Update on major clones of methicillin-resistant Staphylococcus aureus colonizing and/or infecting humans and its distribution in Brazil

Staphylococcus aureus is a bacterium well known for its ability to acquire genes for resistance to antimicrobial drugs. A few years after the discovery of penicillin, which initiated the era of antibiotics, resistance to this drug had already been reported in hospitals and in a few decades also became a problem within the communities. Likewise, shortly after the introduction of methicillin as a therapeutic option, the resistance was observed. The indiscriminate use of antibiotics is an important factor contributing to the emergence of new resistant strains. This pathogen has the ability to spread rapidly and asymptomatically among healthy individuals. Infections caused by Methicillin-Resistant Staphylococcus aureus (MRSA) have reached a global share and are increasing in hospitals and community, including countries that previously had a low prevalence of MRSA history, exposing a significant diversity of clones identified. Outbreaks of infections caused by strains of Community-Associated Methicillin-Resistant Staphylococcus aureus (CA-MRSA) have been reported worldwide, including Brazil, where there is currently an epidemic of CA-MRSA. The present article intends to review the molecular epidemiology of methicillin-resistant Staphylococcus aureus and its evolution, with a focus on the clones distributed in Brazil.