Mycobactericidal testing of chemical germicides: Comparison of conventional culture with a reporter gene assay.

Abstract

Infections caused by members of the genus Mycobacterium , particularly Mycobacterium tuberculosis (TB), are responsible for significant morbidity and mortality worldwide. On the other hand, nontuberculous mycobacteria (NTM), which are found in the environment, are increasingly being implicated in human disease, especially in the immunocompromised. There is concern about the escalating risk of spread of M. tuberculosis and NTM through the increasing use of semi-critical medical devices such as flexible endoscopes and several cases of iatrogenic infection have already been documented in recent years. This concern is further reinforced by the realization that current methods for testing the mycobactericidal activity of high level disinfectants are slow, labor-intensive, non-quantitative and use unsuitable surrogates. Therefore, the first objective of this study was to adapt a quantitative carrier test for sporicidal activity developed in our laboratory to assess the mycobactericidal activity of chemical germicides. The second objective of this study was to develop a fluorescence assay utilizing mycobacteria expressing GFP that would reduce the turn-around time in the testing of mycobactericidal activity of germicides. (Abstract shortened by UMI.)