF MS as <em>Desulfovibrio desulfuricans</em>. The isolate was susceptible to amoxicillin-clavulanic acid, ertapenem, moxifloxacin, clindamycin and metronidazole but resistant to piperacillin-tazobactam. Despite percutaneous drainage on day two of admission, her fevers persisted for three weeks. On day nine of admission, intravenous ceftriaxone and metronidazole were switched to amoxicillin-clavulanic acid, which was administered for a total of six weeks, resulting in clinical resolution. Our case highlights <em>Desulfovibrio desulfuricans</em> as an uncommon cause of liver abscess and one which is important to consider if culturing an anaerobic, spiral gram-negative bacilli. Empirical antibiotics need to be carefully considered as there may be resistance to beta-lactam antibiotics including piperacillin-tazobactam.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"95 ","pages":"Article 102973"},"PeriodicalIF":2.6,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144198083","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 is a gram-positive, spore-forming anaerobic enteropathogen responsible for a wide spectrum of clinical diseases ranging from mild diarrhoea to pseudomembranous colitis or toxic megacolon. It is the main cause of healthcare-associated diarrhoea, but community-associated Clostridioides difficile infections (CDI) have been increasingly reported in the past few years. This narrative review aims to provide a comprehensive overview of the methods and most recommended strategy, and a brief description of the main pitfalls and new developments in CDI diagnosis. Underdiagnosis still remains important due to a lack of physicians' awareness for CDI. Appropriate selection of stool samples, and implementation of rejection criteria at the lab level are essential to provide an accurate diagnosis of CDI. Methods used for the diagnosis are usually classified into 3 groups according to their targets: those detecting the presence of C. difficile (culture, enzyme immunoassays [EIA] for glutamate dehydrogenase [GDH]), those detecting free toxins in stools (EIA for toxins) and those detecting a toxigenic C. difficile strain (nucleic acid amplification test [NAAT], toxigenic culture). No stand-alone method can be used for the CDI diagnosis. The European Society for Clinical Microbiology and Infectious Diseases (ESCMID) recommends a two-step algorithm with a sensitive screening test (NAAT or GDH EIA). If the screening test is negative, the CDI diagnosis can be ruled out. If the screening test is positive, a second highly specific test targeting free toxins should be used, such as EIA for toxin A/B. Implementing this strategy enables a better accuracy of CDI diagnosis, thus improving patient's management and clinical outcomes.
{"title":"Laboratory diagnosis of Clostridioides difficile infection: past, present and future","authors":"Frédéric Barbut , Imane Mostaghat , Muriel Ehmig , Yasmine Roukoz-Diab , Jeanne Couturier","doi":"10.1016/j.anaerobe.2025.102974","DOIUrl":"10.1016/j.anaerobe.2025.102974","url":null,"abstract":"<div><div><em>Clostridioides difficile</em> is a gram-positive, spore-forming anaerobic enteropathogen responsible for a wide spectrum of clinical diseases ranging from mild diarrhoea to pseudomembranous colitis or toxic megacolon. It is the main cause of healthcare-associated diarrhoea, but community-associated <em>Clostridioides difficile</em> infections (CDI) have been increasingly reported in the past few years. This narrative review aims to provide a comprehensive overview of the methods and most recommended strategy, and a brief description of the main pitfalls and new developments in CDI diagnosis. Underdiagnosis still remains important due to a lack of physicians' awareness for CDI. Appropriate selection of stool samples, and implementation of rejection criteria at the lab level are essential to provide an accurate diagnosis of CDI. Methods used for the diagnosis are usually classified into 3 groups according to their targets: those detecting the presence of <em>C. difficile</em> (culture, enzyme immunoassays [EIA] for glutamate dehydrogenase [GDH]), those detecting free toxins in stools (EIA for toxins) and those detecting a toxigenic <em>C. difficile</em> strain (nucleic acid amplification test [NAAT], toxigenic culture). No stand-alone method can be used for the CDI diagnosis. The European Society for Clinical Microbiology and Infectious Diseases (ESCMID) recommends a two-step algorithm with a sensitive screening test (NAAT or GDH EIA). If the screening test is negative, the CDI diagnosis can be ruled out. If the screening test is positive, a second highly specific test targeting free toxins should be used, such as EIA for toxin A/B. Implementing this strategy enables a better accuracy of CDI diagnosis, thus improving patient's management and clinical outcomes.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"93 ","pages":"Article 102974"},"PeriodicalIF":2.5,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140966","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 : 2025-05-09DOI: 10.1016/j.anaerobe.2025.102971
Daniela Wetzel , Arshad Rizvi , Adrianne N. Edwards , Shonna M. McBride
Objectives
Clostridioides difficile is a major gastrointestinal pathogen that is transmitted as a dormant spore. As an intestinal pathogen, C. difficile must contend with variable environmental conditions, including fluctuations in pH and nutrient availability. Nutrition and pH both influence growth and spore formation, but how pH and nutrition jointly influence sporulation are not known. In this study, we investigated the dual impact of pH and pH-dependent metabolism on C. difficile sporulation.
