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.
Subject(s)
Bacteremia/microbiology , Bacteroides Infections/microbiology , Bacteroides fragilis/genetics , Bacteroides fragilis/pathogenicity , Genomic Islands/genetics , Bacterial Toxins/genetics , Bacteroides fragilis/classification , Bacteroides fragilis/isolation & purification , Base Sequence/genetics , DNA Fingerprinting , DNA, Bacterial/chemistry , Deoxyribonucleases/chemistry , Humans , Metalloendopeptidases/genetics , Metalloproteases/genetics , Molecular Sequence Data , Polymerase Chain Reaction/methods , Sequence Analysis, DNAABSTRACT
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.
