Pattern III non-toxigenic Bacteroides fragilis (NTBF) strains in Brazil

Bacteroides fragilis strains isolated from faeces of diarrhoeic and healthy children were studied by polymerase chain reaction (PCR), in order to characterise them as enterotoxigenic B. fragilis-ETBF-if they have one of the three bft gene alleles (pattern 1) or as non-toxigenic B. fragilis-NTBF-if there was an absence of bft gene alleles and specific sites (flanking region of B. fragilis Pathogenicity Island-BfPAI) (pattern II NTBF) or absence of alleles, but the presence of this specific sites (pattern III NTBF) All strains were previously screened for cytotoxic activity ETBF was detected in 1.5% (1/66) of the samples, in which we could verify, concomitantly, the presence of Escherichia coli enteroaggregative (EAEC). Due to these data, ETBF could not be associated with diarrhoea. A large number of pattern III NTBF strains were observed, which could suggest future changes in the phenotype of enterovirulence of B. fragilis species in our country. These populations were also analysed by using AP-PCR and a great heterogeneity could be observed. We were not able to make a correlation between enterovirulence patterns and genetic types. (C) 2002 Published by Elsevier Science Ltd. All rights reserved.