Antimicrobial resistance.

548 This symposium highlights selected topics in antimicro-bial resistance: community-acquired methicillin-resistant Staphylococcus aureus, malaria, reducing inappropriate antimicrobial drug prescribing for outpatient respiratory infections, and addressing the human health impact of antimicrobial drug use in food animals. Dr. Timothy Naimi discussed community-acquired methicillin-resistant Staphylococcus aureus (CMRSA) infections , which have been reported in the Western Pacific and North America with increasing frequency. Few incidence data are available, but reports show a disproportionate distribution among racial minorities and groups with low socioeconomic status. CMRSA infections resembled community acquired methicillin-susceptible S. aureus infections more than MRSA infections acquired in health-care facilities. Patients with CMRSA were young, healthy, and lacked risk factors for MRSA (recent hospitalization, dialysis, and injection drug use), and they had predominantly skin and soft tissue infections; four deaths due to invasive CMRSA infections were reported in the United States. Unlike nosocomial MRSA, CMRSA is sensitive to multiple non-beta-lactam antibiotics. CMRSA isolates have the mec A gene and distinct pulsed-field-gel electrophoresis patterns. CMRSA presents a clinical challenge because most community-acquired S. aureus infections are diagnosed without taking a culture, and the patient is treated with beta-lactam drugs. Improved surveillance and efforts to define risk factors are under way. Dr. Pascal Ringwald reviewed antimalarial drug resistance, which greatly hinders malaria control since no vaccine will be available in the near future. Resistance of Plasmodium falciparum to chloroquine, the most frequently used antimalarial drug, is found in nearly all malaria-endemic countries. Resistance also affects all other antimalarial drugs; cross-resistance occurs against drugs in the same group. In recent years, chloroquine-resistant P. vivax has been reported in Southeast Asia and in South America. Drug resistance increases illness and death, especially among children. As the number of new antimalarial agents is limited, the use of drug combinations is under evaluation. WHO supports national malaria control programs to monitor antimalarial drug resistance in sentinel sites. Decisions to change drug policy should be based on the results of monitoring in these sites. The establishment of a new policy must entail a rational use of drugs and improved compliance. Dr. Richard Besser discussed efforts to reduce inappropriate antibiotic prescribing for outpatient respiratory infections in the United States. Over 40% of outpatient antibiotic prescriptions are for viral illnesses, which are not affected by antibiotics. CDC's educational campaign, targeted to clinicians and patients, involves partnerships with health departments, health-care delivery organizations, health-care purchasers, medical societies, and others. Materials and information …