Open AccessStaphylococcus aureus Host Range and Human-Bovine Host Shift
Author(s) -
Olga Sakwińska,
Marlyse Giddey,
Martine Moreillon,
Delphine Morisset,
Andreas Waldvogel,
Philippe Moreillon
Publication year - 2011
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.00238-11
Subject(s) - multilocus sequence typing , mastitis , biology , staphylococcus aureus , genotype , carriage , microbiology and biotechnology , typing , staphylococcal infections , amplified fragment length polymorphism , transmission (telecommunications) , host (biology) , pathogen , virology , genetics , genetic diversity , population , gene , medicine , bacteria , environmental health , electrical engineering , engineering , pathology
Staphylococcus aureus is a major agent of bovine mastitis. The concomitant emergence of pig-associated methicillin-resistantS. aureus (MRSA) in human carriage and infection requires a reexamination of the host range and specificity of human- and cow-associatedS. aureus strains, something which has not been systematically studied previously. The genetic relatedness of 500S. aureus isolates from bovine mastitis cases, 57 isolates from nasal carriage of farmers, and 133 isolates from nonfarmers was determined by amplified fragment length polymorphism (AFLP) analysis andspa typing. Multilocus sequence typing (MLST) was conducted on a subset of isolates to match AFLP clusters with MLST clonal complexes (CCs). This data set allowed us to study host range and host specificity and to estimate the extent of bovine-to-human transmission. The genotype compositions ofS. aureus isolates from farmers and nonfarmers were very similar, while the mastitis isolates were quite distinct. Overall, transmission was low, but specific genotypes did show increased cow-to-human transmission. Unexpectedly, more than one-third of mastitis isolates belonged to CC8, a lineage which has not been considered to be bovine mastitis associated, but it is well known from human carriage and infection (i.e., USA300). Despite the fact that we did detect some transmission of other genotypes from cows to farmers, no transmission of CC8 isolates to farmers was detected, except for one tentative case. This was despite the close genetic relatedness of mastitis CC8 strains to nonfarmer carriage strains. These results suggest that the emergence of the new bovine-adapted genotype was due to a recent host shift from humans to cows concurrent with a loss of the ability to colonize humans. More broadly, our results indicate that host specificity is a lineage-specific trait that can rapidly evolve.