Acute Care/Hospitalization

Antibiotic use and diarrhea are factors in hospital room contamination with vancomycin-resistant organisms

The antibiotic vancomycin is often used as a last resort when others have failed, which is why vancomycin-resistant infections can be serious. Yet, a new study found that one-fourth of all patients colonized with vancomycin-resistant enterococci (VRE) contaminated their rooms during their intensive care unit (ICU) stay. Diarrhea, overall antibiotic use, and higher VRE colonization rates in the ICU (ICU colonization pressure) were risk factors for room contamination. For example, higher mean ICU colonization pressure increased by 44 percent the risk of room contamination. Presumably, health care workers carry VRE from colonized to noncolonized patients and their environment.

The resulting room contamination may be one mechanism of increased VRE transmission, explain the researchers. They examined room contamination among 143 VRE-colonized patients during a 14-month study in two ICUs at one hospital. One-fourth of the patients had an associated VRE-positive environmental culture. Not taking any antibiotic during VRE was protective against room contamination. Patients who contaminated their rooms were more likely to have diarrhea than those who did not contaminate their rooms (66 vs. 38 percent) and were more likely to have received antibiotics while VRE colonized (94 vs. 80 percent).

There was no significant difference in room contamination rates between patients taking antianaerobic antibiotics and those taking nonantianaerobic antibotics. However, diarrhea and antibiotic use were strongly confounded, since most of the patients with diarrhea were taking antibiotics that often cause diarrhea. Nevertheless, the data suggest that most of the increased risk of room contamination was the result of antibiotic use.

The authors conclude that, although antibiotic therapy may be life-saving for ICU patients, limiting the use of antibiotics when possible and choosing less diarrheogenic antibiotics when feasible may help to limit room contamination. The study was supported by the Agency for Healthcare Research and Quality (T32 HS00060).

See "Antibiotic exposure and room contamination among patients colonized with vancomycin-resistant enterococci," by Marci Drees, M.D., M.S., David R. Snydman, M.D., F.A.C.P., Christopher H. Schmid, Ph.D., and others, in the August 2008 Infection Control and Hospital Epidemiology 29(8), pp. 709-715.

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