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Yekani M, Rezaee MA, Beheshtirouy S, Baghi HB, Bazmani A, Farzinazar A, Memar MY, Sóki J. Carbapenem resistance in Bacteroides fragilis: A review of molecular mechanisms. Anaerobe 2022; 76:102606. [PMID: 35738484 DOI: 10.1016/j.anaerobe.2022.102606] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 06/10/2022] [Accepted: 06/16/2022] [Indexed: 11/28/2022]
Abstract
Carbapenems are an applicable subclass of β-lactam drugs in the antibiotic therapy of anaerobic infections, especially for poly-microbial cases, due to their broad antimicrobial spectrum on aerobic and anaerobic bacteria. Bacteroides fragilis is the most commonly recovered anaerobic bacteria in the clinical laboratories from mono- and poly-microbial infections. B. fragilis is relatively non-susceptible to different antibiotics, including β-lactams, tetracyclines, fluoroquinolones, and macrolides. Carbapenems are among the most effective drugs against B. fragilis strains with high-level resistance to different antibiotics. Increased antibiotic resistance of B. fragilis strains has been reported following the overuse of an antimicrobial agent. Earlier contact with carbapenems is linked with increased resistance to them that limits the options for treatment of B. fragilis caused infections, especially in cases caused by multidrug-resistant strains. Several molecular mechanisms of resistance to carbapenems have been described for different carbapenem-resistant bacteria. Understanding the mechanisms of resistance to antimicrobial agents is necessary for selecting alternative antimicrobial agents and the application of control strategies. In the present study, we reviewed the mechanisms contributing to resistance to carbapenems in B. fragilis strains.
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Affiliation(s)
- Mina Yekani
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | | | - Samad Beheshtirouy
- Cardiothoracic Department, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Ahad Bazmani
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Abbas Farzinazar
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Yousef Memar
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - József Sóki
- Institute of Medical Microbiology, Albert Szent-Györgyi Health Centre and School of of Medicine, University of Szeged, Szeged, Hungary.
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Yekani M, Baghi HB, Naghili B, Vahed SZ, Sóki J, Memar MY. To resist and persist: Important factors in the pathogenesis of Bacteroides fragilis. Microb Pathog 2020; 149:104506. [PMID: 32950639 DOI: 10.1016/j.micpath.2020.104506] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/15/2020] [Accepted: 09/15/2020] [Indexed: 02/07/2023]
Abstract
Bacteroides fragilis is a most frequent anaerobic pathogen isolated from human infections, particularly found in the abdominal cavity. Different factors contribute to the pathogenesis and persistence of B. fragilis at infection sites. The knowledge of the virulence factors can provide applicable information for finding alternative options for the antibiotic therapy and treatment of B. fragilis caused infections. Herein, a comprehensive review of the important B. fragilis virulence factors was prepared. In addition to B. fragilis toxin (BFT) and its potential role in the diarrhea and cancer development, some other important virulence factors and characteristics of B. fragilis are described including capsular polysaccharides, iron acquisition, resistance to antimicrobial agents, and survival during the prolonged oxidative stress, quorum sensing, and secretion systems.
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Affiliation(s)
- Mina Yekani
- Department of Microbiology, Faculty of Medicine, Kashan University of Medical Sciences, Kashan, Iran; Student Research Committee,Kashan University of Medical Sciences, Kashan, Iran
| | - Hossein Bannazadeh Baghi
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Behrooz Naghili
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - József Sóki
- Institute of Clinical Microbiology, Faculty of Medicine, University of Szeged, Szeged, Hungary.
| | - Mohammad Yousef Memar
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Microbiology Department, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran; Students' Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.