Methods
We examined the impacts of pH and the metabolite acetoin on C. difficile growth, gene expression, and sporulation.
Results
We found that expression of the predicted acetoin dehydrogenase operon, CD0035-CD0039, was pH-dependent and repressed by acetoin and pyruvate. Regulation of the C. difficile CD0035-CD0039 locus is distinct from characterized orthologous systems and appears to involve a co-transcribed DeoR-family regulator, rather than a sigma54-dependent activator. In addition, an CD0036 null mutant produced significantly more spores and initiated sporulation earlier than the parent strain. However, unlike other Firmicutes, growth and culture density of C. difficile was not increased by acetoin availability or disruption of the dehydrogenase pathway.
Conclusions
Together, these results indicate that acetoin, pH, and the CD0036-CD0039 dehydrogenase pathway play important roles in nutritional repression of sporulation in C. difficile. However, the data do not support the involvement of the CD0036-CD0039 pathway in acetoin metabolism and acetoin is not a significant stationary phase energy source for C. difficile.
{"title":"A metabolite dehydrogenase pathway represses sporulation of Clostridioides difficile","authors":"Daniela Wetzel , Arshad Rizvi , Adrianne N. Edwards , Shonna M. McBride","doi":"10.1016/j.anaerobe.2025.102971","DOIUrl":"10.1016/j.anaerobe.2025.102971","url":null,"abstract":"<div><h3>Objectives</h3><div><em>Clostridioides difficile</em> is a major gastrointestinal pathogen that is transmitted as a dormant spore. As an intestinal pathogen, <em>C. difficile</em> must contend with variable environmental conditions, including fluctuations in pH and nutrient availability. Nutrition and pH both influence growth and spore formation, but how pH and nutrition jointly influence sporulation are not known. In this study, we investigated the dual impact of pH and pH-dependent metabolism on <em>C. difficile</em> sporulation.</div></div><div><h3>Methods</h3><div>We examined the impacts of pH and the metabolite acetoin on <em>C. difficile</em> growth, gene expression, and sporulation.</div></div><div><h3>Results</h3><div>We found that expression of the predicted acetoin dehydrogenase operon, <em>CD0035-CD0039</em>, was pH-dependent and repressed by acetoin and pyruvate. Regulation of the <em>C. difficile CD0035-CD0039</em> locus is distinct from characterized orthologous systems and appears to involve a co-transcribed DeoR-family regulator, rather than a sigma<sup>54</sup>-dependent activator. In addition, an <em>CD0036</em> null mutant produced significantly more spores and initiated sporulation earlier than the parent strain. However, unlike other Firmicutes, growth and culture density of <em>C. difficile</em> was not increased by acetoin availability or disruption of the dehydrogenase pathway.</div></div><div><h3>Conclusions</h3><div>Together, these results indicate that acetoin, pH, and the <em>CD0036-CD0039</em> dehydrogenase pathway play important roles in nutritional repression of sporulation in <em>C. difficile</em>. However, the data do not support the involvement of the CD0036-CD0039 pathway in acetoin metabolism and acetoin is not a significant stationary phase energy source for <em>C. difficile</em>.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"93 ","pages":"Article 102971"},"PeriodicalIF":2.5,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143971075","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}
This study aims to evaluate the concordance between the disc diffusion test (DDT) and custom-designed Sensititre® Broth Microdilution plates and to estimate their respective sensitivity and specificity for antimicrobial susceptibility testing (AST) of Bacteroides fragilis group (BFG) clinical isolates.
Methods
AST was performed on 126 BFG isolates using both DDT and Sensititre® methods according to the 2024 CA-SFM guidelines. Cohen's kappa coefficients were used to assess concordance, while a Bayesian approach estimated sensitivity and specificity with 95 % confidence intervals (95 % CIs) for amoxicillin-clavulanate (AMC), piperacillin-tazobactam (PTZ), imipenem (IPM), clindamycin (CLI), metronidazole (MTR), and moxifloxacin (MXF).
