The effect of selective decontamination on antimicrobial resistance in intensive care patients: a systematic review and meta-analysis.

Selective Digestive Decontamination (SDD) and Selective Oropharyngeal Decontamination (SOD) are applied to prevent infections amongst Intensive Care Unit (ICU) patients and have proven to reduce mortality and infection rates. However, concerns about the development of antimicrobial resistance persists, specifically after ICU discharge. The aim of this study was to assess the occurrence of antimicrobial resistance during ICU stay and after ICU discharge in patients who had received SDD, or SOD compared to control, explicitly at individual-patient level. A previous systematic review, which included studies on antimicrobial resistance after SDD or SOD published before 01-02-2012, was updated. All studies analyzing antimicrobial resistance during and after ICU stay, were included. All outcomes related to resistant pathogens, whether detected through colonization or infection, were included. Pooled odds ratios and 95% confidence intervals were calculated using the Mantel-Haenszel method with random effects. Analyses were done separately for SDD and SOD. Twenty-seven studies were included in the meta-analysis on the occurrence of antimicrobial resistance during ICU stay, yielding a protective association in patients receiving SDD; OR 0.73 (95%-CI 0.54;0.98, I2 75%), which consisted of significant heterogeneity. Four studies investigated antimicrobial resistance after ICU discharge, of which two demonstrated protective results and two observed an increase in resistance in patients who had received SDD or SOD. A prospective long-term follow-up study is required to investigate the long-term effect of SDD and SOD on antimicrobial resistance. During ICU stay, SDD was not associated with increased antimicrobial resistance to specific antibiotics, consistent with previous findings, although study heterogeneity was considerable. This current review emphasizes the limited amount of data on the long-term effect of antimicrobial decontamination strategies on antimicrobial resistance, without addressing the population level effects on resistance rates and changes in gut-microbiome. Understanding this long-term effect is essential when deciding whether to implement preventative antibiotics.