Homology analysis of Carbapenems-resistant klebsiella pneumoniae by MALDI-TOF MS

Abstract

Objective To evaluate the ability of matrix-assisted laser desorption/ionization-time of flight mass spectrometry(MALDI-TOF MS) in the homology analysis of Carbapenems-resistant klebsiella pneumonia. Methods Twenty-one non-duplicated strains of Carbapenems-resistant klebsiella pneumoniae were isolated from Shandong Provincial Hospital affiliated to Shandong University during April 2011 and October 2013 in this study. Twenty isolates were from neonatal unit and one from cardiac surgery. The homology analysis of Carbapenems-resistant klebsiella pneumoniae was performed with pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and MALDI-TOF MS respectively. Results The result of PFGE was consistent with MLST. The twenty-one CRKPN strains were divided into three groups by MALDI-TOF MS according to their relationship, 18 of them belonged to II group, and the homology was higher than 75%. From the analysis of protein mass spectra of 18 strains, the protein peaks were roughly the same. Thus, it was concluded that their relationship was close, and the results were basically consistent with the results of PFGE and MLST. The H13 strain with low homology (<60%) was different from the above strains, especially in the molecular weight 4365, 5381 and 6289.The PFGE analysis showed that the homology between H13 and other strains was 61%, and the MLST classification result was ST54. Conclusions MALDI-TOF MS can be used to identify CRKPN accurately and analyze its homology analysis more conveniently than other methods in clinical laboratory. MALDI-TOF MS has the potential to be used as an easy and rapid epidemiology typing tool for nosocomial infection investigation caused by drug-resistant bacteria.(Chin J Lab Med, 2018, 41: 589-595) Key words: Klebsiella pneumoniae; Carbapenems; Drug resistance, bacterial; Sequence homology; Spectrometry, mass, matrix-assisted laser desorption-ionization