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POLYMERASE CHAIN REACTION USING REPETITIVE SEQUENCES (rep-PCR) AS PRIMERS TO EVALUATE Bacteroides fragilis GENETIC DIVERSITY

Moraes, S.R.¹*, Gonçalves, R.B.², Mounton, C.³, Seldin, L.¹, Ferreira, M.C.S.¹ & Domingues, R.M.C.P.¹
Instituto de Microbiologia Prof. Paulo de Góes - UFRJ1, Rio de Janeiro, Brasil; Faculdade de Odontologia de Piracicaba/UNICAMP 2, Brasil e Universite Laval3, Quebec, Canadá

Bacteroides fragilis, a component of the intestinal normal flora, is an important pathogen in non-intestinal endogenous infections. The species has been associated with enteric infections and it was already detected in polluted water. This fact suggests also a possible exogenous source to this process. In order to evaluate the B. fragilis genetic diversity a total of 41 strains were examined. This colection included strains from non-intestinal infections (20); intestinal infections (06); intestinal microbiota (05), aquatic environment (08) and two type strains (ATCC 25285 and ATCC 23745). The DNA fingerprinting was generated using two repetitive sequences (REP and ERIC) as primers by PCR. The computer-assisted sistem Taxotron®(Inst. Pasteur - Dr. P. Grimont) was utilized to analize the profile obtained and a dendrogram was generated. By using a distance of 0.32 as threshold, three clusters (hereafter referred to as genotypes I, II and III) were generated. Genotype I included 14 strains from clinical specimens, 8 strains from aquatic environmental, 5 strains from clinical intestinal material and 5 strains from intestinal microflora. Genotype II consisted of two strains of environmental aquatic and genotype III consisted of two strains which one was from clinical specimen and one from clinical intestinal material. In spite of the wide diversity of the studied strains, we could not detected an obvious correlation between a given genotype and the specific disease or healthy state of the host, or, the source of the corresponding strains.
Grants: CNPq, PRONEX, FUJB, FINEP, CEPG