Topical antibiotic prophylaxis for adults receiving mechanical ventilation

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Plain language summary

Review question

We aimed to assess the effect of two topical antibiotic regimens (selective digestive decontamination (SDD) and selective oropharyngeal decontamination (SOD)) in preventing deaths and respiratory infections in patients receiving mechanical ventilation for at least 48 hours in intensive care units (ICUs). In SDD, non-absorbable antibiotics are applied to the oropharynx (back third of the tongue, the soft palate, the side and back walls of the throat and tonsils), oesophagus, stomach, and intestine. SOD involves the application of non-absorbable antibiotics to the oropharynx only. These regimens may be given alone or in combination with systemic antibiotics.


Infections acquired in ICUs are important complications of treatment with ventilation (invasive mechanical breathing support) in patients with very severe diseases who require such treatment. Some of these people will die because of these infections. One method that has been evaluated to reduce these complications is to use antibiotics as a preventative measure.

Search date

This review is current to 5 February 2020.

Study characteristics

We included 41 trials involving a total of 11,004 patients mechanically ventilated in ICUs to find out whether giving topical antibiotics, alone or in combination with systemic antibiotics, prevents respiratory tract infections and reduces death. Antibiotics were administered either topically (e.g. antibiotics were applied directly to the oropharynx or to the stomach via a nasogastric tube) or systemically (e.g. intravenously (directly into the patient's vein)).

Study funding sources

Twenty-two studies (52.4%) did not report the funding source; 6 studies (14.3%) were supported by public institutional grants; and 13 studies (30.1%) were totally or partially funded by pharmaceutical companies.

Key results

In patients receiving the combination of topical plus systemic antibiotics, there were fewer deaths (data from 18 studies with 5290 patients) and probably fewer patients with respiratory tract infections (data from 17 studies with 2951 patients) compared to those who received no treatment or placebo, although we cannot exclude the possibility that the systemic component of the treatments contributed to the reduction in deaths. Assuming an illustrative risk of 303 deaths and of 417 cases of respiratory tract infections in 1000 people under mechanical ventilation, we expect 48 fewer death in patients who receive a combination of topical plus systemic antibiotics and 238 fewer cases of respiratory tract infections. When patients who received topical antibiotics only were compared with patients who received no treatment, or when patients who received topical plus systemic antibiotics were compared with patients who received systemic antibiotics alone, the number of deaths was probably similar (data from 22 studies with 4213 patients), although there may be fewer patients with respiratory tract infections in patients who received topical prophylaxis (data from 19 studies; 2698 patients). Adverse events were poorly reported, with limited data.

Certainty of the evidence

We judged the certainty of the evidence as high to moderate for deaths and respiratory tract infections and low to very low for adverse events.