Evolution, Characteristics, and Clonal Expansion of Livestock-Associated Methicillin-Resistant Staphylococcus aureus (LA-MRSA): Global Perspectives

Abstract

Epidemiological classification of methicillin-resistant Staphylococcus aureus (MRSA) as hospital-associated MRSA (HA-MRSA), community-associated MRSA (CA-MRSA), and livestock-associated MRSA (LA-MRSA) has become more complex and unclear. Nevertheless, the global burden of LA-MRSA and its clinical complications have been increased to unprecedented levels. The improper use of antibiotics contributed to the emergence of MRSA in the livestock sector. Apart from infections, asymptomatic colonization of MRSA in humans and animals can result in the humanosis and/or zoonosis. The LA-MRSA studies drew attention because of its unique properties of harboring the mecC locus (an analogue of mecA) as the methicillin resistance determinant and varying staphylococcal cassette chromosome mec (SCCmec) elements. The peculiar feature of LA-MRSA which is non-typeable by SmaI-pulsed-field gel electrophoresis (SmaI-PFGE) has opened different vistas in LA-MRSA research. The present chapter focused on the prevalence, history of evolution, clonal expansion, and epidemiological characteristics of LA-MRSA from global perspectives. Concerted efforts were made to encompass the major aspects of LA-MRSA by analyzing the related studies. Over the years, LA-MRSA gained special attention owing to its widespread and zoonotic potential.