Bacteroides fragilis isolates compared by AP-PCR

Bacteroides fragilis is a component of the normal intestinal flora and an i mportant pathogen in nonintestinal endogenous infections. It has been assoc iated with enteric infections and has already been detected in polluted wat er. In order to evaluate the genetic diversity of B. fragilis, a total of 3 1 isolates and two reference strains were examined. This collection include d strains from nonintestinal infections [12], intestinal infections [5], in testinal microflora [10], aquatic environments [4], and the reference strai ns ATCC 25285 and ATCC 23745. DNA fingerprints were detected using two sepa rate PCR reactions with different arbitrary primers. The computer-assisted system Taxotron(R) (Institut Pasteur, Dr P. Grimont) was used to analyze th e profiles obtained and dendrograms were generated. By using a distance of 0.65 as the threshold, two clusters (hereafter referred to as genotypes I a nd II) were defined. Strains of differents origins could be distributed int o both genotypes. We were unable to detect any obvious correlation between a given genotype and the specific disease or the source of the correspondin g strains. (C) Elsevier, Paris.