Performance assessment of MALDI SepsityperTM kit and serum separator tube as pretreatment methods for direct identification of microorganisms from blood cultures using MALDI-TOF mass spectrometry / 中国感染与化疗杂志

ABSTRACT

Objective The aim of this study was to evaluate the commercial SepsityperTM kit and serum separator tube coupled with matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry for direct identification of microorganisms in a blood culture system.Methods A total of 138 clinical blood samples from clinical laboratory in Renji hospital were tested with two methods respectively from April to June of 2016.Performance of the assays were compared against that of conventional bacterial culture as a reference.Results A total of 138 nonduplicate positive blood culture samples were collected,including 70 (53.03％) gram negative samples,57 (43.18％) gram positive samples,3 fungus samples,2 mixed samples,and 6 false positive samples which were excluded from further analysis.The accuracy rate of SepsityperTM kit and serum separator tube was 91.67％ and 84.09％ in rapid identification of pathogen from blood samples,83.33％ and 61.36％ in correct identification to species level.The accuracy rate of SepsityperTM kit and serum separator tube was 98.57％ and 95.71％ in identifying gram-negative bacteria,87.72％ and 78.59％ in identifying gram-positive bacteria,respectively.The turnaround time for identification of each sample was 40 min by the commercial SepsityperTM kit and 25 min by serum separator tube.Conclusions MALDI SepsityperTM kit has shown slightly higher accuracy rate in identification of pathogen from blood sample than serum separator tube,but the difference is not significant (91.67％ vs.84.09％,P＞0.05).Compared with MALDI SepsityperTM kit,serum separator tube is a rapid,easy,and cost-effective pretreatment method for direct identification of microorganisms from blood cultures using MALDI-TOF mass spectrometry.