Science and Technology Production
Heifers introduced a new subtype into a herd with persistent Staphylococcus aureus intramammary infections
Article
Authorship:
Cicotello, Joaquin ; Ramezanigardaloud, Nasrin ; Miotti, Camila ; Molineri, Ana Inés ; Grunert, Tom ; Suarez Archilla, Guillermo ; Calvinho, Luis Fernando ; CAMUSSONE, CECILIA MARIADate:
2025Publishing House and Editing Place:
CAMBRIDGE UNIV PRESSMagazine:
Journal of Dairy Research, vol. 91 (pp. 420-426) CAMBRIDGE UNIV PRESSSummary *
This study describes the spread of intramammary infections (IMI) during the first lactation ofheifers that were naturally infected with Staphylococcus aureus before parturition and introducedinto a herd with a high prevalence of this organism. The heifers were monitored duringtheir first lactation to determine potential spread and persistence of IMI and to characterizethe isolates that caused IMI. Milk samples were obtained from all the cows in the lactatingherd at the beginning of the study and one year later. S. aureus isolated at both these samplingtimes were compared with those obtained from the heifers to analyse their clonal and phylogeneticrelationships, employing pulse-field gel electrophoresis (PFGE), multi-locus sequencetyping and Fourier transform infrared spectroscopy. Most S. aureus isolated from mammarysecretions of heifers before parturition established chronic IMI during the first lactation. PFGEtyping discriminated 3 clusters that were associated with origin of isolates, number of lactationsand clonal complex. Differences both in the presence and expression of genes associatedwith virulence determinants among the major pulsotypes infecting lactating cows and thosefrom heifers that developed persistent IMI were detected, which are indicative of distinctadaptive capacities to generate IMI. Information provided by the agent in SIGEVAKey Words
Heifersintramammary infectionsStaphylococcus aureus