Non-molecular detection of carbapenemases in Enterobacteriaceae clinical isolates.

Infections caused by carbapenemase-producing bacteria are becoming a major clinical and public health concern. Detection of carbapenemase producing strains is often challenging, since susceptibility to carbapenems may vary significantly among carbapenemase producers. Some carbapenemases have shown to exhibit weak activity against carbapenems leading to minimum inhibitory concentrations of carbapenems below the breakpoint for defining clinical resistance and even below the proposed screening breakpoint. Thus, reliable and rapid detection of carbapenemase-activity is needed for an appropriate patient management and a rapid implementation of infection prevention and control measures. Over the last years, an increasing number of non-molecular assays for prompt detection of carbapenemase activity have been described and developed. However, none of the currently available phenotypic methods have proved to be full specific and sensitive. Selection of the appropriate methodological approach will depend on each situation. Factors to be considered include the epidemiological status, laboratory resources and availability of other confirmation tests. In this review, we provide an overview of the currently available non-molecular methods for detection of carbapenemase activity.