Intra-abdominal infections (IAI) continue to be a serious clinical problem. Bacterial synergism is an important factor that influences the shift from contamination to IAI, leading to the development of lesions and abscess formation. Escherichia coli and Bacteroides fragilis are particularly abundant in IAI. The underlying molecular mechanisms of this pathogenic synergy are still unclear. The ro...

Ever since its first description in 1918, Dientamoeba fragilis has struggled to gain recognition as a significant pathogen. There is little justification for this neglect, however, since there exists a growing body of case reports from numerous countries around the world that have linked this protozoal parasite to clinical manifestations such as diarrhea, abdominal pain, flatulence, and anorexi...

Bacteroides fragilis has been isolated from several human and non-human monomicrobial and mixed infections. In this study, some virulence markers and the antimicrobial susceptibility of bacteria of the B. fragilis group isolated from children's stools were evaluated. All the 64 isolates showed the following characteristics: capsulated, beta-hemolytic, hydrophilic, and serum-resistant. Only, 24 ...

In response to phosphate limitation, bacteria employ the Pho regulon, a specific regulatory network for phosphate acquisition. The two-component signal transduction system of PhoRB plays a crucial role in the induction of Pho regulon genes, leading to the adaptation to phosphate starvation. Herein, we identified the PhoRB system in Bacteroides fragilis, a commensal gut bacterium, and evaluated ...

A selective medium was developed for the isolation of Bacteroides fragilis directly from ovine and bovine fecal samples. The medium (tryptose blood agar plus polymyxin B, triclosan (Irgasan), novobiocin, and nalidixic acid) permitted growth of B. fragilis and several other species of Bacteroides but inhibited growth of most other intestinal bacteria.

The activity of a fourth conserved tyrosine site-specific recombinase (Tsr) of Bacteroides fragilis was characterized. Its gene, tsr19, is adjacent to mpi, encoding the global DNA invertase regulating capsular polysaccharide biosynthesis. Unlike the other described Tsrs of B. fragilis, Tsr19 brings about inversion of two DNA regions, one local and one located distantly.

We investigated associations of species of the Bacteroides fragilis group with Japanese cedar pollinosis (JCPsis). Cell numbers of Bacteroides fragilis and Bacteroides intestinalis were significantly higher in JCPsis subjects than in non-JCPsis subjects before the pollen season. They correlated positively with both symptom scores and JCPsis-specific immunoglobulin E levels.

The genome of Youngiibacter fragilis, the type strain of the newly described genus Youngiibacter, was sequenced. The genome consists of 3.996 Mb, with a G+C content of 46.6 mol%. Y. fragilis originates from coal-bed methane-produced water and may provide insight into the microbiological basis of biogas production in coal beds.

The activity of MK-0826, a new carbapenem, against 309 Bacteroides fragilis group strains was investigated and compared with that of 11 other beta-lactam and 5 non-beta-lactam agents. MK-0826 showed excellent activity (MICs ranged from < or =0.06 to 4 microg/ml). The new carbapenem may be useful in the treatment of mixed anaerobic infections involving B. fragilis group strains.

A beta-lactamase isolated from a strain of Bacteroides fragilis subsp. fragilis possessed hydrolytic activity toward cefotaxime. This antibiotic was degraded to a lower extent than was cephalothin, cephaloridine, and cefamandole, whereas cefoxitin remained unaffected by the enzyme. Kinetic parameters Vmax and Km for cefotaxime were calculated at 0.172 mumol/min and 1.1 X 10(-2) mM, respectively.