title: In vitro effect of antibiotics on biofilm formation by Bacteroides fragilis group strains isolated from intestinal microbiota of dogs and their antimicrobial susceptibility.
abstract: The Bacteroides fragilis group strains colonize the intestinal tract of dogs as commensal bacteria. Nevertheless, they can be opportunistic pathogens responsible for significant morbidity and mortality rates in dogs, like in oral infections, abscesses and wound infections. The purpose of this study was to evaluate antimicrobial susceptibility in B. fragilis strains isolated from dogs intestinal microbiota and to evaluate the effect of subinhibitory concentrations of some antimicrobials on biofilm formation. A total of 30 B. fragilis group strains were tested for susceptibility to ten antimicrobial agents by broth microdilution method. Thirteen B. fragilis strains were tested for biofilm formation and the biofilm producer strains were chosen to evaluate the effect of subinhibitory concentrations of six antimicrobials on biofilm formation. The isolates were susceptible to amoxicillin-clavulanic acid, metronidazole, imipenem and chloramphenicol. Tetracycline and clindamycin were active against 50% and 33% of the strains, respectively. When biofilm-forming strains were grown in the presence of sub-MICs of imipenem and metronidazole, the inhibition of biofilm formation was observed. In contrast, enrofloxacin at ½ MIC caused a significant increase in biofilm formation in two of four strains examined. In conclusion, the B. fragilis group strains isolated were susceptible to most of the antimicrobials tested and the sub-MIC concentrations of imipenem, metronidazole and clindamycin were able to inhibit the biofilm formation.
authors.affiliation: Centro de Biomedicina, Programa de Pós Graduação em Microbiologia Medica, Laboratório de Bacteriologia, Universidade Federal do Ceará, Fortaleza, CE, Brazil. Electronic address: janice.o.silva@gmail.com.
authors.forename: Janice Oliveira
authors.initials: JO
authors.lastname: Silva
authors.affiliation: Centro de Biomedicina, Programa de Pós Graduação em Microbiologia Medica, Laboratório de Bacteriologia, Universidade Federal do Ceará, Fortaleza, CE, Brazil.
authors.forename: Ana Catarina
authors.initials: AC
authors.lastname: Martins Reis
authors.affiliation: Laboratorio de Investigación en Bacteriología Anaerobia, Facultad de Microbiología and Centro de Investigación en Enfermedades Tropicales, Universidad de Costa Rica, San José, Costa Rica.
authors.forename: Carlos
authors.initials: C
authors.lastname: Quesada-Gómez
authors.affiliation: Faculdade de Veterinária, Universidade Estadual do Ceará, Fortaleza, CE, Brazil.
authors.forename: Adriana Queiroz
authors.initials: AQ
authors.lastname: Pinheiro
authors.affiliation: Núcleo De Estudos Em Microscopia E Processamento De Imagem (NEMPI), Departamento de Morfologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil.
authors.forename: Rosemary Souza
authors.initials: RS
authors.lastname: Freire
authors.affiliation: Núcleo De Estudos Em Microscopia E Processamento De Imagem (NEMPI), Departamento de Morfologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil.
authors.forename: Reinaldo Barreto
authors.initials: RB
authors.lastname: Oriá
authors.affiliation: Centro de Biomedicina, Programa de Pós Graduação em Microbiologia Medica, Laboratório de Bacteriologia, Universidade Federal do Ceará, Fortaleza, CE, Brazil.
authors.forename: Cibele Barreto Mano
authors.initials: CB
authors.lastname: de Carvalho
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001441:Bacteroides fragilis / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development*; D004285:Dogs; D041981:Gastrointestinal Tract / Q000382:microbiology; D008826:Microbial Sensitivity Tests
chemical_list: D000900:Anti-Bacterial Agents
keywords: Antimicrobials resistance; Bacteroides fragilis; Biofilm; Intestinal microbiota