Direct identification of bovine mastitis pathogens by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in pre-incubated milk
Braz. j. microbiol
; 49(4): 801-807, Oct.-Dec. 2018. tab, graf
Article
en En
| LILACS
| ID: biblio-974302
Biblioteca responsable:
BR1.1
ABSTRACT
ABSTRACT The present study aimed to compare two MALDI-TOF identification methods [(a) direct sample identification after pre-incubation; or (b) use of bacteria isolated on pre-culture)] to standard, traditional bench microbiology. A total of 120 quarter milk samples from 40 Holstein lactating cows were screened based on culture-positive results obtained by microbiological culture (reference method) with the following numbers of quarters positive per cow 4 cows with 1, 8 cows with 2, 12 cows with 3 and 16 cows with 4 infected quarters per cow. For direct identification method, quarter milk samples (n = 120) were skimmed by centrifugation (10,000 × g/10 min) and pre-incubated at 37 ºC for 12 h. After pre-incubation, quarter milk samples were submitted to total bacterial count by flow cytometry and for a preparation protocol for bacterial ribosomal protein extraction followed by MALDI-TOF MS analysis. The direct MALDI-TOF MS identification method compared to microbiological culture correctly identified isolates of coagulase-negative Staphylococci (27.2%), Streptococcus agalactiae (21.8%), Staphylococcus aureus (14.2%), and Streptococcus uberis (5.2%). The pre-incubation protocol of milk samples, associated to the direct identification method by MALDI-TOF MS, did not increase the identification at species level (score >2.0) of pathogens causing subclinical mastitis in comparison to the method without previous incubation.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
LILACS
Asunto principal:
Staphylococcus
/
Streptococcus
/
Técnicas de Tipificación Bacteriana
/
Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
/
Leche
/
Mastitis Bovina
Tipo de estudio:
Diagnostic_studies
/
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Braz. j. microbiol
Asunto de la revista:
MICROBIOLOGIA
Año:
2018
Tipo del documento:
Article
País de afiliación:
Brasil
Pais de publicación:
Brasil