Antibiotic resistance in long-term acute care hospitals: the perfect storm

Abstract

Objective: To examine bacterial antibiotic resistance and antibiotic use patterns in long-term acute care hospitals (LTACHs) and to evaluate effects of antibiotic use and other hospital-level variables on the prevalence of antibiotic resistance.

Design: Multihospital ecologic study.

Methods: Antibiograms, antibiotic purchasing data, and demographic variables from 2002 and 2003 were obtained from 45 LTACHs. Multivariable regression models were constructed, controlling for other hospital-level variables, to evaluate the effects of antibiotic use on resistance for selected pathogens. Results of active surveillance in 2003 at one LTACH were available.

Results: Among LTACHs, median prevalences of resistance for several antimicrobial-organism pairs were greater than the 90th percentile value for National Nosocomial Infections Surveillance system (NNIS) medical intensive care units (ICUs). The median prevalence of methicillin resistance among Staphylococcus aureus isolates was 84%. More than 60% of patients in one LTACH were infected or colonized with methicillin-resistant S. aureus and/or vancomycin-resistant Enterococcus at the time of admission. Antibiotic consumption in LTACHs was comparable to consumption in NNIS medical ICUs. In multivariable logistic regression modeling, the only significant association between antibiotic use and the prevalence of antibiotic resistance was for carbapenems and imipenem resistance among Pseudomonas aeruginosa isolates (odds ratio, 11.88 [95% confidence interval, 1.42-99.13]; P=.02).

Conclusions: The prevalence of antibiotic resistance among bacteria recovered from patients in LTACHs is extremely high. Although antibiotic use in LTACHs likely contributes to resistance prevalence for some antimicrobial-organism pairs, for the majority of such pairs, other variables, such as prior colonization with and horizontal transmission of antimicrobial-resistant pathogens, may be more important determinants. Further research on antibiotic resistance in LTACHs is needed, particularly with respect to determining optimal infection control practices in this environment.