Antimicrobial resistance in methicillin-resistant Staphylococcus aureus to newer antimicrobial agents.

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) result in significant morbidity and mortality for patients in both community and health care settings. This is primarily due to the difficulty in treating MRSA, which is often resistant to multiple classes of antibiotics. Understanding the mechanisms of antimicrobial resistance (AMR) in MRSA provides insight into the optimal use of antimicrobial agents in clinical practice and also underpins critical aspects of antimicrobial stewardship programs. In this review we delineate the mechanisms, prevalence, and clinical importance of resistance to antibiotics licensed in the past 20 years that target MRSA, as well as new drugs in the pipeline which are likely to be licensed soon. Current gaps in scientific knowledge about MRSA resistance mechanisms are discussed, and topics in the epidemiology of AMR in S. aureus that require further investigation are highlighted.