Methicillin-resistant Staphylococcus aureus infections

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) has continued to spread and cause serious nosocomial infections. Failure to control MRSA may result in higher rates of use of glycopeptides, which may, in turn, lead to higher rates of glycopeptide resistance. Resistance to glycopeptides has recently begun to appear in S. aureus. Transfer of glycopeptide-resistance genes from enterococci to S. aureus has been documented in laboratory experiments but has not yet been found in clinical isolates. Over time, MRSA is becoming more common in various subsets of the general population. Some studies claim that many MRSA-colonized outpatients and their close contacts have had no health care contacts, but these studies have usually not considered contacts in outpatient clinics. Several other recent studies have found that all or a vast majority of patients with MRSA have had frequent contact with health care providers. Failure to wash hands and disinfect equipment between patients, which has been commonly seen in studies of health care worker compliance with infection control measures, may explain much of the continuing spread. The source of spread of antibiotic-resistant microbes can be likened to an iceberg, with clinically obvious infections representing the tip of the iceberg and most of the spread coming from clinically inapparent colonized patients who represent most of the reservoir for transmission. Surveillance cultures to identify this reservoir are important to the control of spread with effective barrier precautions. Such precautions have been shown to reduce the spread of MRSA 15.6-fold compared with standard precautions.

Efficacy of an alcohol/chlorhexidine hand hygiene program in a hospital with high rates of nosocomial methicillin‐resistant Staphylococcus aureus (MRSA) infection

“…Once introduced into a hospital, MRSA can be spread until a large silent reservoir of colonised patients develops. By the time serious infections such as bacteraemia draw attention to the problem, asymptomatic colonisation will typically be widespread 8 and contamination of the environment may be extensive 9 , 10 . These observations suggest that improved hand hygiene by health care workers and better cleaning of shared hospital equipment could reduce the likelihood of patients becoming colonised and lead to subsequent reductions in MRSA infection.…”

Antibiotics

“…In clinical routine, only a small number of MRSA patients are identified, because microbiological analysis is usually performed only when clinically indicated-i.e., when bacterial infection is suspected (6). How many clinically inapparent MRSA colonizations are actually represented in a reservoir for possible nosocomial spread of infection is so far unknown.…”