Suitability of MALDI-TOF MS for the identification of Staphylococcus aureus and members of the Staphylococcus intermedius group (S.I.G) complex [Idoneidad del uso del MALDI-TOF MS para la identificación de Staphylococcus aureus y miembros del grupo de Staphylococcus intermedius (S.I.G.)]

  1. Alcalá, L. 46
  2. Simón, M.C. 46
  3. López-Calleja, A.I. 34
  4. Ferrer, I. 34
  5. Pereira, J. 34
  6. Ortega, C. 46
  7. Torres, C. 15
  8. Viguera, N. 34
  9. Gómez-Sanz, E. 24
  10. Revillo, M.J. 34
  11. Rezusta, A. 34
  1. 1 Centro de Investigación Biomédica de La Rioja
    info

    Centro de Investigación Biomédica de La Rioja

    Logroño, España

    ROR https://ror.org/03vfjzd38

  2. 2 Environmental Genomics and Systems Biology Research Group, Institute of Natural Resource Sciences, Zurich University of Applied Sciences (ZHAW), Wädenswil, Switzerland
  3. 3 Hospital Miguel Servet
    info

    Hospital Miguel Servet

    Zaragoza, España

    ROR https://ror.org/01r13mt55

  4. 4 Instituto de Investigación Sanitaria Aragón
    info

    Instituto de Investigación Sanitaria Aragón

    Zaragoza, España

  5. 5 Universidad de La Rioja
    info

    Universidad de La Rioja

    Logroño, España

    ROR https://ror.org/0553yr311

  6. 6 Universidad de Zaragoza
    info

    Universidad de Zaragoza

    Zaragoza, España

    ROR https://ror.org/012a91z28

Revista:
Revista Electrónica de Veterinaria

ISSN: 1695-7504

Año de publicación: 2015

Volumen: 16

Número: 1

Tipo: Artículo

Otras publicaciones en: Revista Electrónica de Veterinaria

Resumen

Although Staphyolococcus spp. are commonly isolated from humans and animals, their identification is problematic. This study assessed the suitability of MALDI-TOF MS (Biotyper 3) for their identification, comparing the results obtained by using phenotypical methods, MALDI-TOF (with and without adding formic acid) and molecular identification. A collection of 37 strains identified by conventional method as S. aureus (n= 7), S. intermedius (n=1) and S. pseudintermedius (n=29), were analyzed. The isolates belonged to ill and healthy dogs (n=27) and humans (n=10), from different biological samples. All of them were also identified by molecular methods and pure cultures were processed with a MALDI-TOF MS. The information was computed using DAG-Stat. The estimated sensitivity, specificity, efficiency and kappa statistics with a 95% confidence interval were calculated separately for the three bacterial species by taking molecular identification as the gold standard. Estafilococos from 27 dogs and their owners were identified. Only a strain of S. intermedius was found, so parameters related to it, might be considered with caution. All S. aureus were correctly identified. By using MALDI-TOF MS adding formic acid, lower sensibility and good specificity were calculated for S. pseudintermedius. In this case, almost perfect agreement between tests was obtained for S. aureus and S. pseudintermedius, respectively. When no formic acid was added, total agreement was estimated for S. aureus and substantial agreement for S. pseudintermedius. This study demonstrates the validity, the usefulness and the reliability of MALDI-TOF MS in the identification of bacterial isolates belonging to Staphylococcus spp.