title: Presence of the cfxA gene in Bacteroides distasonis.
abstract: In this study we investigated the presence of the cfxA gene (encoding a class A beta-lactamase) in 73 strains of the Bacteroides fragilis group belonging to the species B. distasonis (34), B. vulgatus (14), B. thetaiotaomicron (8), B. merdae (6), B. caccae (9) and B. ovatus (2) isolated from human intestinal microflora of healthy children and adults. Employing specific primers to the cfxA gene, a 312-bp amplified fragment was obtained in 2 strains of B. vulgatus and 9 strains, the majority from children, of B. distasonis. The expression of this enzyme was analysed by determining the MICs to cefoxitin and cefotaxime and values varied from 2 to >256 microg/ml of both cefoxitin and cefotaxime. Sequence analysis of the amplicons corresponding to the cfxA gene from B. distasonis and B. vulgatus revealed identical sequences between these isolates and high similarity with other beta-lactamase genes of anaerobes such as cfxA of B. vulgatus (99%) and cfxA2 of Prevotella intermedia (99%), both sequences of which deposited in Genbank under accession numbers U38243 and AF118110, respectively. However, a fragment obtained from a B. distasonis strain (EC17-4) showed a unique RFLP profile and 87% nucleotide similarity with cfxA and cfxA2 genes. These results seem to suggest a dissemination of these resistance determinants among Bacteroides species.
authors.affiliation: Instituto de Microbiologia Prof. Paulo de Góes, CCS, Bloco I, UFRJ Universidade Federal do Rio de Janeiro, Ilha do Fundão, RJ, CEP: 21941-590, Rio de Janeiro, Brazil.
authors.forename: Kátia Eliane Santos
authors.initials: KE
authors.lastname: Avelar
authors.forename: Koko
authors.initials: K
authors.lastname: Otsuki
authors.forename: Ana Carolina Paulo
authors.initials: AC
authors.lastname: Vicente
authors.forename: Jessica Manya Bittencourt Dias
authors.initials: JM
authors.lastname: Vieira
authors.forename: Geraldo Renato
authors.initials: GR
authors.lastname: de Paula
authors.forename: Regina Maria Cavalcanti Pilotto
authors.initials: RM
authors.lastname: Domingues
authors.forename: Maria Candida de Souza
authors.initials: MC
authors.lastname: Ferreira
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001439:Bacteroides / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D001483:Base Sequence; D002439:Cefotaxime / Q000494:pharmacology; D002440:Cefoxitin / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D003106:Colon / Q000382:microbiology; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D006801:Humans; D007223:Infant; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D018720:Prevotella / Q000201:enzymology / Q000235:genetics; D016415:Sequence Alignment; D017385:Sequence Homology; D013045:Species Specificity; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D002440:Cefoxitin; C462979:cfxA protein, Prevotella; D001618:beta-Lactamases; D002439:Cefotaxime