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Drewes JL, Corona A, Sanchez U, Fan Y, Hourigan SK, Weidner M, Sidhu SD, Simner PJ, Wang H, Timp W, Oliva-Hemker M, Sears CL. Transmission and clearance of potential procarcinogenic bacteria during fecal microbiota transplantation for recurrent Clostridioides difficile. JCI Insight 2019; 4:130848. [PMID: 31578306 DOI: 10.1172/jci.insight.130848] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 09/04/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUNDFecal microbiota transplantation (FMT) is an effective treatment for recurrent Clostridioides difficile infection (rCDI) in adults and children, but donor stool samples are currently screened for only a limited number of potential pathogens. We sought to determine whether putative procarcinogenic bacteria (enterotoxigenic Bacteroides fragilis, Fusobacterium nucleatum, and Escherichia coli harboring the colibactin toxin) could be durably transmitted from donors to patients during FMT.METHODSStool samples were collected from 11 pediatric rCDI patients and their respective FMT donors prior to FMT as well as from the patients at 2-10 weeks, 10-20 weeks, and 6 months after FMT. Bacterial virulence factors in stool DNA extracts and stool cultures were measured by quantitative PCR: Bacteroides fragilis toxin (bft), Fusobacterium adhesin A (fadA), and Escherichia coli colibactin (clbB).RESULTSFour of 11 patients demonstrated sustained acquisition of a procarcinogenic bacteria. Whole genome sequencing was performed on colony isolates from one of these donor/recipient pairs and demonstrated that clbB+ E. coli strains present in the recipient after FMT were identical to a strain present in the donor, confirming strain transmission. Conversely, 2 patients exhibited clearance of procarcinogenic bacteria following FMT from a negative donor.CONCLUSIONBoth durable transmission and clearance of procarcinogenic bacteria occurred following FMT, suggesting that additional studies on appropriate screening measures for FMT donors and the long-term consequences and/or benefits of FMT are warranted.FUNDINGCrohn's & Colitis Foundation, the Bloomberg~Kimmel Institute for Cancer Immunotherapy at Johns Hopkins University School of Medicine, the National Cancer Institute, and the Canadian Institutes of Health Research.
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Affiliation(s)
- Julia L Drewes
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Alina Corona
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Uriel Sanchez
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Yunfan Fan
- Department of Biomedical Engineering, Johns Hopkins University Whiting School of Engineering, Baltimore, Maryland, USA
| | - Suchitra K Hourigan
- Division of Pediatric Gastroenterology, Hepatology and Nutrition, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Melissa Weidner
- Division of Pediatric Gastroenterology, Hepatology and Nutrition, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Sarah D Sidhu
- Division of Pediatric Gastroenterology, Hepatology and Nutrition, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | | - Hao Wang
- Department of Oncology, Bioinformatics and Biostatistics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Winston Timp
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Biomedical Engineering, Johns Hopkins University Whiting School of Engineering, Baltimore, Maryland, USA
| | - Maria Oliva-Hemker
- Division of Pediatric Gastroenterology, Hepatology and Nutrition, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Cynthia L Sears
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Bloomberg-Kimmel Institute for Immunotherapy, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Keenan JI, Aitchison A, Purcell RV, Greenlees R, Pearson JF, Frizelle FA. Screening for enterotoxigenic Bacteroides fragilis in stool samples. Anaerobe 2016; 40:50-3. [PMID: 27166180 DOI: 10.1016/j.anaerobe.2016.05.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/21/2016] [Accepted: 05/06/2016] [Indexed: 02/08/2023]
Abstract
Bacteroides fragilis is a commensal bacterium found in the gut of most humans, however enterotoxigenic B. fragilis strains (ETBF) have been associated with diarrhoea and colorectal cancer (CRC). The purpose of this study was to establish a method of screening for the Bacteroides fragilis toxin (bft) gene in stool samples, as a means of determining if carriage of ETBF is detected more often in CRC patients than in age-matched healthy controls. Stool samples from 71 patients recently diagnosed with CRC, and 71 age-matched controls, were screened by standard and quantitative PCR using primers specific for the detection of the bft gene. Bacterial template DNA from stool samples was prepared by two methods: a sweep, where all colonies growing on Bacteroides Bile Esculin agar following stool culture for 48 h at 37 °C in an anaerobic environment were swept into sterile water and heat treated; and a direct DNA extraction from each stool sample. The bft gene was detected more frequently from DNA isolated from bacterial sweeps than from matched direct DNA extractions. qPCR was found to be more sensitive than standard PCR in detecting bft. The cumulative total of positive qPCR assays from both sample types revealed that 19 of the CRC patients had evidence of the toxin gene in their stool sample (27%), compared to seven of the age-matched controls (10%). This difference was significant (P = 0.016). Overall, ETBF carriage was detected more often in CRC patient stool samples compared to controls, but disparate findings from the different DNA preparations and testing methods suggests that poor sensitivity may limit molecular detection of ETBF in stool samples.
