title: Plasmid-related beta-lactamase production in Bacteroides fragilis strains.
abstract: Twenty Bacteroides fragilis group species isolated from children with and without diarrhea were analyzed. Antibiotic susceptibility was performed using an agar dilution method; beta-lactamase production was determined using a nitrocefin method, and plasmids were extracted using a commercial Miniprep System. MIC values ranged from 16 to 256 microg/ml for penicillin, 4-128 microg/ml for amoxicillin/clavulanic acid, 0.25-256 microg/ml for clindamycin, and 16-256 microg/ml for penicillin. beta-Lactamase was detected in all isolates. Only five isolates harbored plasmids varying from 7.8 to 1.8 kb. Loss of 6.4- and 3.8-kb plasmids in B. fragilis C68c was related to antibiotic resistance. Low molecular weight plasmids of 2.8-1.8 kb were stable. PCR amplification of cfiA and cepA genes was observed using total DNA, and the cfiA gene was also amplified from the 6.4-kb plasmid.
authors.affiliation: Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1374, São Paulo, 05508-900 SP, Brazil.
authors.forename: Viviane
authors.initials: V
authors.lastname: Nakano
authors.forename: Gabriel
authors.initials: G
authors.lastname: Padilla
authors.forename: Marilis
authors.initials: M
authors.lastname: do Valle Marques
authors.forename: Mario Julio
authors.initials: MJ
authors.lastname: Avila-Campos
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics; D001442:Bacteroides Infections / Q000382:microbiology; D001441:Bacteroides fragilis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D002648:Child; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D003967:Diarrhea / Q000382:microbiology; D024881:Drug Resistance, Bacterial / Q000235:genetics; D006801:Humans; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D001618:beta-Lactamases; C063912:carbapenemase