Isolamento e identificação molecular do gene blaKPC-2 em Serratia marcescens

Abstract

Enterobacteria of the genus Serratia have been associated with a number of nosocomial infections, mainly in urinary and respiratory tract. Strains of Serratia sp. were identified with enzymes of carbapenemases, especially Klebsiella pneumoniae carbapenemase (KPC) type. This enzyme confers resistance to carbapenem antibiotics. KPC genes are located on mobile genetic structures, that allows its easy spreading among bacteria from the same and other species. This study aimed to identify strains of Serratia marcescens producing KPC carbapenemase type, that were isolated from patients admitted into a teaching hospital in Dourados/MS. The strains were collected during October 2011 to May 2012. They were identified by the automated system Vitek®2 (BioMérieux). The strains which were resistant to carbapenems, were subjected to the modified Hodge test. The sensitivity to carbapenems was evaluated by using minimum inhibitory concentration (MIC). The presence of blaKPC-2 gene was measured by the technique of Polymerase Chain Reaction (PCR). In this study, it was identified 27 strains of S. marcescens, from tracheal aspirates, urine culture, blood culture, rectal swab, nasal swab, eschar and catheter. In these strains, 96.29% were positive in the modified Hodge test, being considered possibly producing carbapenemases. In the MIC determination, 100% of strains were resistant to imipenem (>2 µg/mL) and ertapenem (>4 µg/mL) antibiotics and 92.6% were resistant to meroponem (>4 µg/mL). In the total of 27 strains, 24 (88,88%) were positive by PCR for blaKPC-2 gene. These data demonstrate a high prevalence of strains of S. marcescens producing KPC in a teaching hospital in Dourados/MS. It is believed that these results will contribute to preventive actions in the control of nosocomial infections caused by multiresistant microorganisms of clinical interest.