Results
Cohen's kappa coefficients with 95 % CIs for AMC, PTZ, IPM, CLI, MTR, and MXF were 0.92 (0.85–1.00), 0.70 (0.56–0.83), 0.96 (0.92–1.00), 0.98 (0.94–1.00), 0.96 (0.89–1.00), and 0.70 (0.58–0.82), respectively. DDT demonstrated sensitivity > 0.8 for all antibiotics, and specificity > 0.8 except for PTZ (0.51; 0.37–0.65) and CLI (0.71; 0.58–0.82). Sensititre® exhibited sensitivity > 0.9 for all antibiotics except for PTZ (0.86; 0.70–0.99), and specificity > 0.9 except for MXF (0.88; 0.75–0.99).
Conclusions
DDT and Sensititre® Broth Microdilution demonstrated strong concordance for most antibiotics. Predictive values estimated using Bayesian model showed that Sensititre® offered the highest overall sensitivity and specificity.
{"title":"Comparison of disc diffusion and Sensititre® Broth Microdilution methods for antimicrobial susceptibility testing of Bacteroides fragilis group clinical isolates following the French guidelines","authors":"Gauthier Delvallez , Laure Diancourt , Julie Germond , Pascal Campagne , Bruno Dupuy","doi":"10.1016/j.anaerobe.2025.102969","DOIUrl":"10.1016/j.anaerobe.2025.102969","url":null,"abstract":"<div><h3>Objectives</h3><div>This study aims to evaluate the concordance between the disc diffusion test (DDT) and custom-designed Sensititre® Broth Microdilution plates and to estimate their respective sensitivity and specificity for antimicrobial susceptibility testing (AST) of <em>Bacteroides fragilis</em> group (BFG) clinical isolates.</div></div><div><h3>Methods</h3><div>AST was performed on 126 BFG isolates using both DDT and Sensititre® methods according to the 2024 CA-SFM guidelines. Cohen's kappa coefficients were used to assess concordance, while a Bayesian approach estimated sensitivity and specificity with 95 % confidence intervals (95 % CIs) for amoxicillin-clavulanate (AMC), piperacillin-tazobactam (PTZ), imipenem (IPM), clindamycin (CLI), metronidazole (MTR), and moxifloxacin (MXF).</div></div><div><h3>Results</h3><div>Cohen's kappa coefficients with 95 % CIs for AMC, PTZ, IPM, CLI, MTR, and MXF were 0.92 (0.85–1.00), 0.70 (0.56–0.83), 0.96 (0.92–1.00), 0.98 (0.94–1.00), 0.96 (0.89–1.00), and 0.70 (0.58–0.82), respectively. DDT demonstrated sensitivity > 0.8 for all antibiotics, and specificity > 0.8 except for PTZ (0.51; 0.37–0.65) and CLI (0.71; 0.58–0.82). Sensititre® exhibited sensitivity > 0.9 for all antibiotics except for PTZ (0.86; 0.70–0.99), and specificity > 0.9 except for MXF (0.88; 0.75–0.99).</div></div><div><h3>Conclusions</h3><div>DDT and Sensititre® Broth Microdilution demonstrated strong concordance for most antibiotics. Predictive values estimated using Bayesian model showed that Sensititre® offered the highest overall sensitivity and specificity<em>.</em></div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"93 ","pages":"Article 102969"},"PeriodicalIF":2.5,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143961927","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 explore a comprehensive genomic analysis of Clostridium perfringens type A strains from diverse regions in China, investigating their virulence genes, antibiotic resistance genes, and mobile genetic elements (MGEs) to inform strategies for infection control and resistance gene surveillance.
Methods
We conducted whole-genome sequencing on 168 C. perfringens type A strains from nine provinces in China (2016–2021). Previously described alpha-toxin (PLC) sequence typing for C. perfringens was used for comparisons with core genome multilocus sequence typing. Virulence genes, antibiotic resistance genes, and MGEs, including CRISPR/Cas, prophages, and plasmids of C. perfringens type A were investigated by molecular and bioinformatic methods.
