Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry for the identification of Neisseria gonorrhoeae

Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) was compared with the API NH biochemical method for the identification of Neisseria gonorrhoeae in routine clinical samples. A retrospective review of laboratory records for 1090 isolates for which both biochemical and MALDI-TOF MS identifications were available was performed. Cases of discrepant results were examined in detail for evidence supportive of a particular organism identification. Of 1090 isolates, 1082 were identified as N. gonorrhoeae by API NH. MALDI-TOF MS successfully identified 984 (91%) of these after one analysis, rising to 1081 (99.9%) after two analyses, with a positive predictive value of 99.3%. For those isolates requiring a repeat analysis, failure to generate an identifiable proteomic signature was the reason in 76% of cases, with alternative initial identifications accounting for the remaining 24%. MALDI-TOF MS identified eight isolates as N. gonorrhoeae that were not identified as such by API NHdexamination of these discrepant results suggested that the MALDI-TOF MS identification may be the more reliable. MALDI-TOF MS is at least as accurate and reliable a method of identifying N. gonorrhoeae as API NH. We propose that MALDI-TOF MS could potentially be used as a single method for N. gonorrhoeae identification in routine cases by laboratories with access to this technology. (C) 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.