192. Timely Identification of the Emerging Zoonotic Enteric Pathogen Arcobacter: Thank Heaven for MALDI?
Session: Poster Abstract Session: Diagnostics: Bacteriology, Sequencing, and Resistance
Thursday, October 27, 2016
Room: Poster Hall
Posters
  • 20161027_IDweek_poster 192.png (373.5 kB)
  • Background: Arcobacter belong to the family Campylobacteraceae and are considered emerging zoonotic enteric pathogens. Identification and differentiation from other family members is hampered when using routine biochemical tests. Molecular methods are more reliable but time consuming and due to the fast growing number of well characterized novel Arcobacter spp, a combination of techniques is warranted to avoid unreliable results or misidentifications. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a fast and robust technique that has recently revolutionized microbial identification in clinical microbiology. We assessed the ability of MALDI-TOF MS to identify Arcobacter spp. of human interest and validated the impact of enlarging the spectrum database on the quality of identification

    Methods: The in vitro diagnostic spectrum database (IVD) of MALDI-TOF MS (Bruker, Bremen, Germany) was compared to an in house reference spectrum library (NEW) containing a more representative set (n=63) of Arcobacter spp. strains of zoonotic interest. A challenge panel (n=205) of human and veterinary clinical strains of Campylobacteraceae and reference strains of recently described environment-related Arcobacterspp. were included to test specificity.

    Results: The sensitivity of NEW was significantly better than IVD for A. butzleri and A. cryaerophilus identification (100% and 94% versus 74% and 15%). For A. skirrowii, sensitivity remained low (21 versus 0%). Implementation of a short extraction protocol augmented sensitivity for this species to 64%. Specificity of NEW remained excellent without any misidentifications of human clinical strains of Arcobacter spp or Campylobacter fetus, C. jejuni and C.coli. Dendrogram clustering and best matches ranking was used to reduce the size of the NEW database for use in clinical practice.

    Conclusion: The use of an enriched database for MALDI-TOF MS identification of Arcobacter spp of human interest produced high-confidence identifications to species level resulting in a significantly improved sensitivity with conservation of excellent specificity. Misidentifications, which can have therapeutic and public health consequences, were not encountered.

    Anne-Marie Van Den Abeele, MD1, Dirk Vogelaers, MD, PhD2, Ivo Cox, MLT1, Cindy Germis, MLT1, Annick Van Der Straeten, MLT1, Peter Vandamme, PhD3 and Kurt Houf, DVM, PhD4, (1)Microbiology Laboratory, St-Lucas Hospital, Ghent, Belgium, (2)General Internal Medicine, Ghent University Hospital, Ghent, Belgium, (3)Biochemistry, Physiology and Microbiology, Faculty of SciencesGhent University, Ghent, Belgium, (4)Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine Ghent University, Merelbeke, Belgium

    Disclosures:

    A. M. Van Den Abeele, None

    D. Vogelaers, None

    I. Cox, None

    C. Germis, None

    A. Van Der Straeten, None

    P. Vandamme, None

    K. Houf, None

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