Methicillin-Resistant Staphylococcus aureus (MRSA): Molecular Aspects of Antimicrobial Resistance and Virulence

Extract

Awareness of the threat of MRSA is growing. Scientists have put a lot of effort into trying to divide and classify MRSA strains into groups to better understand it. This led to the discovery that the resistance gene, mecA, and surrounding DNA could be grouped into several types. It was also discovered that the MRSA strains that caused hospital-acquired (nosocomial) infections were different strains than those seen in the communities. Several studies led to the realization that the number of MRSA infections is increasing, that more Staphylococcus aureus infections are caused by MRSA strains, and that the community strains are now showing up in the hospital. There have been government initiatives to try to decrease MRSA infections, with the most perplexing issue being that of whether or not to perform surveillance cultures on as many people as possible to eradicate MRSA from the community, as well as the hospital.

When penicillin was first used against bacteria like Staphylococcus aureus, medical science thought that this bug had been conquered. Unfortunately, within a short space of time, penicillin-resistant strains of S. aureus were being isolated. The search for the cause of this resistance led to the discovery of the penicillin-binding proteins (PBPs), so named because of their role in how penicillin affects the bacteria. The PBPs are actually transpeptidases that are involved in the construction of the peptidoglycan portion of the bacterial cell wall. Their function is in catalyzing reactions that allow the cross-linking of the peptidoglycan subunits. When penicillin invades the…