title: Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry for the identification of Neisseria gonorrhoeae.
abstract: 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 NH-examination 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.
authors.affiliation: Division of Infection, Barts Health NHS Trust, London, UK. Electronic address: ruaridh.buchanan@nhs.net.
authors.forename: R
authors.initials: R
authors.lastname: Buchanan
authors.affiliation: Division of Infection, Barts Health NHS Trust, London, UK.
authors.forename: D
authors.initials: D
authors.lastname: Ball
authors.affiliation: Division of Infection, Barts Health NHS Trust, London, UK.
authors.forename: H
authors.initials: H
authors.lastname: Dolphin
authors.affiliation: Division of Infection, Barts Health NHS Trust, London, UK; Public Health England, London, UK.
authors.forename: J
authors.initials: J
authors.lastname: Dave
mesh_terms: D006069:Gonorrhea / Q000175:diagnosis / Q000382:microbiology; D006801:Humans; D058889:Molecular Typing; D009344:Neisseria gonorrhoeae / Q000145:classification*; D012680:Sensitivity and Specificity; D015231:Sexually Transmitted Diseases, Bacterial / Q000175:diagnosis / Q000382:microbiology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods
keywords: API NH; Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry; Neisseria gonorrhoeae; Pathogen identification; Sexually transmitted infection