title: An evaluation of matrix-assisted laser desorption ionization time-of-flight mass spectrometry for the identification of Staphylococcus pseudintermedius isolates from canine infections.
abstract: It has been proposed, based on taxonomic and molecular studies, that all canine isolates belonging to Staphylococcus intermedius group (SIG) should be renamed Staphylococcus pseudintermedius. However, isolates of SIG and other coagulase-positive staphylococci share many phenotypic characteristics, which could lead to misidentification. The accuracy of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identifying S. pseudintermedius isolates obtained from canine infections was evaluated, using a polymerase chain reaction (PCR)-based identification as the gold standard. In addition, MALDI-TOF MS was compared with conventional biochemical tests. A central problem was the incorrect identification of S. pseudintermedius isolates as S. intermedius by either MALDI-TOF MS or biochemical identification. From the 49 S. pseudintermedius isolates identified by the molecular method, only 21 could be assigned to this species by the biochemical approach and only 12 by MALDI-TOF MS. The 6 S. aureus isolates were correctly identified by all 3 techniques. However, using biochemical tests, 9 S. pseudintermedius were mistakenly classified as S. aureus, indicating a reduced specificity relative to the MALDI-TOF MS system. Analysis with the MALDI-TOF MS platform allowed rapid and accurate identification of the 49 isolates to the S. intermedius group but the approach was very limited in identifying S. pseudintermedius isolates, as only 12 of 49 isolates were correctly identified, a sensitivity of 0.24 (95% confidence interval: 0.13-0.39).
authors: Laboratory of Animal Health, Infectious Disease Department, Science Centre and Agricultural Technologies, State University of Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro State, Brazil (Silva, Garcia, Vieira-da-Motta)The Laboratory of Bacterial Molecular Biology, Microbiology Department, Institute of Microbiology Paulo de Góes, Health Science Centre, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro State, Brazil (Ferreira, Silva-Carvalho, Botelho, Figueiredo).
authors: Marcella Braga
authors: MB
authors: Silva
authors: Laboratory of Animal Health, Infectious Disease Department, Science Centre and Agricultural Technologies, State University of Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro State, Brazil (Silva, Garcia, Vieira-da-Motta)The Laboratory of Bacterial Molecular Biology, Microbiology Department, Institute of Microbiology Paulo de Góes, Health Science Centre, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro State, Brazil (Ferreira, Silva-Carvalho, Botelho, Figueiredo).
authors: Fabienne Antunes
authors: FA
authors: Ferreira
authors: Laboratory of Animal Health, Infectious Disease Department, Science Centre and Agricultural Technologies, State University of Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro State, Brazil (Silva, Garcia, Vieira-da-Motta)The Laboratory of Bacterial Molecular Biology, Microbiology Department, Institute of Microbiology Paulo de Góes, Health Science Centre, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro State, Brazil (Ferreira, Silva-Carvalho, Botelho, Figueiredo).
authors: Luize Neli Nunes
authors: LN
authors: Garcia
authors: Laboratory of Animal Health, Infectious Disease Department, Science Centre and Agricultural Technologies, State University of Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro State, Brazil (Silva, Garcia, Vieira-da-Motta)The Laboratory of Bacterial Molecular Biology, Microbiology Department, Institute of Microbiology Paulo de Góes, Health Science Centre, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro State, Brazil (Ferreira, Silva-Carvalho, Botelho, Figueiredo).
authors: Maria Cícera
authors: MC
authors: Silva-Carvalho
authors: Laboratory of Animal Health, Infectious Disease Department, Science Centre and Agricultural Technologies, State University of Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro State, Brazil (Silva, Garcia, Vieira-da-Motta)The Laboratory of Bacterial Molecular Biology, Microbiology Department, Institute of Microbiology Paulo de Góes, Health Science Centre, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro State, Brazil (Ferreira, Silva-Carvalho, Botelho, Figueiredo).
authors: Larissa Alvarenga Batista
authors: LA
authors: Botelho
authors: Laboratory of Animal Health, Infectious Disease Department, Science Centre and Agricultural Technologies, State University of Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro State, Brazil (Silva, Garcia, Vieira-da-Motta)The Laboratory of Bacterial Molecular Biology, Microbiology Department, Institute of Microbiology Paulo de Góes, Health Science Centre, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro State, Brazil (Ferreira, Silva-Carvalho, Botelho, Figueiredo) agnes@micro.ufrj.br.
authors: Agnes Marie Sá
authors: AM
authors: Figueiredo
authors: Laboratory of Animal Health, Infectious Disease Department, Science Centre and Agricultural Technologies, State University of Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro State, Brazil (Silva, Garcia, Vieira-da-Motta)The Laboratory of Bacterial Molecular Biology, Microbiology Department, Institute of Microbiology Paulo de Góes, Health Science Centre, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro State, Brazil (Ferreira, Silva-Carvalho, Botelho, Figueiredo).
authors: Olney
authors: O
authors: Vieira-da-Motta
mesh_terms: D000818:Animals; D004269:DNA, Bacterial / Q000032:analysis; D004283:Dog Diseases / Q000175:diagnosis* / Q000382:microbiology; D004285:Dogs; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000662:veterinary; D013203:Staphylococcal Infections / Q000175:diagnosis / Q000662:veterinary*; D057789:Staphylococcus intermedius / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D004269:DNA, Bacterial
keywords: Matrix-assisted laser desorption ionization time-of-flight mass spectrometry; Staphylococcus intermedius group; Staphylococcus pseudintermedius