[Methicillin-resistance of staphylococci and methods of detection]

Abstract

In Hungary more than 25% of Staphylococcus aureus strains and 33.4-70.1% of strains of different coagulase-negative Staphylococcus species isolated from inpatients in the last five years were methicillin-resistant. These are great clinical problems because the methicillin-resistant strains are resistant to all beta-lactam antibiotics, furthermore, most of them exhibit multiple resistance, too. For these reasons, the fast and exact microbiological diagnosis is of utmost basic and life-saving importance. In this review the most important evidences for proving pathogenicity and virulence of methicillin-resistant S. aureus strains and our knowledge on the origin, genetic background, conditions of expression, forms of appearance, phenotypical and genotypical properties of methicillin resistance are summarised. Phenotypical semiquantitative and quantitative methods aiming the detection of methicillin resistance are shown with their advantages and restrictions. Genetic methods applicable to detect mecA gene responsible for coding methicillin resistance, furthermore, those by which clonal and genomic relationship and spread can be proven in epidemic cases are presented. Finally, up-to-date schemes for a proper identification as well as systemic and local elimination of methicillin resistant Staphylococcus strains are suggested.