Resumo

Carbapenems are the drugs of choice for serious infections caused by ESBL- and/or high-level AmpC – producing enterobacteria. However, in recent years, several studies have shown carbapenemase–mediated resistance to carbapenems. KPC carbabapenemase has been found worldwide, commonly produced by isolates of Klebsiella pneumoniae. In this work, we describe the detection of bla_KPC gene in 15 clinical isolates of K. pneumoniae from four hospitals in Recife, Brazil. Bacterial isolates were collected between February-May 2010 and submitted to automated identification (Vitek, Biomerieux). Antimicrobial susceptibility was determined by disk diffusion method, according to CLSI (2010). Carbapenemase production was investigated by the modified Hodge test and confirmed by specific PCR for the gene bla_KPC. Plasmid extraction was performed following the Kieser method. Susceptibility results showed that over 90% of the isolates were resistant to third generation cephalosporins, amikacin, cephalotin and aztreonam. Only 12.5% were resistant to meropenem and imipenem. On the other hand, all the isolates were resistant to ertapenem. bla_KPC gene was detected in 93.7% (15/16) of the isolates. These results pointed out for the high occurrence of KPC enzymes in isolates in vitro susceptible to imipenem and meropenem. Moreover, KPC producing- K. pneumoniae showed to be disseminated in each of the four hospitals studied. Plasmid analysis demonstrated the isolates had different seven plasmid profiles, with plasmid sizes ranging from 6.73kb to 168kb. Further studies will be performed on order to characterize the plasmids and determine the clonal variability of the isolates. Our results indicate that KPC-producing bacteria are emerging in multiple institutions in Recife, most of them apparently susceptible to carbapenems, representing a big therapeutic challenge.