Use of rep-PCR to define genetic relatedness among Bacteroides fragilis strains

Instituto de Microbiologia Prof. Paulo de Góes, UFRJ, Rio de Janeiro, Brasil *Faculdade de Odontologia de Piracicaba/UNICAMP, Brasil and Faculté de Medicine Dentaire, Universite Laval, Quebec, Canada Corresponding author: Professor R. M. C. P. Domingues (e-mail: IMMMREG{at}microbio.UFRJ.br ). Received 17 Feb. 1999; revised version received 10 Aug. 1999; accepted 13 Aug. 1999. Abstract Bacteroides fragilis , a component of the normal flora and an important anaerobic pathogen in non-intestinal endogenous infections, has recently been associated with enteric diseases. In this study, 41 B. fragilis strains were analysed in relation to their genetic diversity. This collection included two reference strains (ATCC 23745 and 25285), 20 isolates from non-intestinal infections, six from intestinal infections, five from intestinal microflora and eight from an aquatic environment. The fingerprints were generated by using two repetitive sequences (REP and ERIC) as primers to PCR (rep-PCR). A dendrogram was obtained with the Taxotron® Program. Three clusters (threshold genotypes I, II and III) were observed when the genetic distance was 0.30. These results confirm previous data found regarding the genotypical diversity of B. fragilis .