The effects of topical antibiotics on eradication and acquisition of third-generation cephalosporin and carbapenem-resistant Gram-negative bacteria in ICU patients; a post hoc analysis from a multicentre cluster-randomized trial

The aim was to quantify the effects of selective digestive tract decontamination (SDD) consisting of a mouth paste and gastro-enteral suspension, selective oropharyngeal decontamination with a mouth paste (SOD) and 1–2% chlorhexidine (CHX) mouthwash on eradication and acquisition of carriage of third-generation cephalosporin-resistant Enterobacterales (3GCR-E) and carbapenem-resistant Gram-negative bacteria (CR-GNB) in Intensive Care Unit (ICU) patients. This was a nested cohort study within a cluster-randomized cross-over trial in six European countries and 13 ICUs with 8665 patients. Eradication and acquisition during ICU stay of 3GCR-E and CR-GNB were investigated separately in the rectum and respiratory tract for the three interventions and compared with standard care (SC) using Cox-regression competing events analyses. Adjusted cause specific hazard ratios (CSHR) for eradication of rectal carriage for SDD were 1.76 (95% CI 1.31–2.36) for 3GCR-E and 3.17 (95% CI 1.60–6.29) for CR-GNB compared with SC. For the respiratory tract, adjusted CSHR for eradication of 3GCR-E were 1.47 (0.98–2.20) for SDD and 1.38 (0.92–2.06) for SOD compared with SC, and for eradication of CR-GNB these were 0.77 (0.41– 1.45) for SDD and 0.81 (0.44–1.51) for SOD, compared with SC. Adjusted CSHRs for acquisition of rectal carriage during SDD (compared with SC) were 0.51 (0.40–0.64) for 3GCR-E and of 0.56 (0.40–0.78) for CR-GNB. Adjusted CSHRs for acquiring respiratory tract carriage with 3GCR-E compared with SC were 0.38 (0.28–0.50) for SDD and 0.55 (0.42–0.71) for SOD, and for CR-GNB 0.46 (0.33–0.64) during SDD and 0.60 (0.44–0.81) during SOD, respectively. SOD was not associated with eradication or acquisition of 3GCR-E and CR-GNB in the rectum. Among mechanically ventilated ICU patients, SDD was associated with more eradication and less acquisition of 3GCR-E and CR-GNB in the rectum than SC. SDD and SOD were associated with less acquisition of both 3GCR-E and CR-GNB than SC in the respiratory tract.