The Bacteroides fragilis group is one of the most important pathogens in polymicrobial infections. The distribution of the different members of the B. fragilis group in clinical infections varies. Bacteroides fragilis accounts for 63 percent of all the group isolates, Bacteroides thetaiotaomicron for 14 percent, Bacteroides vulgatus and Bacteroides ovatus for seven percent each, Bacteroides dis...

A retrospective analysis of susceptibility data on 542 blood isolates of the Bacteroides fragilis group tested from 1987 to 1999 by the same NCCLS-recommended broth microdilution method throughout is presented. Metronidazole, beta-lactam-beta-lactamase inhibitor combinations, carbapenems, and trovafloxacin were the most active agents (susceptibility of >or=93%). Among the cephalosporin-cephamyc...

Bacteroides fragilis is the most common anaerobe isolated from clinical infections, and in this report we demonstrate a characteristic of the species that is critical to their success as an opportunistic pathogen. Among the Bacteroides spp. in the gut, B. fragilis has the unique ability of efficiently harvesting complex N-linked glycans from the glycoproteins common to serum and serous fluid. T...

The importance of gut commensal bacteria in maintaining immune homeostasis is increasingly understood. We recently described that alteration of the gut microflora can affect a population of Foxp3(+)T(reg) cells that regulate demyelination in experimental autoimmune encephalomyelitis (EAE), the experimental model of human multiple sclerosis. We now extend our previous observations on the role of...

The antibiotic susceptibility rates of 363 clinical Bacteroides fragilis group isolates collected from 17 centers in Argentina during the period from 2006 to 2009 were as follows: piperacillin-tazobactam, 99%; ampicillin-sulbactam, 92%; cefoxitin, 72%; tigecycline, 100%; moxifloxacin, 91%; and clindamycin, 52%. No metronidazole resistance was detected in these isolates during this time period. ...

Bacteroides fragilis HSP40 phages have been detected in waters with various levels of fecal contamination of human origin. The average numbers of B. fragilis phages present in sewage water reached 5.3 x 10(3) per 100 ml of water. We found a number 1,000 times lower in a river contaminated with domestic sewage only, in which the levels of fecal coliforms and fecal streptococci were 10,000 times ...

The polysaccharide capsule of Bacteroides fragilis has been shown to be important in the virulence of the organism. The capsular polysaccharide (CP) of B. fragilis has been extensively purified. Using a murine model of intraabdominal abscess formation, we have been able to demonstrate cellular immunity to the capsular polysaccharide of B. fragilis. Immunization of C57BL/10J mice with the CP ove...

The serological properties of antigens extracted from strains of Bacteroides fragilis and related species belonging to several different deoxyribonucleic acid homology groups were investigated. Antisera prepared against Formalin-treated whole cell suspensions of representative strains were tested against cell suspensions, cell wall preparations, and extracts of homologous and heterologous strai...

The in vitro antimicrobial activity of two newer agents, ticarcillin and cefoxitin, against 204 recent clinical isolates of anaerobic bacteria was determined by an agar dilution technique, and compared to their related compounds carbenicillin, cephalothin, and penicillin, as well as metronidazole, clindamycin, and chloramphenicol. Ticarcillin was similar to carbenicillin, and cefoxitin was more...

The microbiota is a major source of protection against intestinal pathogens; however, the specific bacteria and underlying mechanisms involved are not well understood. As a model of this interaction, we sought to determine whether colonization of the murine host with symbiotic non-toxigenic Bacteroides fragilis could limit acquisition of pathogenic enterotoxigenic B. fragilis We observed strain...