Análise da resistência a antimicrobianos em microrganismos isolados de hemoculturas em hospitais de Niterói

Introduction: bloodstream infections are one of the most serious bacterial infections, especially if caused by resistant microorganisms. The purpose of this study was to assess the prevalence and resistance profile of pathogens isolated from blood cultures in a public and a private hospital of Niteroi, Rio de Janeiro, Brazil. Methods: a case-series of patients with blood stream infection was conducted at a 227-bed public general hospital and at a 123-bed private general hospital from August 2009 to August 2010. All isolates were consecutively detected from patients minimum age of 18 years and identified by the routine methodology used at each laboratory. Every E. coli, K. pneumoniae, K. oxytoca and P. mirabilis isolates were tested for ESBL (extended spectrum beta-lactamase) production using the CLSI guidelines. The Enterobacteriaceae was tested for carbapenemase production using the modified hodge test (CLSI). Every P. aeruginosa were tested for metallo-betalactamases (MBLs) producing by the phenotypic method of combined disk. The polymerase chain reaction (PCR) was used to detect the MβLs genes (blaIMP, blaVIM, blaSPM). The genetic similarity between the strains was evaluated in samples which were positive for MBLs using the pulsed field gel electrophoresis technique (PFGE). Results: were collected 195 samples of microorganisms isolated in blood cultures in the public hospital and 123 samples in the private hospital. The non-fermentatives were the major cause of bacteremia in the ICU of public hospital. The Enterobacteriaceae were the most prevalent in the the wards of private hospital. In the public hospital, we found strains producing ESBL and in the private hospital, strains producing carbapenemase. Forty samples of P. aeruginosa were tested for MBL producing. Thirteen strains (32,5%) were positive in phenotypic test and in PCR, every sample were positive for blaSPM-1, and only one was from the public institution and 12 of the particular hospital. No blaIMP-1 and blaVIM gene were detected. The PFGE analysis showed that all blaSPM-1 gene-carrying strains isolated in private hospital were genetically related (pulsetype A), suggesting a cross transmission between patients and health professionals. Conclusions: the characteristics of the microorganisms isolated from blood culture varied from hospital to hospital and between inpatient units, showing that local data can help with therapeutic choices and with the prevention and control of infection. Due to the impact of bloodstream infections and the presence of resistant microorganisms in the hospitals, additional studies and monitoring measures are necessary