phenoTypic MeThods for deTecTion of beTa-lacTaMase- MediaTed resisTance in e. coli and Klebsiella pneuMoniae

Enterobacteriaceae are major pathogens in both hospital and community. Recently the number of MDR phenotypes (multi drug resistant) increased, with the emergence of XDR phenotypes (extremely drug resistant – susceptible only to colistin and tigecycline). It is extremely important to detect and correct the reporting mechanisms for resistance. Many clinical laboratories have problems detecting extendedspectrum beta-lactamases, class C beta-lactamases and carbapenemases. Confusion exists regarding the importance of these resistance mechanisms, optimal testing methods and appropriate reporting conventions. Failure to correctly detect these enzymes contributed to their spread and sometimes, to inappropriate use of antibiotics. Clinical laboratories need to have expertise to provide a rapid and clinically relevant antibiogram result in hospitals where these resistance mechanisms are encountered. This review aims to summarize the most important methods for detection of extended spectrum β-lactamases, class C beta-lactamases and carbapenemases. We studied recent and relevant literature retrieved from PubMed