What is behind phylogenetic analysis of hospital‐, community‐ and livestock‐associated methicillin‐resistant Staphylococcus aureus ?

Summary Methicillin‐resistant Staphylococcus aureus ( MRSA ) has been shown to be the predominant life‐threatening pathogen in Egypt. MRSA is a major cause of severe healthcare‐associated ( HA ) infections. During the last decades, the incidence of community‐associated ( CA ) MRSA infections has a complex epidemiology arising from the circulation of different strains in the general population. Moreover, livestock‐associated ( LA ) MRSA emerged recently becomes an emerging threat to public health. Therefore, it is important to illuminate the differences between CA ‐, HA ‐ and LA ‐ MRSA to shed light on their genetic diversity and evolution. This study presents the first data on analysing the correlation between CA ‐, LA ‐ and HA ‐ MRSA using antibiogram typing, molecular characteristics and antimicrobial resistance and virulence genes’ profiles. Overall, HA ‐ MRSA strains tended to be multidrug resistant and less virulent than both LA ‐ and CA ‐ MRSA strains. Importantly, CA ‐ MRSA strains had a high homology with each of HA ‐ and LA ‐ MRSA . However, no similarity was observed between HA ‐ and LA ‐ MRSA . Our findings suggest that the epidemiological changes in genetic behaviour between HA ‐ and LA ‐ MRSA are due to the presence of CA ‐ MRSA confirming that CA ‐ MRSA has created a public health crisis worldwide.