SPREAD OF METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS IN A HOSPITAL AFTER EXPOSURE TO A HEALTH-CARE WORKER WITH CHRONIC SINUSITIS

A dramatic increase in the incidence of methicillin-resistant Staphylo coccus aureus at a teaching hospital was documented to be due to three factors: a hospital-wide outbreak of 32 cases caused by an epidemic s train, an increase in the number of nosocomial cases caused by several other strains, and an increase in the number of patients admitted car rying strains acquired at other institutions. Case patients with the e pidemic strain were significantly more likely than control patients to have had previous exposure to a respiratory therapist (P = .005) who had chronic sinusitis due to the epidemic strain. The plasmid DNA of i solates from the implicated respiratory therapist and affected patient s yielded the same patterns on restriction endonuclease digestion. Imp lementation of general control measures and eradication of the respira tory therapist's sinusitis and nasal carriage terminated the epidemic. Establishing the importance of the infected health care worker by epi demiological methods led to control of the outbreak without the instit ution of wide-scale culture of specimens from personnel and the enviro nment or other expensive and labor-intensive measures.