title: Matrix-assisted laser desorption ionisation time-of-flight mass spectrometry rapid detection of carbapenamase activity inAcinetobacter baumanniiisolates.
abstract: BACKGROUND
  Carbapenamase-producing Acinetobacter baumannii are an increasing threat in hospitals and Intensive Care Units. Accurate and rapid detection of carbapenamase producers has a great impact on patient improvement and aids in implementation of infection control measures.
  
  
  OBJECTIVE
  In this study, we describe the use of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI TOF MS) to identify carbapenamase-producing A. baumannii isolates in up to 3 h. Isolates and Methods: A total of 50 A. baumannii isolates (of which 39 were carabapenamase producers) were tested using MALDI TOF MS. Isolates were incubated for 3 h with 0.25 mg/ml up to 2 mg/ml of imipenem (IMP) at 37°C. Supernatants were analysed by MALDI TOF to analyse peaks corresponding to IMP (300 Da) and an IMP metabolite (254 Da) using UltrafleXtreme (Bruker Daltonics, Bremen, Germany).
  
  
  RESULTS
  All carbapenamase-producing isolates were evidenced by the disappearance or reduction in intensity of the 300 Da peak of IPM and the appearance of a 254 Da peak of the IPM metabolite. In isolates that did not produce carbapenamase, the IPM 300 Da peak remained intact.
  
  
  CONCLUSIONS
  MALDI TOF is a promising tool in the field of diagnostic microbiology that has the ability to transfer identification and antimicrobial susceptibility testing time from days to hours.
authors.affiliation: Department of Medical Microbiology and Immunology, Faculty of Medicine, Alexandria University, Alexandria, Egypt.
authors.forename: Noha
authors.initials: N
authors.lastname: Abouseada
authors.affiliation: Department of Medical Microbiology and Immunology, Faculty of Medicine, Alexandria University, Alexandria, Egypt.
authors.forename: May
authors.initials: M
authors.lastname: Raouf
authors.affiliation: Department of Chemical Pathology, High Institute of Research, Alexandria University, Alexandria, Egypt.
authors.forename: Eman
authors.initials: E
authors.lastname: El-Attar
authors.affiliation: Department of Clinical Pathology, Faculty of Medicine, Alexandria University, Alexandria, Egypt.
authors.forename: Pacinte
authors.initials: P
authors.lastname: Moez
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects / Q000201:enzymology*; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D001426:Bacterial Proteins / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D015378:Imipenem / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D008970:Molecular Weight; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013696:Temperature; D013997:Time Factors; D001618:beta-Lactamases / Q000032:analysis* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015378:Imipenem; D001618:beta-Lactamases; C063912:carbapenemase