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Affiliation(s)
- Jacqueline I Keenan
- Department of Surgery, University of Otago Christchurch, Christchurch, New Zealand.
| | - Alan Aitchison
- Department of Surgery, University of Otago Christchurch, Christchurch, New Zealand
| | - Rachel V Purcell
- Department of Surgery, University of Otago Christchurch, Christchurch, New Zealand
| | - Rosie Greenlees
- Microbiology Department, Canterbury Health Laboratories, Christchurch, New Zealand
| | - John F Pearson
- Biostatistics and Computational Biology Unit, University of Otago Christchurch, Christchurch, New Zealand
| | - Frank A Frizelle
- Department of Surgery, University of Otago Christchurch, Christchurch, New Zealand
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Chen LA, Van Meerbeke S, Albesiano E, Goodwin A, Wu S, Yu H, Carroll K, Sears C. Fecal detection of enterotoxigenic Bacteroides fragilis. Eur J Clin Microbiol Infect Dis 2015; 34:1871-7. [PMID: 26173688 DOI: 10.1007/s10096-015-2425-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 06/04/2015] [Indexed: 01/14/2023]
Abstract
Bacteroides fragilis is a common colonic symbiote of which one subtype, enterotoxigenic Bacteroides fragilis (ETBF), causes inflammatory diarrhea. However, asymptomatic ETBF colonization is common. Through its primary virulence factor, B. fragilis toxin (BFT), ETBF causes asymptomatic, chronic colitis in C57BL/6 mice and increased colon tumorigenesis in multiple intestinal neoplasia mice. Human studies suggest an association between ETBF infection, inflammatory bowel disease, and colon cancer. Additional studies on ETBF epidemiology are, therefore, crucial. The goal of this study is to develop a reliable fecal diagnostic for ETBF. To develop a sensitive assay for ETBF, we tested multiple protocols on mouse stools spiked with serially diluted ETBF. Each assay was based on either touchdown or quantitative polymerase chain reaction (qPCR) and used primers targeted to bft to detect ETBF. Using touchdown PCR or qPCR, the mean ETBF detection limit was 1.55 × 10(6) colony-forming units (CFU)/g stool and 1.33 × 10(4) CFU/g stool, respectively. Augmentation of Bacteroides spp. growth in fecal samples using PYGB (Peptone Yeast Glucose with Bile) broth enhanced ETBF detection to 2.93 × 10(2) CFU/g stool using the touchdown PCR method and 2.63 × 10(2) CFU/g stool using the qPCR method. Fecal testing using combined culture-based amplification and bft touchdown PCR is a sensitive assay for the detection of ETBF colonization and should be useful in studying the role of ETBF colonization in intestinal diseases, such as inflammatory bowel disease and colon cancer. We conclude that touchdown PCR with culture-based amplification may be the optimal ETBF detection strategy, as it performs as well as qPCR with culture-based amplification, but is a less expensive technique.
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Affiliation(s)
- L A Chen
- Department of Medicine, Johns Hopkins School of Medicine, CRB2 Bldg, Suite 1M.05, 1550 Orleans Street, Baltimore, MD, 21231, USA
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Evaluation of the prevalence of enterotoxigenic Bacteroides fragilis and the distribution bft gene subtypes in patients with diarrhea. Anaerobe 2010; 16:505-9. [PMID: 20709181 DOI: 10.1016/j.anaerobe.2010.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 07/14/2010] [Accepted: 08/05/2010] [Indexed: 11/22/2022]
Abstract
The aim of this study was to determine the prevalence of enterotoxigenic Bacteroides fragilis (ETBF) in the patients with diarrhea in our region and to assess the association between diarrhea and bft gene subtypes. The presence of ETBF and bft gene subtypes were investigated in 200 stool samples from patients with diarrhea, diagnosed as gastroenteritis, which were sent to Clinical Microbiology Laboratory at Zonguldak Karaelmas University, Training and Research Hospital and in 200 stool samples from age-matched healthy subjects between April 14, 2009 and October 28, 2009. Nested - polymerase chain reaction was used to detect the presence of bft gene directly from stool samples. The bft gene subtypes were determined by PCR in case of ETBF detection. The presence of bft gene was detected in 29 (15%) of patients and 27 (14%) of control group. bft-1 and bft-2 were found in 24 and five stool samples from 29 diarrheic patients with ETBF, respectively. Among 27 control patients with ETBF, bft-1 and bft-2 were found in 24 and three samples, respectively. No bft-3 subtypes were identified in our study. ETBF was found as a single pathogen in 9% of the patients with diarrhea, while there was an accompanying pathogen in 6% of the patients. The proportion of coinfection with another pathogen among ETBF positive patients was 38%. Cooccurance with ETBF was present in nine of 18 patients with Rotavirus and two of five patients with Entamoeba histolytica. In conclusion; there was no statistically significant difference between the prevalence of ETBF in diarrheal patients and that of the control group. When the patients and controls were compared for each age group, no statistically significant difference in ETBF rates was found. There was no significant difference between groups with respect to bft subtypes; bft-1 was identified as the most common subtype. The rate of coinfection of ETBF and Rotavirus was high.
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Enterotoxigenic Bacteroides fragilis: a rogue among symbiotes. Clin Microbiol Rev 2009; 22:349-69, Table of Contents. [PMID: 19366918 DOI: 10.1128/cmr.00053-08] [Citation(s) in RCA: 264] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Enterotoxigenic Bacteroides fragilis (ETBF) strains are strains of B. fragilis that secrete a 20-kDa heat-labile zinc-dependent metalloprotease toxin termed the B. fragilis toxin (BFT). BFT is the only recognized virulence factor specific for ETBF. ETBF strains are associated with inflammatory diarrheal disease in children older than 1 year of age and in adults; limited data suggest an association of ETBF colonization with inflammatory bowel disease flare-ups and colorectal cancer. ETBF secretes one of three highly related BFT isoforms. The relationship between BFT isoform and disease expression is unknown. Although the mechanism of action of BFT is incompletely understood, available data suggest that BFT binds to a specific intestinal epithelial cell receptor, stimulating intestinal cell signal transduction pathways that result in cell morphology changes, cleavage of E-cadherin, reduced colonic barrier function, and increased epithelial cell proliferation and cytokine expression (such as the proinflammatory chemokine interleukin-8). Together, the data suggest that in some hosts, ETBF acts via secretion of BFT to induce colitis. However, the full spectrum of clinical disease related to ETBF and the impact of chronic ETBF colonization on the host remain to be defined.
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Meraz IM, Jiang ZD, Ericsson CD, Bourgeois AL, Steffen R, Taylor DN, Hernandez N, DuPont HL. Enterotoxigenic Escherichia coli and diffusely adherent E. coli as likely causes of a proportion of pathogen-negative travelers' diarrhea--a PCR-based study. J Travel Med 2008; 15:412-8. [PMID: 19090795 DOI: 10.1111/j.1708-8305.2008.00249.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Enteropathogens cannot be identified in 40% to 50% of subjects with travelers' diarrhea (TD). METHODS We used polymerase chain reaction (PCR) methods to look for the presence of two bacterial causes of diarrhea in a large group of international travelers after failing to detect a pathogen by conventional tests. DNA was isolated from the diarrheal stool and subjected to PCR from 162 subjects from whom we earlier failed to identify a pathogen in a previous study and included 54 from Antigua, Guatemala, 39 from Guadalajara, Mexico, 29 from Kolkata, India, and 40 from Goa, India. Gene products for enterotoxigenic Escherichia coli (ETEC)--LT (heat-labile enterotoxin) and ST (heat-stable enterotoxin)--and diffusely adherent E. coli (DAEC), afa/dr (Afa fimbrial and Dr nonfimbrial family of adhesins), were used. RESULTS At least one gene product was identified in diarrhea stool samples of 47 of 162 (29%) subjects. ETEC virulence genes (LT, ST) were found in 34 (21%) samples studied, with rates of occurrence ranging from 8% in Goa to 39% for the samples from Guatemala (p = 0.0006). A large number of ST-only strains explained the high ETEC rate in Guatemala. DAEC afa/dr family of adhesions was identified in between 8 and 14% of the samples. CONCLUSIONS ETEC and DAEC were implicated in nearly one-third of the subjects initially diagnosed as pathogen negative. Direct PCR results from stools are consistent with the previous assumption that most undiagnosed TD is bacterial in nature and also highlights the potential value that PCR can add to studies designed to evaluate treatment and preventive interventions for TD, including vaccines.
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Affiliation(s)
- Ismail M Meraz
- School of Public Health, University of Texas, Houston, TX 77030, USA
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Abstract
SUMMARY Bacteroides species are significant clinical pathogens and are found in most anaerobic infections, with an associated mortality of more than 19%. The bacteria maintain a complex and generally beneficial relationship with the host when retained in the gut, but when they escape this environment they can cause significant pathology, including bacteremia and abscess formation in multiple body sites. Genomic and proteomic analyses have vastly added to our understanding of the manner in which Bacteroides species adapt to, and thrive in, the human gut. A few examples are (i) complex systems to sense and adapt to nutrient availability, (ii) multiple pump systems to expel toxic substances, and (iii) the ability to influence the host immune system so that it controls other (competing) pathogens. B. fragilis, which accounts for only 0.5% of the human colonic flora, is the most commonly isolated anaerobic pathogen due, in part, to its potent virulence factors. Species of the genus Bacteroides have the most antibiotic resistance mechanisms and the highest resistance rates of all anaerobic pathogens. Clinically, Bacteroides species have exhibited increasing resistance to many antibiotics, including cefoxitin, clindamycin, metronidazole, carbapenems, and fluoroquinolones (e.g., gatifloxacin, levofloxacin, and moxifloxacin).
