Methicillin-resistant Staphylococcal aureus evolution in Australia over 35years

Australia has a long association methicillin-resistant Staphylococcus aureu s (MRSA), Its unique geographic and demographic features have led to the em ergence and spread of three types of MRSA over 35 years. Classical multires istant hospital-acquired MRSA were first noted in Australia in 1965, By the end of the 1970s, strains of this type of MRSA were well established in th e complex tertiary care hospitals in the capital cities on the eastern seab oard of mainland Australia. Characterized by resistance to beta -lactams, e rythromycin, tetracycline, gentamicin, and trimethoprim-sulfamethoxazole, t hese strains have persisted and diversified genetically and have acquired a variety of new resistances, They have proven pathogenicity and are a promi nent cause of hospital infection in the endemic institutions. More recently they have become endemic in some central state tertiary care hospitals. Co mmunity-acquired strains of MRSA first appeared in the north of Western Aus tralia in the mid-1980s, Strains have subsequently appeared in the south of the state and in the two adjacent central states, and are more frequently isolated from Aboriginal patients. Although harboring few or no additional resistances apart from resistance to beta -lactams initially, these strains are also accumulating additional resistances. A different variety of commu nity-acquired MRSA has recently been noted in eastern Australia, It has a s imilar antibiogram to the western strains, but an entirely different epidem iology, resembling that currently being experienced in parts of New Zealand , and associated with patients of south Pacific island origin.