Rectal colonization with Gram-negative bacteria was associated with respiratory tract colonization and the acquisition of Gram-negative infections in the intensive care unit (ICU), according to the results of a study published in Clinical Infectious Diseases.

To evaluate the effect of rectal colonization status on respiratory tract colonization and ICU-acquired infections, 2066 patients admitted to the ICU receiving selective digestive tract decontamination were evaluated. Rectal and respiratory tract colonization status were analyzed twice weekly, and acquisition of infections was monitored daily.

Documented Gram-negative bacteria in the rectum was observed in 1157 patients (56%) during their ICU stays.

ICU-acquired Gram-negative infection was reported in 124 patients (5%), and Gram-negative bacteremia was reported in 44 patients (2.1%).

Rectal colonization with Gram-negative bacteria was associated with an increased risk for respiratory tract colonization (cause-specific hazard ratio [CSHR] 2.93, 95% CI 2.02- 4.23) as well as ICU-acquired Gram-negative infection (CSHR 3.04, 95% CI 1.99-4.65).

Gram-negative bacteremia was associated with rectal colonization (CSHR 7.37, 95% CI 3.25-16.68) and respiratory tract colonization (CSHR 2.56, 95% CI 1.09-6.03). When both the rectum and respiratory tract were colonized, patients were at the highest risk of bacteremia.

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When Enterobacteriaceae and glucose non-fermenting Gram-negative bacteria were analyzed separately, comparable trends were reported.

The study investigators concluded that “rectal colonization with [gram-negative bacteria] is associated with an increased risk of ICU-acquired [gram-negative bacteria] infection and respiratory tract colonization.”

Reference

Frencken JF, Wittekamp BHJ, Plantinga NL, et al. Associations between enteral colonization with Gram-negative bacteria and ICU-acquired infections and colonization of the respiratory tract [published online September 16, 2017]. Clin Infect Dis. doi:10.1093/cid/cix824