Winning the battle but losing the war: methicillin-resistant Staphylococcus aureus (MRSA) infection at a teaching hospital

A methicillin-resistant Staphylococcus aureus (MRSA) control policy, aimedat eradication, was established at a 1000-bed hospital in 1985, appliedconsistently for 10.5 years, and then relaxed. Its components includedscreening of high-risk patients, transfer of carriers to exhaust-ventilatedisolation rooms, closure of wards to new admissions when local transmissionwas detected, MRSA screening during outbreaks, and prospective collectionof clinical and epidemiological information. During the eradication policyperiod, every 6 months, a mean of 5.1 patients (range 1-12) alreadycarrying MRSA were admitted, and a mean of 3.6 (range 0-16) acquiredcarriage in the hospital. The largest outbreak comprised 11 patientsdespite epidemic MRSA strain EMRSA-16 being introduced six times, and MRSAdid not become endemic. MRSA- positive admissions increased progressivelyfrom 1993; nursing staff workload increased, areas available foralternative patient accommodation were reduced, the resulting ward closuresinterfered with clinical services, and hence the control policy was relaxedin mid- 1995. Isolation facilities were overwhelmed with 622 new patient-isolates in the next 18 months, and there were 67 clinical infections in1996. The proportion of blood cultures positive for MRSA rose nearlysevenfold by 1996 and 27-fold by 1997. Thus, repeated eradication of MRSA,even epidemic strains, by use of a stringent policy, is possible givensufficient resources, whereas flexible national guidelines designed tocontrol, but not eradicate, epidemic staphylococci, are currently unlikelyto be successful. The costs of eradication policies need to be weighedagainst those of endemicity.