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Baums IB, Goodwin KD, Kiesling T, Wanless D, Fell JW. Luminex detection of fecal indicators in river samples, marine recreational water, and beach sand. MARINE POLLUTION BULLETIN 2007; 54:521-36. [PMID: 17350051 PMCID: PMC1950674 DOI: 10.1016/j.marpolbul.2006.12.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2006] [Revised: 12/14/2006] [Accepted: 12/19/2006] [Indexed: 05/06/2023]
Abstract
Research to understand and remediate coastal pollution is moving toward a multitiered approach in which traditional enumeration of fecal indicators is accompanied by molecular analysis of a variety of targets. Technology that rapidly detects multiple microbial contaminants would benefit from such an approach. The Luminex 100 system is a suspension array that assays multiple analytes rapidly in a single well of a microtiter plate. The ability of the system to simultaneously detect multiple fecal indicating bacteria in environmental samples was tested. Primer/probe sets were designed to simultaneously detect the following fecal indicators: the Bacteroides fragilis group, Enterococcus spp., Escherichia coli and Shigella spp., Bacteroides distasonis, and Ent. faecalis. Specificity and sensitivity of the Luminex probes was tested against laboratory cultures. In addition, sequencing, culture plate testing, and specificity testing with environmental isolates were steps taken to validate the function of the assay with environmental samples. Luminex response to cultures and to environmental samples was consistent with sequencing results, suggesting that the technology has the potential to simultaneously detect multiple targets for coastal water quality applications, particularly as progress is made to efficiently extract DNA from water and sediment matrices.
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Affiliation(s)
- Iliana B. Baums
- Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA
| | - Kelly D. Goodwin
- National Oceanographic and Atmospheric Administration, Atlantic Oceanographic and Meteorological Laboratory, Ocean Chemistry Division, Miami, FL 33149, USA
- * Corresponding author. NOAA/AOML/Ocean Chemistry Division, 4301 Rickenbacker Causeway, Miami, FL 33149, USA. Tel.: +1 305 361 4384; fax:+1 305 361 4447. E-mail address:
| | - Traci Kiesling
- Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA
| | - David Wanless
- Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA
| | - Jack W. Fell
- Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA
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Cohen SH, Shetab R, Tang-Feldman YJ, Sarma P, Silva J, Prindiville TP. Prevalence of enterotoxigenic Bacteroides fragilis in hospital-acquired diarrhea. Diagn Microbiol Infect Dis 2006; 55:251-4. [PMID: 16650957 DOI: 10.1016/j.diagmicrobio.2006.01.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2005] [Revised: 01/06/2006] [Accepted: 01/18/2006] [Indexed: 11/20/2022]
Abstract
Stool specimens from 152 hospitalized patients with diarrhea were analyzed for the presence of enterotoxigenic Bacteroides fragilis (ETBF) by a nested polymerase chain reaction (PCR) assay. ETBF gene sequences were directly detected in 14/152 (9.21%) stools of patients. The prevalence of ETBF in hospital-acquired diarrhea was statistically significant when compared to a prevalence of 2.3% in control subjects (P = 0.04). B. fragilis was cultured from 19.7% (30/152) patients with diarrhea; 4 of these isolates were enterotoxigenic. To determine whether colonization with B. fragilis is heterogeneous in nature, multiple colonies from 17 individual patients were analyzed for enterotoxin gene sequences and genotyped by arbitrarily primed PCR. Of these 17 patients, 13 harbored multiple strain types suggesting heterogeneity of colonization with both enterotoxigenic and non-enterotoxigenic strains. Identification of ETBF in the stools of 10 patients in the absence of a positive culture is likely due to the noted heterogeneity and suggests that detection of enterotoxin by PCR should be performed directly in the stool. These preliminary data indicate that ETBF may play a role in hospital-acquired diarrhea of unknown origin and suggest the need for further studies.
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Affiliation(s)
- Stuart H Cohen
- Division of Infectious and Immunologic Diseases, Department of Internal Medicine, University of California, Davis Medical Center, Sacramento, CA 95817, USA.
