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Class 1 integrons in drug-resistant E. coli and K. pneumoniae from blood stream infections
Adriana Hristea, Mihaela Ion, Daniela Maxim, Leontina Banică, Maria Nica, Mariana Buzea, Ioana Bădicuţ, Mona Popoiu, Cristina Ţenea, Adrian Streinu-Cercel, Ioana Diana Olaru
Abstract: Objective. The aims of our study were to assess the presence of class 1 integrons in drug-resistant E. coli and K. pneumoniae from blood stream infections (BSI) and to analyze their association with epidemiological and clinical characteristics. Methods We retrospectively studied BSI, classified as community-acquired (CA), health care associated (HCA), and hospital-acquired (HA), caused by antibiotic-resistant E. coli and K. pneumoniae strains from patients admitted to three hospitals in Bucharest between January 2009 and May 2011. Patient characteristics were also collected and analyzed. The susceptibility testing was performed with disk-diffusion and automated methods. Integrons were detected by PCR targeting the integrase gene. Results. Three hundred and twenty-five Gram negative BSI isolates were identified. Of these, the most common species were 163 E. coli (50%), and 67 K. pneumoniae (20%). Class I integrons were identified in 42 of 77 drug-resistant E. coli and 18 of 26 K. pneumoniae drug-resistant isolates. The presence of integrons in E. coli and K. pneumoniae BSI isolates was significantly associated with trimethoprim-sulfamethoxazole resistance (p<0.01 respectively 0.01). Integron-positive isolates were also more likely to be multi-resistant. The int1 gene was detected among 17 (50%) CA, 17 (59%) HCA and 24 (67%) HA infections. Conclusion. The proportions of drug resistance in class 1 integron-positive strains were higher than in those not carrying integrons, for both E. coli and K. pneumoniae. Integrons were significantly associated with trimethoprim-sulfamethoxazole resistance. Most of resistant E. coli and K. pneumoniae isolated either in CA, HCA or HA bacteremias are carrying class 1 integrons, which are easily transferable.
Keywords: class 1 integrons,bacteremia,E. coli,K. pneumoniae
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Hristea A, Ion M, Maxim D, Banică L, Nica M, Buzea M, et al. Class 1 integrons in drug-resistant E. coli and K. pneumoniae from blood stream infections. Rev Romana Med Lab. 2012;20(3):279-86
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