Antibiotic-resistant organisms among long-term care facility residents on admission to an inpatient geriatrics unit: Retrospective and prospective surveillance.

BACKGROUND: There is limited information about antibiotic-resistant organisms in community long-term care facilities (LTCFs). The objective of this study was to obtain data on resistant organisms in residents from community LTCFs admitted to an inpatient acute geriatrics service (AGS).

METHODS: Two studies were performed. In the first study, bacteriology records of all admissions to the AGS for the period from November 1, 1998, through June 30, 2000, were reviewed for resistant organisms (methicillin-resistant Staphylococcus aureus [MRSA], vancomycin-resistant enterococci [VRE], and resistant gram-negative bacilli). In the second study, residents admitted to the AGS during a 2-month period (N = 92 admissions) had surveillance cultures (nares, gastrostomy site, wounds, and urine) for resistant organisms done within 72 hours of admission.

RESULTS: In the retrospective study, there were 727 admissions, of which 437 (60%) had 928 cultures within 72 hours of admission; 590 (64%) cultures grew 1 or more pathogens. Urine (65%) and blood (26%) cultures accounted for 91% of all cultures done. Rates of resistance by culture site were as follows: urine (resistant organism in 16.6% of 373 cultures), blood (6.7% of 60 cultures), wound (52% of 23 cultures), and sputum (40% of 20 cultures). MRSA and enterococci with high-level gentamicin resistance were the most common resistant organisms identified. No VRE were isolated; only 3% of 421 gram-negative isolates were considered resistant strains compared with 19% (P <.001) of gram-positive isolates. In the prospective study, 17% of 92 residents were found to have a resistant organism in 1 or more surveillance cultures; the most common resistant organisms were MRSA and high-level gentamicin-resistant enterococci. Only 1 resident was found to have VRE in a rectal swab culture; resistant gram-negative bacilli also were uncommon.

CONCLUSIONS: Among residents of community LTCFs admitted to an AGS, resistant organisms were identified infrequently (<20% of admissions). MRSA was the most common resistant organism; VRE and resistant gram-negative bacilli were rare. These findings vary from other studies suggesting that there may be geographic variation in the epidemiology of resistant organisms among residents of community LTCFs.