Emergence Of Qnrb10 Associated Complex Class 1 Integrons Among Clinical Citrobacter And Enterobacter Isolates From Argentina

QUIROGA MARÍA PAULA; MERKIER ANDREA KARINA; CENTRÓN DANIELA

Salvador. Brazil.

Jornada; III Seminário de Resistência Bacteriana, II Seminário de Resistência Microbiana; 2008

Sociedade Brasielira de Microbiología

Introduction: Enterobacter and Citrobacter spp. are nosocomial pathogens with multiple resistance mechanisms to diverse families of antibiotics. Integrons are genetic elements that contain the components of a site-specific recombination system that recognizes and captures mobile gene cassettes. Class 1 integrons are the most frequently found in clinical isolates and they shows different rearrangements including gene cassettes which codifies for resistance mechanisms to almost all the families of antibiotics. Complex class 1 (CC1) integrons also contain a site specific recombinase which is capable of mobilize antibiotic resistance genes. Objectives: The aim of this study was to evaluate the dispersion and characterization of class 1 and CC1 integrons among 30 Enterobacter and Citrobacter spp. multiresistant clinical isolates from 7 hospitals from Buenos Aires. Methods: Total DNA was extracted, subjected to PCR amplifications for the intI1 and orf513 genes and PCR cartography in order of characterize the class 1 and CC1 integrons. Results: We found a high prevalence of class 1 and CC1 integrons in both genus. Among the CC1 integrons, we found different genetic structures downstream of orf513. We found a novel rearrangement containing the new allele qnrB10, this was the first report of this gene in Argentinean isolates.Conclusion: Our study shows the emergence in Argentina of a new CC1 integron containing the quinolone resistance gene qnrB10 and the clear diminution of the the blaCTX-M-2 containing integron, during the past few years. This change seems to be in response to the modification of the antibiotic therapies in the clinical settings.