First national survey of antibiotic susceptibility of the Bacteroides fragilis group: emerging resistance to carbapenems in Argentina

Authors
Fernández Canigia, Liliana; Litterio, Mirta; Legaria, María C.; Castello, Liliana; Predari, Silvia C.; Di Martino, Ana; Rossetti, Adelaida; Rollet, Raquel; Carloni, Graciela; Bianchini, Hebe; Cejas, Daniela; Radice, Marcela Alejandra; Gutkind, Gabriel Osvaldo; Anaerobe Surveillance Team
Publication Year
2012
Language
English
Format
article
Status
Published version
Description
The antibiotic susceptibility rates of 363 clinical Bacteroides fragilis group isolates collected from 17 centers in Argentina during the period from 2006 to 2009 were as follows: piperacillin-tazobactam, 99%; ampicillin-sulbactam, 92%; cefoxitin, 72%; tigecycline, 100%; moxifloxacin, 91%; and clindamycin, 52%. No metronidazole resistance was detected in these isolates during this time period. Resistance to imipenem, doripenem, and ertapenem was observed in 1.1%, 1.6%, and 2.3% of B. fragilis group strains, respectively. B. fragilis species showed a resistance profile of 1.5% to imipenem, 1.9% to doripenem, and 2.4% to ertapenem. This is the first report of carbapenem resistance in Argentina. The cfiA gene was present in 8 out of 23 isolates, all of them belonging to the B. fragilis species and displaying reduced susceptibility or resistance to carbapenems (MICs ≥ 4 μg/ml). Three out of eight cfiA-positive isolates were fully resistant to carbapenems, while 5 out of 8 isolates showed low-level resistance (MICs, 4 to 8 μg/ml). The inhibition by EDTA was a good predictor of the presence of metallo-β-lactamases in the fully resistant B. fragilis strains, but discrepant results were observed for low-level resistant isolates. B. fragilis was more susceptible to antimicrobial agents than other Bacteroides species. Bacteroides vulgatus species was the most resistant to ampicillin-sulbactam and piperacillin-tazobactam, and B. thetaiotaomicron/ovatus strains showed the highest level of resistance to carbapenems, with an unknown resistance mechanism. B. vulgatus and the uncommon non-Bacteroides fragilis species were the most resistant to moxifloxacin, showing an overall resistance rate of 15.1%.
Fil: Fernández Canigia, Liliana. Asociación Argentina de Microbiología; Argentina
Fil: Litterio, Mirta. Asociación Argentina de Microbiología; Argentina
Fil: Legaria, María C.. Asociación Argentina de Microbiología; Argentina
Fil: Castello, Liliana. Asociación Argentina de Microbiología; Argentina
Fil: Predari, Silvia C.. Asociación Argentina de Microbiología; Argentina
Fil: Di Martino, Ana. Asociación Argentina de Microbiología; Argentina
Fil: Rossetti, Adelaida. Asociación Argentina de Microbiología; Argentina
Fil: Rollet, Raquel. Asociación Argentina de Microbiología; Argentina
Fil: Carloni, Graciela. Asociación Argentina de Microbiología; Argentina
Fil: Bianchini, Hebe. Asociación Argentina de Microbiología; Argentina
Fil: Cejas, Daniela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Radice, Marcela Alejandra. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Gutkind, Gabriel Osvaldo. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Anaerobe Surveillance Team.
Subject
Bacteroides fragilis group
Emerging resistance to carbapenems
Biología Celular, Microbiología
Ciencias Biológicas
CIENCIAS NATURALES Y EXACTAS
Access level
Open access
License
https://creativecommons.org/licenses/by/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/14250