title: Antibiotic resistance genes in anaerobic bacteria isolated from primary dental root canal infections.
abstract: Fourty-one bacterial strains isolated from infected dental root canals and identified by 16S rRNA gene sequence were screened for the presence of 14 genes encoding resistance to beta-lactams, tetracycline and macrolides. Thirteen isolates (32%) were positive for at least one of the target antibiotic resistance genes. These strains carrying at least one antibiotic resistance gene belonged to 11 of the 26 (42%) infected root canals sampled. Two of these positive cases had two strains carrying resistance genes. Six out of 7 Fusobacterium strains harbored at least one of the target resistance genes. One Dialister invisus strain was positive for 3 resistance genes, and 4 other strains carried two of the target genes. Of the 6 antibiotic resistance genes detected in root canal strains, the most prevalent were blaTEM (17% of the strains), tetW (10%), and ermC (10%). Some as-yet-uncharacterized Fusobacterium and Prevotella isolates were positive for blaTEM, cfxA and tetM. Findings demonstrated that an unexpectedly large proportion of dental root canal isolates, including as-yet-uncharacterized strains previously regarded as uncultivated phylotypes, can carry antibiotic resistance genes.
authors.affiliation: Department of Endodontics and Molecular Microbiology Laboratory, Faculty of Dentistry, Estácio de Sá University, Rua Alfredo Baltazar da Silveira, 580/cobertura, Recreio, Rio de Janeiro 22790-710, RJ, Brazil.
authors.forename: Isabela N
authors.initials: IN
authors.lastname: Rôças
authors.forename: José F
authors.initials: JF
authors.lastname: Siqueira
mesh_terms: D001421:Bacteria, Anaerobic / Q000235:genetics* / Q000302:isolation & purification*; D001424:Bacterial Infections / Q000382:microbiology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D003786:Dental Pulp Cavity / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D011671:Pulpitis / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S