The continuing threat of methicillin-resistant Staphylococcus aureus- Past Present Future

Methicillin-resistant Staphylococcus aureus has been a major problem in the worldwide health care centres and institutions since the last 60 years . It has been a major pathogen responsible for nosocomial infections and recently has created life-threatening situations. Penicillin resistance was seen a few years after the drug was introduced. To solve this problem another drug of the penicillin family was introduced : the semi- synthetic methicillin or oxacillin. This solved the antibiotic resistance for a while until in 1960 in the UK, strains of Staphylococcus aureus were isolated that showed resistance to methicillin thus termed as Methicillin-resistant Staphylococcus aureus MRSA or Superbug. In the previous few decades MRSA has shown increased resistance not only to methicillin but also to a wide range of other antibiotics such as gentamycin, erythromycin, and tetracycline .After the emergence of multidrug resistance in MRSA, the only drug of choice for treating MRSA infections was the glycopeptide vancomycin. It was considered the drug of "last resort" until the unfortunate emergence of another alarming mutated strains of MRSA-Vancomycin-intermediate Staphylococcus aureus (VISA), and now recently the biggest threat of all is vancomycin-resistant Staphylococcus aureus (VRSA) which has acquired Vancomycin vanA gene from Enterococcus faecalis. The emergence of VISA or VRSA isolates alone are the huge threat mankind faces. Thus it has become imperative that analysis of MRSA strains take place and their genetic characteristics may be well understood to fight against the evolution of MRSA into VISA or VRSA.