Why is Staphylococcus aureus Such a Successful Pathogen?

Staphylococcus aureus is a fast evolving and a well-adapted opportunistic pathogen that causes a variety of infections such as boils, abscesses, pneumonia, toxic shock syndrome, endocarditis, bacteraemia and food poisoning in humans. The colonisation of various body sites by S. aureus demonstrates the ability of this pathogen to disseminate at a fast pace in the hospital setting and in the community. The organism is endowed with a profusion of virulence factors that play a significant role in pathogenesis and disease severity. S. aureus infections are generally difficult to treat due to the evolution of strains with resistance to methicillin (methicillin-resistant S. aureus-MRSA) and vancomycin (vancomycin intermediate-resistant S. aureus [VISA] and vancomycin-resistant S. [VRSA]). The success of S. aureus as a human pathogen, therefore, relies largely on its capacity to produce an array of virulence factors that can evade or subvert the host immune responses and its resistance to a wide range of antibiotics. This review will focus largely on virulence determinants, immune evasion mechanisms and antibiotic resistance mechanism of S. aureusthat makes it such a successful pathogen.