Natural history of colonization with vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus, and resistant gram-negative bacilli among long-term-care facility residents.
OBJECTIVE
To determine the natural history of colonization with vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA), and resistant gram-negative bacilli among long-term-care facility (LTCF) residents.


METHODS
Observational cohort study.


METHODS
A 355-bed LTCF with a ventilator unit and a subacute unit.


METHODS
Residents with colonization or infection with VRE, MRSA, or resistant gram-negative bacilli housed at the LTCF between December 1, 1999, and February 29, 2000.


METHODS
Cultures of clinical and surveillance sites were performed at regular intervals. Charts were reviewed for clinical characteristics associated with clearance of colonization. Kaplan-Meier curves were constructed to analyze the number of days to clearance of colonization.


RESULTS
Forty-nine residents had 65 episodes of colonization (27 VRE, 30 MRSA, and 8 resistant gram-negative bacilli). Eighteen (28%) of the episodes cleared. The clearance rate was 2.7 episodes per 1,000 person-days. Clearance occurred significantly more often with resistant gram-negative bacilli colonization compared with VRE or MRSA colonization (6 [75%] vs 12 [21%]; P = .007; relative risk, 4.17; 95% confidence interval, 1.26 to 11.8). There was a trend toward longer use of antimicrobial agents among residents with persistent colonization. Infections occurred most frequently with MRSA. The urinary tract was the most common site of infection.


CONCLUSIONS
Among LTCF residents, colonization with resistant gram-negative bacilli is four times more likely to clear than colonization with VRE or MRSA. Performance of surveillance cultures at regular intervals may reduce the need for contact precautions for LTCF residents with resistant gram-negative bacilli colonization.
Pacio
Glenn A
GA
Division of Infectious Diseases, New York Medical College, Valhalla 10595, USA.
Visintainer
Paul
P
Maguire
George
G
Wormser
Gary P
GP
Raffalli
John
J
Montecalvo
Marisa A
MA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003428:Cross Infection; D016983:Enterococcus / Q000187:drug effects* / Q000302:isolation & purification / Q000472:pathogenicity*; D005260:Female; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000472:pathogenicity; D016905:Gram-Negative Bacterial Infections / Q000635:transmission*; D006801:Humans; D008134:Long-Term Care; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D012121:Respiration, Artificial; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000635:transmission*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000472:pathogenicity*; D020713:Vancomycin Resistance