Results
PLC type II contained the largest number of isolates (n = 44). The same type strains were largely clustered in the same branches. Tetracycline resistance genes tetA(P) and tetB(P) had high prevalence in type A isolates. 395 prophages were predicted including 265 “incomplete,” 55 “questionable,” and 75 “intact” prophages. CRISPR/Cas systems were more common in isolates from humans (63 %) than in those from animals and food (52 % and 46 %, respectively). Fifty-seven percent of strains likely had the tcp conjugation locus (tcpC to tcpH), and 12 isolates likely carried the conjugative pCW3 plasmid. Type A strains exhibited fewer plasmid-encoded toxins.
Conclusions
cgMLST analysis demonstrated some micro-evolution and regional transmission trends within type A, which exhibited partial correlated with PLC typing. This study highlights the need for enhanced surveillance of antimicrobial resistance and pathogenicity-associated MGEs in C. perfringens type A.
{"title":"Genomic analysis and mobile genetic elements carriage of Clostridium perfringens type A","authors":"Yajun Jiang , Haoran Zheng , Lulu Bai, Yuanyuan Wang, Jiaxin Zhong, Wenzhu Zhang, Telong Xu, Yuanhang Pan, Jingjing Tang, Jinxing Lu, Bike Zhang, Yuan Wu","doi":"10.1016/j.anaerobe.2025.102970","DOIUrl":"10.1016/j.anaerobe.2025.102970","url":null,"abstract":"<div><h3>Objectives</h3><div>To explore a comprehensive genomic analysis of <em>Clostridium perfringens</em> type A strains from diverse regions in China, investigating their virulence genes, antibiotic resistance genes, and mobile genetic elements (MGEs) to inform strategies for infection control and resistance gene surveillance.</div></div><div><h3>Methods</h3><div>We conducted whole-genome sequencing on 168 <em>C. perfringens</em> type A strains from nine provinces in China (2016–2021). Previously described alpha-toxin (PLC) sequence typing for <em>C. perfringens</em> was used for comparisons with core genome multilocus sequence typing. Virulence genes, antibiotic resistance genes, and MGEs, including CRISPR/Cas, prophages, and plasmids of <em>C. perfringens</em> type A were investigated by molecular and bioinformatic methods.</div></div><div><h3>Results</h3><div>PLC type II contained the largest number of isolates (n = 44). The same type strains were largely clustered in the same branches. Tetracycline resistance genes <em>tetA(P)</em> and <em>tetB(P)</em> had high prevalence in type A isolates. 395 prophages were predicted including 265 “incomplete,” 55 “questionable,” and 75 “intact” prophages. CRISPR/Cas systems were more common in isolates from humans (63 %) than in those from animals and food (52 % and 46 %, respectively). Fifty-seven percent of strains likely had the tcp conjugation locus (<em>tcpC</em> to <em>tcpH</em>), and 12 isolates likely carried the conjugative pCW3 plasmid. Type A strains exhibited fewer plasmid-encoded toxins.</div></div><div><h3>Conclusions</h3><div>cgMLST analysis demonstrated some micro-evolution and regional transmission trends within type A, which exhibited partial correlated with PLC typing. This study highlights the need for enhanced surveillance of antimicrobial resistance and pathogenicity-associated MGEs in <em>C. perfringens</em> type A.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"93 ","pages":"Article 102970"},"PeriodicalIF":2.5,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143959041","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}
Diseases such as cholangitis and sinusitis may be caused by Bacteroides pyogenes, frequently isolated from patients with underlying malignancies. Head and neck infections involving B. pyogenes have high recurrence rates and may require 1–3 months of antibiotic therapy. Careful monitoring and appropriate treatment are crucial for managing these infections.
{"title":"Clinical characteristics of Bacteroides pyogenes infections: A combined analysis of 34 cases from a Japanese tertiary hospital and 29 cases from the literature","authors":"Tomonori Takano , Haruka Koji , Tadatomo Oyanagi , Hiroyuki Kunishima","doi":"10.1016/j.anaerobe.2025.102963","DOIUrl":"10.1016/j.anaerobe.2025.102963","url":null,"abstract":"<div><div>Diseases such as cholangitis and sinusitis may be caused by <em>Bacteroides pyogenes</em>, frequently isolated from patients with underlying malignancies. Head and neck infections involving <em>B. pyogenes</em> have high recurrence rates and may require 1–3 months of antibiotic therapy. Careful monitoring and appropriate treatment are crucial for managing these infections.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"93 ","pages":"Article 102963"},"PeriodicalIF":2.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143932150","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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