Carbapenemases among Klebsiella pneumoniae: sensitivity, E-test and Hodge test

Carbapenems are the major weapons in the treatment of nosocomial infections. Since 1996, there have been an emergence and dissemination of carbapenem resistance in the world, especially among Enterobacteriaceae. Resistance is due to one or several mechanisms including production of carbapenemases. A prospective study was carried out from April to September 2011 at the Laboratory of Microbiology of Military Teaching Hospital in Rabat. The aim of this study was to search by phenotypic methods carbapenemases production in Klebsiella pneumoniae at Laboratory of Microbiology of the HMIMV of Rabat by disc diffusion for susceptibility to imipenem (IMP) and ertapenem (ETP), E-test and Hodge test; 211 strains of K. pneumoniae were analyzed. The samples were most frequently obtained from the urinary tract (63.8%); pus (16.5%) and blood cultures (11.8%); 27% of the strains produced extended spectrum of beta-lactamase (ESBL); 3 strains were resistant to ertapenem by disc diffusion. Investigations of these 3 strains in E-test shown that they were resistant to ertapenem but susceptible to imipenem. Tested by Hodge method, 3 strains gave repeatedly positive results. Thus, rate of K. pneumoniae producing KPC type in our study is 1.42%. Our study shows the evidence of K. pneumoniae type carbapenemase (KPC) in Military Teaching Hospital of Rabat. However, the gene encoding the type of resistance must be determined by molecular methods.