288. Bruker MALDI-TOF Identification of Coagulase Negative Staphylococci
Session: Poster Abstract Session: Diagnostic Microbiology; Novel Molecular Methods
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
  • CNS poster IDweek 2013 Final_1PDF.pdf (199.0 kB)
  • Background:

    Coagulase-negative staphylococci (CNS) historically-considered to be commensals or contaminants are now recognized to be pathogens associated with infections of foreign bodies and a major cause of line associated bacteremia. The identification of CNS like S. lugdunensisis important to ensure the correct interpretation of susceptibility results.


    Four hundred and eighty five CNS were randomly selected from a bank of CNS previously identified to species level by long tube biochemicals. The CNS were  identified by the Bruker MALDI-TOF biotyper and results were compared to the biochemical identification. The following CNS were identified by the Direct Plate Formic Acid (70%) Extraction Method: S. capititis subspecies ureolyticus (n=50),S. caprae subspecies caprae (n=50), S. captitis subspecies capitis (n=50), S. cohnii (n=49), S. epidermidis (n=90), S. haemolyticus (n=25), S. hominis (n=17), S. intermedius (n=7), S. lugdunensis (n=15), S. saprophyticus (n=25), S. schleiferi (n=22), S. simulans (n=24), S. warneri (n=24) and S. xylosus (n=27). The following American Type Culture Collection (ATCC) strains were used for quality control: Staphylococcus cohnii ATCC 29974, S. epidermidis ATCC 14990, S. haemolyticus ATCC 29970, S. hominis ATCC 27845, S. intermedius ATCC 29663, S. saprophyticus ATCC 15305, S. wameri ATCC 27836, and S.xylosus ATCC 29971.


    The Bruker MALDI-TOF identified all of the CNS correctly to the subspecies level with the exception of S.capitis subspecies urealyticus, where 48 were identified as S.capitis subspecies capitis and one S.saprophyticus which was identified as S. xylosus. The identification were correct to the species level in  484 of the 485 CNS (99,7%) and to the subspecies level in 436 of 485 CNS (89,9%).

    Conclusion: The Bruker MALDI-TOF is excellent at identifying the Coagualase negative Staphylococci to the species level.

    Johan Delport, MD, Microbiology Department, London Health Sciences, London, ON, Canada


    J. Delport, None

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