SURVEILLANCE OF COLONIZATION AND INFECTION WITH STAPHYLOCOCCUS-AUREUSSUSCEPTIBLE OR RESISTANT TO METHICILLIN IN A COMMUNITY SKILLED-NURSING FACILITY

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is an i mportant nosocomial pathogen in acute care hospitals and long-term car e facilities. Few studies have been reported in private skilled nursin g facilities (SNFs) not experiencing outbreaks of infections caused by MRSA. Methods: From a 149-bed SNF with no outbreaks, we report a 1-ye ar prospective surveillance study of S. aureus colonization and infect ion, viith focus On S. aureus phenotypes, both methicillin susceptible (MS) and methicillin resistant (MR). Nasal and stool or rectal screen ing cultures were done on admission, and all patients underwent screen ing on at least a quarterly basis for 1 year. Results: Overall, 35% of patients were colonized at least Once with S. aureus, (72% MS, 25% MR , and 3% mixed phenotypes), 94% of the MRSA were ciprofloxacin resista nt. Nasal colonization with any S. aureus was more frequent, but 13% o f patients had positive results only in rectal specimens. Twenty-one p ercent of the newly admitted and 15% of continuing patients acquired c olonization during their stay in the SNF. Colonization was transient o r persistent, persisted longer in the nares compared with colonization in rectal specimens, and was more stable for methicillin-susceptible S. aureus. Nine percent of patients had development of infection with S. aureus. There was no indication that MRSA colonization led to more infections than methicillin-susceptible S. aureus. Of the 13 infected patients in whom cultures had previously been obtained, seven (54%) ha d been colonized by the same phenotype strains. Conclusions: In this p rivate SNF, endemic S. aureus infections occur at a low frequency, ref lecting a moderate level of colonization with S. aureus. However, a tr end showing gradual increases in frequencies of colonization and infec tion is of concern and suggests that in this SNF, future intervention could become warranted.