Non-culture-based identification of mastitis-causing bacteria by MALDI-TOF mass spectrometry

Autor(es)

Barreiro, Juliana Regina ; Goncalves, Juliano Leonel ; Campos Braga, Patricia Aparecida ; Dibbern, Aline Gerato ; Eberlin, Marcos Nogueira ; dos Santos, Marcos Veiga

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF DAIRY SCIENCE; v. 100, n. 4, p. 2928-2934, APR 2017.
• Citações Web of Science: 13

Resumo

The purpose of this study was to evaluate the detection limit of matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF MS) for direct identification, without previous microbiological culture, of bovine mastitis-causing bacteria from milk samples. Milk samples (n = 15) were experimentally contaminated with Staphylococcus aureus, Streptococcus uberis, Streptococcus agalactiae, Streptococcus dysgalactiae, and Escherichia coli to have bacterial counts ranging from 103 to 106 cfu/mL. These contaminated milk samples were subjected to a preparation protocol for bacterial ribosomal protein extraction using the MALDI Sepsityper kit (Bruker Daltonik, Bremen, Germany), which allowed MALDI-TOF MS coupled with Biotyper software (Bruker Daltonik) to identify bacterial fingerprints based on intact ribosomal proteins. The ability of MALDI-TOF MS to correctly identify bacterial strains from experimentally contaminated milk (without previous microbiological culture) depended on the bacterial count of the samples and on the species of the bacteria evaluated. Adequate identification at the bacterial species level (score >= 2.0) directly from milk samples required bacterial counts in the following ranges: >= 10(6) cfu/mL of Staph. aureus, >= 10(7) cfu/mL of E. coli, and >= 10(8) cfu/mL of Strep. agalactiae, Strep. dysgalactiae, and Strep. uberis. We concluded that direct identification of mastitis-causing pathogens is possible for Staph. aureus, E. coli, Strep. agalactiae, Strep. dysgalactiae, and Strep. uberis, but correct identification depended on the bacterial count in the milk samples. (AU)

• Processo FAPESP: 11/15815-4 - Identificação rápida de microrganismos causadores de mastite por espectrometria de massas
• Beneficiário: Marcos Veiga dos Santos
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 11/14456-0 - Identificação rápida de microrganismos causadores de mastite por espectrometria de massas
• Beneficiário: Juliana Regina Barreiro
• Modalidade de apoio: Bolsas no Brasil - Doutorado