Detection of carbapenem-producing Enterobacteriaceae by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) / 中华微生物学和免疫学杂志

ABSTRACT

Objective To evaluate the value of matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) in detecting carbapenemases-producing Enterobacteriaceae. Methods Sixty-one carbapenemase-producing Enterobacteriaceae (CPE) and 108 carbapenemase-none-producing Enterobacteriaceae(NCPE) strains that isolated in the Renmin Hospital of Wuhan University from February 2016 to February 2017 were used in this study. Twenty CPE strains and 20 NCPE strains were se-lected and used to establish the optimum reaction system of MALDI-TOF MS for the detection of carbapene-mase-producing Enterobacteriaceae strains. Results The optimal reaction system of MALDI-TOF MS was successfully established:equal volumes of imipenem solution (1 mg/ml) and bacterial suspension (2 Mc-Farland turbidity standard) were first mixed together and incubated at 37℃ for 20 min,and then the super-natant was detected by MALDI-TOF MS after centrifugating. It would be a carbapenemase-producing strain if the peak of (300±0.55) m/z in the mass spectrum of imipenem disappeared completely. MALDI-TOF MS was used to identify carbapenemase-producing Enterobacteriaceae strains among the 169 strains and the result was consistant with that by using carbapenemase gene detection. Conclusion MALDI-TOF MS could accu-rately and rapidly detect carbapenemases-producing Enterobacteriaceae. It could be used as a routine method to provide references for early anti-infective treatment and infection control in hospitals.