Withholding selective decontamination of the digestive tract from critically ill patients must now surely be ethically questionable given the vast evidence base

Shibli and colleagues recently commented [1] on the Dutch randomised controlled trial in which selective digestive decontamination (SDD) and selective oropharyngeal decontamination (SOD) were associated with significantly lower odds of death as compared with standard care, with odds ratios of 0.83 (P = 0.02) and 0.86 (P = 0.045), respectively [2]. We disagree with the authors’ conclusion that, because there were similar mortality reductions, SOD may be preferred as this avoids routinely exposing patients to intravenous antibiotics and involves less resistance. Cephalosporin consumption was higher in the SDD group, but defined daily doses of penicillins, carbapenems, quinolones and other antibiotics increased by 31%, 37%, 25% and 15%, respectively, in SOD compared with SDD in the Dutch randomised controlled trial [2]. In citing the monthly point prevalence survey [3] of the Dutch randomised controlled trial, Shibli and colleagues failed to mention that the average prevalence of aerobic Gram-negative bacilli resistant to ceftazidime, tobramycin and ciprofloxacin in the respiratory tract was significantly lower during SDD/SOD than in the pre-intervention and post-intervention periods, and that aerobic Gram-negative bacilli resistance to ciprofloxacin and tobramycin in rectal swabs was significantly reduced during SDD compared with standard care/SOD [2,3]. Finally, two recent meta-analyses evaluated the effectiveness of SDD [4] and of SOD [5]: lower airway infections were significantly reduced by both SDD and SOD, but only SDD was associated with a significant survival benefit. We believe that withholding SDD is now ethically questionable given the vast body of evidence on the technique reducing severe infections and mortality, requiring less antibiotic use, and providing less resistance.