title: Accuracy of conventional identification methods used for Enterobacteriaceae isolates in three Nigerian hospitals.
abstract: BACKGROUND
  Enterobacteriaceae are ubiquitously present in nature and can be found in the intestinal tract of humans and animals as commensal flora. Multidrug-resistant Enterobacteriaceae are increasingly reported and are a threat to public health implicating a need for accurate identification of the isolates to species level. In developing countries, identification of bacteria basically depends on conventional methods: culture and phenotypic methods that hamper the accurate identification of bacteria. In this study, matrix-assisted desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) technique was compared to conventional identification techniques.
  
  
  METHODS
  In total, 147 Enterobacteriaceae isolates were collected from March to May 2015 from three medical microbiology laboratories of hospitals in Edo state, Nigeria, after being tested according to the individual laboratories standard operating procedures. All isolates were stored at -20°C until tested centrally by MALDI-TOF MS.
  
  
  RESULTS
  One hundred and forty five (98.6%) isolates had a MALDI Biotyper best score > or =2.0, indicating a secure genus and probable species identification; and 2(1.36%) isolates had a best score <2.0 indicating probable genus identification. Isolates with best scores of > or =2.0 comprised nine genera and 10 species, respectively. A total of 57.2% and 33.1% of isolates identified had agreement between MALDI-TOF MS and conventional techniques for identification at genus and species level, respectively, when analyzing bacteria with MALDI Biotyper best scores > or =2.0.
  
  
  CONCLUSIONS
  The results of our study show that the applied conventional identification techniques for Enterobacteriaceae in the investigated Nigerian hospitals are not very accurate. Use of state-of-the-art identification technologies for microorganisms is necessary to guarantee comparability of bacteriological results.
authors.affiliation: Department of Pharmaceutical Microbiology, Igbinedion University Okada , Okada , Edo state , Nigeria.
authors.forename: Christiana
authors.initials: C
authors.lastname: Jesumirhewe
authors.affiliation: Department of Pharmaceutical Microbiology, Igbinedion University Okada , Okada , Edo state , Nigeria.
authors.forename: Peter Oladejo
authors.initials: PO
authors.lastname: Ogunlowo
authors.affiliation: Department of Medical Microbiology, Igbinedion Univesity Teaching Hospital , Okada , Edo state , Nigeria.
authors.forename: Mitsan
authors.initials: M
authors.lastname: Olley
authors.affiliation: Austrian Agency for Health and Food Safety (AGES), Institute of Medical Microbiology and Hygiene , Vienna , Austria.
authors.forename: Burkhard
authors.initials: B
authors.lastname: Springer
authors.affiliation: Austrian Agency for Health and Food Safety (AGES), Institute of Medical Microbiology and Hygiene , Vienna , Austria.
authors.forename: Franz
authors.initials: F
authors.lastname: Allerberger
authors.affiliation: Austrian Agency for Health and Food Safety (AGES), Institute of Medical Microbiology and Hygiene , Vienna , Austria.
authors.forename: Werner
authors.initials: W
authors.lastname: Ruppitsch
keywords: Bacterial identification; Enterobacteriaceae; MALDI-TOF MS