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Oral, gut decontamination does not reduce bloodstream infections in ICU

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October 29, 2018

Results of a randomized clinical trial showed that selective oral or digestive tract decontamination is not associated with reductions in ICU-acquired bloodstream infections caused by multidrug-resistant gram-negative bacteria among patients receiving mechanical ventilation with moderate to high antibiotic resistance prevalence.

“[Selective decontamination of the digestive tract (SDD)] and [selective oropharyngeal decontamination (SOD)] are routinely used in ICUs in the Netherlands, but their use has not been widely adopted in other countries, mainly because of limited efficacy data in settings with higher levels of antibiotic resistance and concern about emergence of antibiotic resistance, although the latter is not supported by meta-analyses,” Bastiaan H. Wittekamp, MD, PhD, of University Medical Center Utrecht in the Netherlands, and colleagues wrote in JAMA.

The researchers evaluated the effects of chlorhexidine 2% mouthwash, SOD using mouth paste with colistin, tobramycin and nystatin, and SDD using the same mouth paste and gastrointestinal suspension with the same antibiotics, on ICU-acquired bloodstream infections and 28-day mortality in ICUs compared with standard care, which included daily chlorhexidine body washes and a hand hygiene improvement program. They conducted the trial in 13 European ICUs where at least 5% of bloodstream infections are caused by extended-spectrum beta-lactamase–producing Enterobacteriaceae.

Eligible patients had anticipated mechanical ventilation of more than 24 hours, were at least 18 years of age and were not pregnant or allergic to any components of the study intervention. After a 6- to 14-month baseline period, each ICU was randomly assigned to three separate 6-month intervention periods during which chlorhexidine, SOD, or SDD were applied four times a day.

The study included 8,665 patients: 2,251 patients in the baseline period, 2,108 in the chlorhexidine period, 2,224 in the SOD period and 2,082 in the SDD period. Overall, 144 patients acquired bloodstream infections caused by multidrug-resistant gram-negative bacteria (154 episodes), totaling 2.1% of the baseline patients, 1.8% of chlorhexidine patients, 1.5% of SOD patients and 1.2% of SDD.

According to Wittekamp and colleagues, the absolute risk reductions compared with baseline were 0.3% (95% CI, –0.6 to 1.1) for chlorhexidine, 0.6% (95% CI, –0.2 to 1.4) for SOD, and 0.8% (95% CI, 0.1-1.6) for SDD. Adjusted HRs during each period compared with baseline were 1.13 (95% CI, 0.68-1.88) for chlorhexidine, 0.89 (95% CI, 0.55-1.45) for SOD, and 0.7 (95% CI, 0.43-1.14) for SDD, they reported.

Study findings showed that the crude mortality risks on day 28 were 31.9% during the baseline period, 32.9% during the chlorhexidine period, 32.4% during the SOD period, and 34.1% during the SDD period. Adjusted ORs for 28-day mortality when compared with baseline were 1.07 (95% CI, 0.86-1.32) for chlorhexidine, 1.05 (95% CI, 0.85-1.29) for SOD, and 1.03 (95% CI, 0.8-1.32) for SDD.

“The study by Wittekamp et al contributes important data to the decades-long debate about the use of decontamination strategies to prevent bloodstream infections and mortality in critically ill patients,” Christina M.J.E. Vandenbroucke-Grauls, MD, PhD, of Amsterdam University Medical Center, and Jos W.M. van der Meer, MD, PhD, of Radboud University Medical Center in the Netherlands, wrote in an accompanying editorial. “It shows no benefits in situations with higher antibiotic resistant patterns that unfortunately still prevail in most ICUs around the world.” – by Erin Michael

Disclosures: Vandenbroucke-Grauls reports participating in the writing of the Dutch Guideline on Selective Decontamination published by the Dutch Working Party on Antibiotic Policy (SWAB), which promotes the use of selective decontamination in Dutch ICUs. Wittekamp reports receiving grants from the European Commission during the conduct of the study. Please see the study for all other authors’ relevant financial disclosures.