A before-after study of multi-resistance and cost of selective decontamination of the digestive tract

We compared standard antibiotic use with an antibiotic policy based on selective decontamination of the digestive tract (SDD) for cost and microbiology.

A 2-year before-after observational study was performed in an 11-bed, mixed medical and surgical intensive care unit (ICU). We included all consecutive patients admitted to the ICU 1 year before and 1 year after institution of SDD (patients admitted within the 2-month SDD run-in period were excluded from analysis). In the year before SDD, 513 patients were treated in the ICU (mean APACHE II 19.5), compared to 529 in the year with SDD (mean APACHE II 19.4).

The duration of mechanical ventilation was shorter in the SDD-treated patients (median 3, interquartile range [IQR] 2-7 days vs median 4 days, IQR 2-10, p = 0.03). The total of ICU variable costs, microbiological costs and antibiotic costs were equal in both episodes: euro 1,171 versus euro 1,168 per patient). Aerobic gram-negative bacilli (AGNB) and multiresistant AGNB were found less frequently in SDD-treated patients, RR 0.37 (95% CI 0.33-0.42) and RR 0.28 (95% CI 0.19-0.42). Multi-resistant AGNB in tracheal secretions and urine more than 72 hours after admission were completely absent in SDD-treated patients.

The overall cost per patient treated during an antibiotic policy including SDD was equal to a policy supporting standard antibiotic care. In addition, duration of ventilation decreased and a trend was shown towards a decreased Length of ICU and hospital stay. Less frequently, cultures from organ sites containing AGNB were found during SDD and the number of multi-resistant strains was significantly reduced at organ sites, in particular trachea and urine. Fewer patients were colonized with multi-resistant AGNB but these numbers did not reach statistical significance.