Effect of selective flora suppression on colonization, infection, and mortality in critically ill patients: a one-year, prospective consecutive study

Abstract

Objective: To study the effect of enterally administered polymyxin E, tobramycin, and amphotericin B (selective flora suppression) on bacterial colonization, infection, resistance, and mortality rate.

Design: Prospective, consecutive crossover controlled study.

Setting: Two surgical ICUs in a university hospital; ICU I with ten beds, ICU II with eight beds.

Patients: Two hundred patients entered the 1-yr trial. Fifty of 111 patients received selective flora suppression during the first 6 months in ICU I (test group), while 61 of 111 patients served as the control group in the following 6 months. In ICU II, 49 of 89 patients received no selective flora suppression in the first 6 months (control group), followed by 40 of 89 patients receiving selective flora suppression during the second 6-month period (test group).

Interventions: The test group got a mixture of nonabsorbable antibiotics (paste and suspension) in the digestive tract. The control group received paste and suspension without antimicrobial agents. All 200 patients received cefotaxime during the first 4 days.

Measurements and main results: With the use of selective flora suppression, colonization with aerobic Gram-negative bacilli was significantly (p less than .01) reduced. There was also a significant reduction in nosocomial bronchopulmonary (ICU I and II; p less than .001) and urinary tract (ICU II; p less than .001) infections. The difference in mortality was not significant. There was no development of resistance against the antibiotics used during the limited period evaluated.

Conclusions: Selective flora suppression is effective in reducing secondary colonization by aerobic Gram-negative bacilli. Reduction of bronchopulmonary and urinary tract infections most likely occurs with colonization prevention.