Phenotypic variations of staphylococcal pathogenesis: a comprehensive review

Gram positive Staphylococcus strains causes variety of infection ranging from mild skin infections to life threatening infections. Its pathogenicity is due to its ability to produce virulence factors i.e. exotoxins, enzymes and surface adhesions. 90% of staphylococcal infections are caused by strains that produces virulence factors while 40–50% are resistant to commonly available antibiotics. The emergence of resistance is often related with phenotypic variations i.e. biofilm formation and the altered membrane permeability. The review also covers mechanism of pathogenesis of staphylococcal that includes the interplay of variety of virulence factors that staphylococcal bacteria produces, i.e. protein A, FnBPs and α toxins. The FnBPs have role in colonization, promotion of antibiotic resistance, biofilm formation and invasion of immune responses. Biofilm formation has significant role as a manifestation of phenotypic variations in staphylococcal strains and in pathogenesis of various diseases i.e. osteomyelitis, endocarditis catheter related bloodstream and infections associated with medical devices. Various genetic factors are involved in biofilm formation including agr system and the aca operon. Biofilm present on the joint's replacement demonstrates increased persistence and antibiotic resistance. Phenotypic variations of Staphylococcus strains play significant role in pathogenesis of various diseases. Further research and development at molecular level is needed to better understand the mechanism of biofilm formation and identification of new therapeutic targets of biofilm. This review provides an insight into strategies for treating and preventing staphylococcal biofilm associated infections.