title: Identification of Corynebacterium spp. isolated from bovine intramammary infections by matrix-assisted laser desorption ionization-time of flight mass spectrometry.
abstract: Corynebacterium species (spp.) are among the most frequently isolated pathogens associated with subclinical mastitis in dairy cows. However, simple, fast, and reliable methods for the identification of species of the genus Corynebacterium are not currently available. This study aimed to evaluate the usefulness of matrix-assisted laser desorption ionization/mass spectrometry (MALDI-TOF MS) for identifying Corynebacterium spp. isolated from the mammary glands of dairy cows. Corynebacterium spp. were isolated from milk samples via microbiological culture (n=180) and were analyzed by MALDI-TOF MS and 16S rRNA gene sequencing. Using MALDI-TOF MS methodology, 161 Corynebacterium spp. isolates (89.4%) were correctly identified at the species level, whereas 12 isolates (6.7%) were identified at the genus level. Most isolates that were identified at the species level with 16 S rRNA gene sequencing were identified as Corynebacterium bovis (n=156; 86.7%) were also identified as C. bovis with MALDI-TOF MS. Five Corynebacterium spp. isolates (2.8%) were not correctly identified at the species level with MALDI-TOF MS and 2 isolates (1.1%) were considered unidentified because despite having MALDI-TOF MS scores >2, only the genus level was correctly identified. Therefore, MALDI-TOF MS could serve as an alternative method for species-level diagnoses of bovine intramammary infections caused by Corynebacterium spp.
authors.affiliation: Department of Animal Science, School of Veterinary Medicine and Animal Science (USP), Pirassununga, SP, Brazil.
authors.forename: Juliano Leonel
authors.initials: JL
authors.lastname: Gonçalves
authors.affiliation: Department of Animal Science, School of Veterinary Medicine and Animal Science (USP), Pirassununga, SP, Brazil.
authors.forename: Tiago
authors.initials: T
authors.lastname: Tomazi
authors.affiliation: Department of Animal Science, School of Veterinary Medicine and Animal Science (USP), Pirassununga, SP, Brazil.
authors.forename: Juliana Regina
authors.initials: JR
authors.lastname: Barreiro
authors.affiliation: ThoMSon MS Laboratory, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Patrícia Aparecida de Campos
authors.initials: PA
authors.lastname: Braga
authors.affiliation: ThoMSon MS Laboratory, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Christina Ramires
authors.initials: CR
authors.lastname: Ferreira
authors.affiliation: Institute of Biosciences, State University of São Paulo "Júlio de Mesquita" (UNESP), Botucatu, SP, Brazil.
authors.forename: João Pessoa
authors.initials: JP
authors.lastname: Araújo Junior
authors.affiliation: ThoMSon MS Laboratory, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Marcos Nogueira
authors.initials: MN
authors.lastname: Eberlin
authors.affiliation: Department of Animal Science, School of Veterinary Medicine and Animal Science (USP), Pirassununga, SP, Brazil. Electronic address: mveiga@usp.br.
authors.forename: Marcos Veiga
authors.initials: MV
authors.lastname: dos  Santos
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D003352:Corynebacterium / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D003354:Corynebacterium Infections / Q000382:microbiology / Q000662:veterinary*; D003612:Dairying; D005260:Female; D020459:Genes, rRNA; D008321:Mammary Glands, Animal / Q000382:microbiology; D008892:Milk / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D012336:RNA, Ribosomal, 16S
keywords: Corynebacterium spp.; Mass spectrometry; Subclinical mastitis