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Claros MC, Claros ZC, Hecht DW, Citron DM, Goldstein EJC, Silva J, Tang-Feldman Y, Rodloff AC. Characterization of the Bacteroides fragilis pathogenicity island in human blood culture isolates. Anaerobe 2005; 12:17-22. [PMID: 16701608 DOI: 10.1016/j.anaerobe.2005.06.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2004] [Revised: 06/15/2005] [Accepted: 06/15/2005] [Indexed: 11/20/2022]
Abstract
Bacteroides fragilis is an important anaerobic pathogen accounting for up to 10% of bacteremias in adult patients. Enterotoxin producing B. fragilis (ETBF) strains have been identified as enteric pathogens of children and adults. In order to further characterize the B. fragilis pathogenicity island (BfPAI) and using PCR assays for bft- and mpII-metalloprotease genes, we determined the frequency of B. fragilis strains with pattern I (containing the BfPAI and its flanking region), pattern II (lacking both the BfPAI and the flanking region), and pattern III (lacking the BfPAI but containing the flanking region) in 63 blood culture isolates. The results were compared to 197 B. fragilis isolates from different clinical sources. We found 19% of blood culture isolates were pattern I (ETBF), 43% were pattern II (NTBF) and 38% were pattern III (NTBF). Comparatively, B. fragilis isolates from other clinical sources were 10% pattern I, 47% pattern II and 43% pattern III. This suggests that the pathogenicity island and the flanking elements may be general virulence factors of B. fragilis.
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Affiliation(s)
- M C Claros
- Institute of Medical Microbiology and Infectious Epidemiology, University of Leipzig, Germany.
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13
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Durmaz B, Dalgalar M, Durmaz R. Prevalence of enterotoxigenic Bacteroides fragilis in patients with diarrhea: a controlled study. Anaerobe 2005; 11:318-21. [PMID: 16701593 DOI: 10.1016/j.anaerobe.2005.06.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Revised: 05/13/2005] [Accepted: 06/01/2005] [Indexed: 11/22/2022]
Abstract
In this age matched controlled study performed in Malatya, a city in east region of Turkey, enterotoxigenic Bacteroides fragilis (ETBF) was investigated in stool specimens obtained from children and adults with and without diarrhea. A nested polymerase chain reaction (PCR) method was used to detect the enterotoxin gene of B. fragilis in a total of 418 stool samples, including 221 samples from 117 children (aged 0-16 years) and 104 adults (aged >16 years) with diarrhea, and 197 samples from 102 children and 95 adults as control group that was the same age group with those having diarrhea. ETBF was detected in 13 of 117 diarrheal children (11.1%) and 8 of 102 control children (7.8%) (P>0.05). In children aged 1-5 years, the rate of ETBF was significantly higher in patients than in controls (25% versus 9.5%, respectively; P<0.05). On the other hand ETBF was detected similar rates (2.2% and 2.4%, respectively) in children younger than 1 year in both patients and controls. ETBF positivity was not significantly difference between patient and control groups who were older than 5 years of age and adults. The frequency of ETBF in the controls was slightly higher in older persons than in younger ones; however, it was not significant. The rate of ETBF as the only enteropathogen in the patients with ETBF was significantly higher than in controls with ETBF (88% versus 39%, respectively; P<0.02). We found that in east region of Turkey, the prevalence of ETBF was higher in the childhood diarrhea, particularly in aged 1-5. As the only enteropathogen, ETBF may play an important role in diarrheal diseases. Persons after 6 years old can be carrier for ETBF regardless diarrhea.
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Affiliation(s)
- Bengul Durmaz
- Faculty of Medicine, Department of Clinical Microbiology, Inonu University, 44069 Malatya, Turkey.
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Vu Nguyen T, Le Van P, Le Huy C, Weintraub A. Diarrhea caused by enterotoxigenic Bacteroides fragilis in children less than 5 years of age in Hanoi, Vietnam. Anaerobe 2004; 11:109-14. [PMID: 16701540 DOI: 10.1016/j.anaerobe.2004.10.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Revised: 10/04/2004] [Accepted: 10/05/2004] [Indexed: 10/26/2022]
Abstract
Enterotoxigenic Bacteroides fragilis (ETBF) are considered as an emerging enteropathogen causing diarrhea in children. Eight hundred and thirty-six (836) children less than 5 years of age including 587 children with diarrhea and 249 age-matched controls were involved in the study. Within the group of children with diarrhea, 7.3% (43/587) ETBF was detected by immunoseparation in combination with polymerase chain reaction. The corresponding figure for the controls was 2.4% (6/249) (P<0.01). Within the diarrhea group, the prevalence was significantly higher in children older than 1 year of age. Three subtypes of ETBF isolates have been identified with the prevalence of 67.4%, 18.6%, and 16% for bft-1, bft-2, and a new bft, respectively. In the controls, two of the subtypes were identified, 5 bft-1 and 1 bft-2. More than half (55.8%) of the samples harboring ETBF also had other identified pathogens. The clinical symptoms of the single ETBF infection were not different from those of co-infections. This is the first study of the role of ETBF in children's diarrhea in Vietnam and it is concluded that this pathogen is an important causative agent of diarrhea in children in Hanoi, Vietnam.
