Methicillin-resistant Staphylococcus aureus (MRSA) in developing and developed countries: implications and solutions

Methicillin-resistant Staphylococcus aureus (MRSA) is a global public health problem, associated with considerable morbidity and mortality. The MRSA infections can be hospitalor community-acquired. Hospital-associated MRSA (HA-MRSA) characteristically colonizes or infects hospitalized individuals with predisposing risk factors, usually harbours SCCmec type I, II or III, and is multi-drug resistant (MDR). In contrast, community-associated MRSA (HA-MRSA) infects healthy individuals without any previous healthcare contact, often harbours smaller and more mobile SCCmec types, is usually Panton-Valentine leucocidin (PVL) positive, susceptible to non-β-lactam antimicrobial drugs, and frequently manifests as skin and soft-tissue infections. However, this distinction between CAand HA-MRSA is gradually fading owing to the emergence of pvl negative and/or MDR CA-MRSA clones, and its invasion into hospitals. The incidence of HAand CA-MRSA infections, as well as the relative abundance of different MRSA clones varies considerably among countries. The HA-MRSA is endemic in many hospitals worldwide. The CAMRSA has a smaller fitness burden, higher transmissibility and virulence compared to HA-MRSA, and is epidemic in many geographical locations. In addition, some MRSA clonal lineages exhibit superior survival and transmissibility, and are more frequently isolated than others. Limited options are available for the therapeutic management of MRSA infections. The CA-MRSA-associated skin and soft-tissue infections are treated with oral antibiotics including doxycycline, minocycline, clindamycin, trimethoprimsulfamethoxazole, rifampicin and fusidic acid. Severe CA-MRSA infections and HA-MRSA necessitate intravenous vancomycin therapy. Asymptomatic carriers represent an important MRSA reservoir. The transmission of MRSA infections may be limited by universal infection-control measures, patient education, screening and decolonization of asymptomatic MRSA carriers in both health-care and community settings.