Methicillin-resistant Staphylococcus aureus (MRSA) strains belonging to sequence type (ST) 398 are being reported with increasing frequency in Europe and other countries. This MRSA type has been isolated from colonized and infected animals and humans. The aim of this study was to determine the prevalence of nasal MRSA carriage in pigs and pig workers. A total of 300 pigs from 15 different farms were sampled in the slaughterhouse of Tenerife. A total of 54 pig workers were screened for MRSA: 20 belonged to farms whose pigs had been sampled and 34 to the slaughterhouse. The percentage of positive samples of MRSA in pigs was 85.7%. The overall prevalence of nasal MRSA carriage in pig workers was 9.3%. All MRSA isolates from pigs and humans belonged to one clonal group showing multilocus sequence type (MLST) 398. Two types of Staphylococcal Chromosome Cassette (SCCmec) were found, IV and V. In conclusion, the prevalence of MRSA in nasal samples from pigs and pig workers in Tenerife was high. We therefore consider it essential to deepen epidemiological study of this strain of animal origin, as well as to increase surveillance and control measures at all stages of the food chain.

Background: Livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) such as the MRSA ST398 strain has spread all over the World and the most worrying aspect of this fact appears to be its capacity to easily spread to humans. The excessive use of antibiotics has made swine a reservoir of MRSA. The aim of the present study was to determine the antibiotic resistance profile of MRSA samples isolated from healthy swine of the island of Tenerife (Spain). Methods: A total of 256 MRSA isolates from swine samples and five MRSA isolates from pig worker samples were investigated for MRSA antibiotic resistant patterns. Results: Analysis of the susceptibility status of MRSA pig isolates revealed that 39 isolates were resistant to one antibiotic, 71 isolates were resistant to two antibiotics and 96 isolates were resistant to three or more antibiotics. SCCmec typing revealed the presence of types IV and V. Isolates having SCCmec IV had an increased resistance to the antimicrobial agents tested than those having SCCmec V. We observed significant differences when comparing the most common resistance patterns and SCCmec type. Conclusions: MRSA isolated from humans showed similar resistance to those isolated from pigs, excepting erythromycin, since all the workers’ isolates were sensitive to this antibiotic. The evolution of new MRSA clones has emphasized the need for infection control practices in animals and humans in close contact.