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Affiliation(s)
- Trung Vu Nguyen
- Department of Medical Microbiology, Hanoi Medical University, Hanoi, Vietnam
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15
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Basset C, Holton J, Bazeos A, Vaira D, Bloom S. Are Helicobacter species and enterotoxigenic Bacteroides fragilis involved in inflammatory bowel disease? Dig Dis Sci 2004; 49:1425-32. [PMID: 15481314 DOI: 10.1023/b:ddas.0000042241.13489.88] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The aim of this study was to determine if either Helicobacter or enterotoxigenic Bacteroidesfragilis (ETBF) was linked to inflammatory bowel disease (IBD), using PCR. We analyzed the luminal washings and colonic biopsies of 35 patients with IBD and 37 control patients. The presence of Helicobacter was confirmed in the luminal washing of one IBD patient and three control patients and in the biopsies of two IBD patients. Ten of 28 control patients and 8 of 32 IBD patients had a positive luminal washing for the enterotoxin gene. Six of 33 control patients and 4 of 32 IBD patients had positive biopsies. The prevalence of the enterotoxin gene was higher in IBD patients with active disease compared with patients with inactive disease, although it did not achieve statistical significance. In conclusion, Helicobacter was not associated with IBD in our population of patients, although ETBF may be associated with active disease.
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Affiliation(s)
- Christelle Basset
- Centre for Infectious Diseases and International Health, Windeyer Institute of Medical Sciences, Royal Free & University College London Medical School, The Windeyer Building, 46 Cleveland Street, London WIT 4JF, United Kingdom
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16
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Holland JL, Louie L, Simor AE, Louie M. PCR detection of Escherichia coli O157:H7 directly from stools: evaluation of commercial extraction methods for purifying fecal DNA. J Clin Microbiol 2000; 38:4108-13. [PMID: 11060076 PMCID: PMC87549 DOI: 10.1128/jcm.38.11.4108-4113.2000] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rapid identification of Escherichia coli O157:H7 is important for patient management and for prompt epidemiological investigations. We evaluated one in-house method and three commercially available kits for their ability to extract E. coli O157:H7 DNA directly from stool specimens for PCR. Of the 153 stool specimens tested, 107 were culture positive and 46 were culture negative. The sensitivities and specificities of the in-house enrichment method, IsoQuick kit, NucliSens kit, and QIAamp kit were comparable, as follows: 83 and 98%, 85 and 100%, 74 and 98%, and 86 and 100%, respectively. False-negative PCR results may be due to the presence of either inherent inhibitors or small numbers of organisms. The presence of large amounts of bacteria relative to the amount of the E. coli O157:H7 target may result in the lower sensitivities of the assays. All commercial kits were rapid and easy to use, although DNA extracted with the QIAamp kit did not require further dilution of the DNA template prior to PCR.
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Affiliation(s)
- J L Holland
- Department of Microbiology, Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario, Canada
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17
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Sarma PN, Tang YJ, Prindiville TP, Osborne PD, Jang S, Silva J, Cohen SH. Genotyping of Bacteroides fragilis isolates from stool specimens by arbitrarily-primed-PCR. Diagn Microbiol Infect Dis 2000; 37:225-9. [PMID: 10974572 DOI: 10.1016/s0732-8893(00)00150-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In order to determine genetic relatedness of Bacteroides fragilis isolates from different clinical sources, arbitrarily primed polymerase chain reaction (PCR) (AP-PCR) was used to compare 17 strains isolated from patients with inflammatory bowel disease (IBD) and 20 strains isolated from foals with diarrhea. Three reference ATCC strains were also analyzed. Eighteen unique types were identified with a 22-mer arbitrary primer (ERIC-2) among the 20 patient isolates. Types 1 (enterotoxigenic) and 9 (nonenterotoxigenic), were each found in the stools of two patients. All other isolates showed a distinct and unique DNA banding pattern indicating a high degree of genotypic variability. Eleven types were identified among the foal isolates. Type 20, a nonenterotoxigenic type, was present in 30% of the foals. No correlation was found between the human and horse isolates. No clear relationship between a disease state (diarrhea or IBD) and specific types was observed. AP-PCR will be useful as a rapid method to determine genetic relatedness and in future epidemiologic studies of diarrheal diseases due to B. fragilis.
