Probiotics versus antibiotic decontamination of the digestive tract: infection and mortality

Selective decontamination of the digestive tract (SDD) has been shown to decrease the infection rate and mortality in intensive care units (ICUs); Lactobacillus plantarum 299/299v plus fibre (LAB) has been used for infection prevention and does not harbour the potential disadvantages of antibiotics. The objective was to assess whether LAB is not inferior to SDD in infection prevention.

Two hundred fifty-four consecutive ICU patients with expected mechanical ventilation ≥ 48 h and/or expected ICU stay ≥ 72 h were assigned to receive SDD: four times daily an oral paste (polymyxin E, gentamicin, amphotericin B), enteral solution (same antibiotics), intravenous cefotaxime (first 4 days) or LAB: two times daily L. plantarum 299/299v with rose-hip.

The primary endpoint was infection rate. A difference <12% between both groups indicated non-inferiority of LAB. The trial was prematurely stopped after a study reporting increased mortality in critically ill pancreatitis patients receiving probiotics. No significant difference in infection rate [31% in the LAB group, 24% in the SDD group (OR 1.68, 95% CI 0.91-3.08; p = 0.10)] was found. ICU mortality was 26% and not significantly different between the LAB and SDD groups. Gram-positive cocci and Pseudomonas aeruginosa were significantly more frequently isolated from surveillance cultures in the SDD group compared to the LAB group (for sputum: 18 vs. 10% and 33 vs. 14%). Significantly more Enterobacteriaceae were found in the LAB group (23 vs. 50%). No increase in antibiotic resistance was found during and after SDD or LAB use.

The trial could not demonstrate the non-inferiority of LAB compared with SDD in infection prevention. Results suggest no increased ICU mortality risk in the LAB group.