Decreased antimicrobial resistance after changes in antibiotic use.

Vancomycin-resistant enterococci (VRE) and methicillin-oxacillin-resistant Staphylococcus aureus (MRSA) originally predominated in large medical centers; however, these isolates are now common in community hospitals and community clinics. No simple answer is available regarding control of antimicrobial-resistant bacteria, especially VRE and MRSA, as their numbers increase and pose a more serious threat to patient care. The source of colonization is often difficult to identify because of transport of patients among different locations on the continuum of care (e.g., hospital to extended care facility to home and back). At one hospital, control strategies greatly reduced the occurrence of gram-negative bacteria such as VRE. Since 1994, VRE declined from 16% to 5%. Similarly, the number of MRSA isolates declined from 35% to 23%. These declines are attributed to a cohesive working relationship among pharmacists, microbiologists, and infectious disease physicians and personnel, and to a decision to decrease administration of cephalosporins in favor of piperacillin-tazobactam.