GENESIS OF METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS (MRSA), HOW TREATMENT OF MRSA INFECTIONS WAS SELECTED FOR VANCOMYCIN-RESISTANT ENTEROCOCCUS-FAECIUM, AND THE IMPORTANCE OF ANTIBIOTIC MANAGEMENT AND INFECTION-CONTROL

We extensively studied the epidemiology and time course of endemic met hicillin-resistant Staphylococcus aureus (MRSA) in the Millard Fillmor e Hospital, a 600-bed teaching hospital in Buffalo. The changeover fro m methicillin-susceptible S. aureus to MRSA begins on the first hospit al day, when patients are given cefazolin as presurgical prophylaxis. Under selective antibiotic pressure, colonizing flora change within 24 to 48 hours. For patients remaining hospitalized, subsequent courses of third-generation cephalosporins further select and amplify the colo nizing MRSA population. Therefore, managing antibiotic selective press ure might be essential. Other strategies include attention to dosing, so that serum concentrations of drug exceed the minimum inhibitory con centration, and antibiotic cycling. Although there are some promising new antibiotics on the horizon, it is necessary to deal with many resi stance patterns by using the combined strategies of infection control and antibiotic management.