Diversity of livestock associated methicillin-resistant Staphylococcus aureus

To evaluate the diversity and molecular characteristics of livestock associated methicillin-resistant Staphylococcus aureus in livestock animals, food of animal origin and the environment in the Czech Republic.

After having been primarily enriched in buffered peptone water, the samples were cultured on Baird-Parker agar. Presumptive colonies were sub-cultured to blood agar and assessed morphologically. Furthermore, presumptive Staphylococcus aureus colonies were confirmed by MALDI-TOF. Multiplex PCR, spa-typing, and MLST have been used to characterize the strains. Each mecA-positive Staphylococcus aureus isolates were examined against 14 different antimicrobials by using disk diffusion method.

In this study, 13 different spa-types belonging to five sequence types (ST) were detected. Ninety four percent of tested strains belonged to CC/ST398 for which t011, t034, t2123 and t2346 were the vast major spa-types. In addition, non-ST398 clones such as CC1(t127), ST5(t3598), ST8(t064) and ST361(t315) were detected, which are known as human associated clones.

The diversity of livestock associated methicillin-resistant Staphylococcus aureus has grown, and detecting lineages of human origin in animals and vice-versa becomes more common. Thus, livestock animal and its products will be a potential for the evolvement of methicillin-resistant Staphylococcus aureus in human population. Monitoring of pigs as well as other food-producing animal species and their products is therefore recommended.