title: Insufficient Discriminatory Power of Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry Dendrograms to Determine the Clonality of Multi-Drug-Resistant Acinetobacter baumannii Isolates from an Intensive Care Unit.
abstract: While pulsed-field gel electrophoresis (PFGE) is recognized as the gold standard method for clonality analysis, MALDI-TOF MS has recently been spotlighted as an alternative tool for species identification. Herein, we compared the dendrograms of multi-drug-resistant (MDR) Acinetobacter baumannii isolates by using MALDI-TOF MS with those by using PFGE. We used direct colony and protein extraction methods for MALDI-TOF MS dendrograms. The isolates with identical PFGE patterns were grouped into different branches in MALDI-TOF MS dendrograms. Among the isolates that were classified as very close isolates in MALDI-TOF MS dendrogram, PFGE band patterns visually showed complete differences. We numeralized similarity among isolates by measuring distance levels. The Spearman rank correlation coefficient values were 0.449 and 0.297 between MALDI-TOF MS dendrogram using direct colony and protein extraction method versus PFGE, respectively. This study is the first paper focusing solely on the dendrogram function of MALDI-TOF MS compared with PFGE. Although MALDI-TOF MS is a promising tool to identify species in a rapid manner, our results showed that MALDI-TOF MS dendrograms could not substitute PFGE for MDR Acinetobacter baumannii clonality analysis.
authors.affiliation: Department of Laboratory Medicine, Severance Hospital, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: John Hoon
authors.initials: JH
authors.lastname: Rim
authors.affiliation: Department of Laboratory Medicine, Hanyang University College of Medicine, Hanyang University Seoul Hospital, Seoul, Republic of Korea.
authors.forename: Yangsoon
authors.identifier: 0000-0003-1220-5372
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine, Severance Hospital, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Sung Kuk
authors.initials: SK
authors.lastname: Hong
authors.affiliation: Department of Laboratory Medicine, Severance Hospital, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Yongjung
authors.initials: Y
authors.lastname: Park
authors.affiliation: Department of Laboratory Medicine, Severance Hospital, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: MyungSook
authors.initials: M
authors.lastname: Kim
authors.affiliation: Department of Laboratory Medicine, Severance Hospital, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Roshan
authors.initials: R
authors.lastname: D'Souza
authors.affiliation: Department of Infection Control, Severance Hospital, Seoul, Republic of Korea.
authors.forename: Eun Suk
authors.initials: ES
authors.lastname: Park
authors.affiliation: Department of Laboratory Medicine, Severance Hospital, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Dongeun
authors.initials: D
authors.lastname: Yong
authors.affiliation: Department of Laboratory Medicine, Severance Hospital, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Kyungwon
authors.initials: K
authors.lastname: Lee
mesh_terms: D040981:Acinetobacter baumannii / Q000235:genetics* / Q000302:isolation & purification* / Q000472:pathogenicity; D018432:Drug Resistance, Multiple / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D006801:Humans; D007362:Intensive Care Units; D013045:Species Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization