Mechanisms of Methicillin Resistance in Staphylococcus aureus

Abstract

Staphylococcus aureus is a major human and veterinary pathogen worldwide. Methicillin-resistant S. aureus (MRSA) poses a significant and enduring problem to the treatment of infection by such strains. Resistance is usually conferred by the acquisition of a nonnative gene encoding a penicillin-binding protein (PBP2a), with significantly lower affinity for β-lactams. This resistance allows cell-wall biosynthesis, the target of β-lactams, to continue even in the presence of typically inhibitory concentrations of antibiotic. PBP2a is encoded by the mecA gene, which is carried on a distinct mobile genetic element (SCCmec), the expression of which is controlled through a proteolytic signal transduction pathway comprising a sensor protein (MecR1) and a repressor (MecI). Many of the molecular and biochemical mechanisms underlying methicillin resistance in S. aureus have been elucidated, including regulatory events and the structure of key proteins. Here we review recent advances in this area.

A Study on Methicillin Resistant Coagulase Negative Staphylococci Isolated From Medical Intensive Care Unit at a Tertiary Care Centre - India

“…This difference (2.58%) in their resistance pattern probably represents that not only mecA gene but also there are some other mechanisms are responsible for the resistance 11 .A study by Cookson et al 12 showed that 100% of MRCONS were Penicillin resistant which is same as present study. Singh.…”

A Review of <i>Staphylococcus aureus</i> and the Emergence of Drug-Resistant Problem

“…Unfortunately, the rate of drug-resistant in human S. aureus isolates is over 90%. That is to say, penicillin almost lost therapeutical effect [7]. Worse to come, S. aureus was capable of resisting other antibiotics such as erythromycin, streptomycin, and the tetracyclines [63] [64] [65].…”

A Frequency and Molecular Typing Study of Methicillin-Resistant Staphylococcus aureus Isolates in Teaching Hospitals in Shahrekord, SouthWestern Iran

“…The potential of S. aureus to develop resistance rapidly to many antibiotics has led to the emergence of methicillinresistant S. aureus (MRSA) (1,2). Methicillin resistance is associated with the production of the PBP2a protein by the mecA gene.…”

“…Methicillin resistance is associated with the production of the PBP2a protein by the mecA gene. This gene is located on a 30 -50 kb chromosomal DNA fragment, which is present in resistant strains but absent in susceptible ones (2,3). The staphylococcal cassette chromosome mec (SCCmec) is a mobile genetic element that carries the mecA gene and other antibioticresistant genes in MRSA strains (4,5).…”