Bacteriological aspects of selective decontamination of the digestive tract as a method of infection prevention in granulocytopenic patients

Abstract

We describe the bacteriological results of a controlled clinical trial of selective decontamination of the digestive tract as a method of infection prevention in granulocytopenic patients. Selective elimination of Enterobacteriaceae and Pseudomonadaceae species was accomplished by the oral administration of nalidixic acid, co-trimoxazole, or polymyxin. Yeasts were eliminated selectively by amphotericin B or nystatin treatment. The drugs used in this study were chosen because of their capacities to selectively eliminate gram-negative rods and yeast without affecting the anaerobic part of the gut flora which is responsible for colonization resistance. Compared with the control group, the selectively decontaminated patients had significantly fewer (P less than 0.0005) gram-negative rods or yeasts or both in their throat swab cultures and in their feces. This reduction may explain the clinical effectiveness of selective decontamination.

The effect of selective decontamination of the digestive tract with the addition of systemic cefotaxime on the aerobic faecal flora of mice

“…Faecal enterococci have been used as an indicator of an intact anaerobic flora and hence of CR in mice (van der Waaij & Berghuis, 1974) and in humans (Sleijfer et al 1980;de Vries-Hospers et al 1981) as enterococci are resistant to the antibiotics used in SDD and are simpler to estimate than the intestinal anaerobic flora. If, as this study suggests, the addition of Ctx suppresses lactobacilli and thus allows overgrowth by the enterococcal population, monitoring of the latter as indicators of anaerobic flora and hence of CR may be inappropriate.…”

Selective decontamination of the digestive tract by pipemidic acid

“…Only a limited number of antimicrobial agents, such as co-trimoxazole, polymyxin B, tobramycin, and nalidixic acid, can both eliminate the potential aerobic pathogens and preserve colonization resistance (2,11). However, these drugs have disadvantages.…”

Prevention of Bacterial Resistance in Urinary Tract Infections

“…Thus, elim ination of these potential pathogens by the administration of oral antibiotics to decrease the frequency of infection has been suggested [19], Anaerobic bacteria, the predom inant normal fecal flora, rarely cause infections in granulo cytopenic patients and are thought to have a beneficial effect in preventing or retarding aerobic gram-negative infections [19], This concept is known as selective decon tamination or colonization resistance.…”