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Affiliation(s)
- P N Sarma
- Department of Internal Medicine, Division of Infectious and Immunologic Diseases, University of California, Davis Medical Center, Sacramento, CA 95817, USA
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18
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Claros MC, Claros ZC, Tang YJ, Cohen SH, Silva J, Goldstein EJ, Rodloff AC. Occurrence of Bacteroides fragilis enterotoxin gene-carrying strains in Germany and the United States. J Clin Microbiol 2000; 38:1996-7. [PMID: 10790139 PMCID: PMC86649 DOI: 10.1128/jcm.38.5.1996-1997.2000] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ninety-three Bacteroides fragilis isolates from different geographic locations were analyzed for the presence of an enterotoxin-encoding gene. It was shown that blood culture isolates were more likely to carry this gene than strains from other sources. All enterotoxin-positive strains belonged to the PCR fingerprint group I.
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Affiliation(s)
- M C Claros
- Institute of Medical Microbiology and Infectious Epidemiology, University of Leipzig, Leipzig, Germany.
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19
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Carlier J, Henry C, Touil N, Lorin V, Popoff M. Détection systématique des souches de Bacteroides fragilis entérotoxinogènes. Med Mal Infect 2000. [DOI: 10.1016/s0399-077x(00)88783-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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20
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Prindiville TP, Sheikh RA, Cohen SH, Tang YJ, Cantrell MC, Silva J. Bacteroides fragilis enterotoxin gene sequences in patients with inflammatory bowel disease. Emerg Infect Dis 2000; 6:171-4. [PMID: 10756151 PMCID: PMC2640860 DOI: 10.3201/eid0602.000210] [Citation(s) in RCA: 148] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We identified enterotoxigenic Bacteroides fragilis in stool specimens of patients with inflammatory bowel disease and other gastrointestinal disorders. The organism was detected in 11 (13.2%) of 83 patients with inflammatory bowel disease. Of 57 patients with active disease, 19.3% were toxin positive; none of those with inactive disease had specimens positive for enterotoxigenic Bacteroides fragilis gene sequences.
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Affiliation(s)
- T P Prindiville
- University of California, Davis Medical Center, Sacramento, CA, USA
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21
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Zhang G, Weintraub A. Rapid and sensitive assay for detection of enterotoxigenic Bacteroides fragilis. J Clin Microbiol 1998; 36:3545-8. [PMID: 9817870 PMCID: PMC105237 DOI: 10.1128/jcm.36.12.3545-3548.1998] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteroides fragilis is an obligatory anaerobic, gram-negative bacterium found among the normal intestinal flora of humans. Enterotoxigenic strains of B. fragilis (ETBF) have been associated with diarrheal diseases in humans and animals. The enterotoxin of ETBF induces fluid changes in ligated intestinal segments and cytotoxic response in HT29/C1 cells. By using a pair of monoclonal antibodies (MAbs; MAb C3 and MAb 4H8) specific for the lipopolysaccharide of B. fragilis, an assay based on immunomagnetic separation (IMS) in combination with PCR (IMS-PCR) was developed. After DNA extraction, a 294-bp fragment was amplified. The specificity of the IMS-PCR assay was evaluated by adding previously isolated and confirmed ETBF strains to normal fecal samples. All fecal samples to which ETBF strains were added were positive, showing a 100% specificity. The spiked fecal samples were also used for evaluation of the sensitivity of the assay. The detection limit was found to be approximately 50 CFU/g of feces. By this method 10 clinical fecal samples (5 from patients with diarrhea and 5 from healthy controls) were examined. The results of PCR were in accordance with the results of the HT29/C1 cell assay for all samples. The minimum time to retrieval of the final result by the IMS-PCR method is 36 h. The proposed IMS-PCR assay is rapid and sensitive for the direct detection of ETBF in stool samples.
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Affiliation(s)
- G Zhang
- Department of Immunology, Microbiology, Pathology and Infectious Diseases, Division of Clinical and Oral Bacteriology, Huddinge University Hospital, Karolinska Institute, S-141 86 Huddinge, Sweden
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