Preventive antibiotics lowered risk for infection in ICUs with low antibiotic resistance

Issue: April 2011

The development of highly resistant bacteremia was 59% less likely to occur in patients treated with selective digestive tract decontamination vs. standard care and 63% less likely than patients assigned selective oropharyngeal decontamination in Dutch intensive care units with low levels of antibiotic resistance, according to findings published in The Lancet Infectious Diseases.

Compared with standard treatment, selective digestive tract decontamination (SDD) reduced the risk for acquired respiratory tract colonization with highly resistant microorganisms by 38%, whereas selective oropharyngeal decontamination (SOD) reduced the risk by 32%.

The open-label, clustered-group, randomized, crossover study included 5,463 patients admitted to the ICU across 13 Dutch hospitals with low rates of antibiotic resistance between May 2004 and July 2006.

The researchers assessed the effectiveness of SOD (topical tobramycin, colistin, and amphotericin B in the oropharynx), SDD (SOD antibiotics in the oropharynx and stomach plus 4 days of cefotaxime IV) and standard treatment for prevention of respiratory tract colonization and bacteremia with highly resistant microorganisms in ICU patients with an expected duration of mechanical ventilation of more than 48 hours or an expected ICU stay of more than 72 hours.

After 3 days, 7% of SDD patients (OR=0.48; 95%CI, 0.38–0.60) and 9% of SOD patients (OR=0.66; 95% CI, 0.53–0.82) acquired bacteremia vs. 13% of patients assigned standard treatment. In addition, only eight patients assigned SDD acquired highly resistant bacteremia microorganisms when compared with 18 patients assigned standard care (OR=0.41; 95% CI, 0.18–0.94) and 20 patients assigned SOD (OR=0.37; 95% CI, 0.16–0.85).

Cultures obtained among patients who remained in the ICU for more than 3 days indicated that 8% of patients assigned SDD (OR=0.58; 95% CI, 0.43–0.78) and 10% of those assigned SOD (OR=0.65; 95% CI, 0.49–0.87) acquired respiratory tract colonization with highly resistant microorganisms vs. 15% of patients assigned standard treatment.

Acquired respiratory tract colonization with gram-negative bacteria that were cefotaxime-resistant and colistin-resistant was lowest among those assigned SDD when compared with standard treatment and SOD.

“Use of topical antibiotics to prevent infections in ICU patients does not automatically lead to more antibiotic resistance,” Anne Marie G.A. de Smet, MD, of Onze Lieve Vrouwe Gasthuis Amsterdam and University Medical Center Utrecht in the Netherlands, told Infectious Disease News. “In countries with low levels of antibiotic resistance it seems beneficial and safe to use. It decreases mortality and seems to reduce antibiotic resistance.”

In an accompanying editorial, Jean-Louis Vincent, PhD, of the department of intensive care, and Frédérique Jacobs, MD, of the department of infectious diseases, both at Erasme Hospital, at the Université Libre de Bruxelles in Belgium, wrote, “…de Smet and colleagues’ study was done in an environment where antimicrobial resistance was scarce to begin with. The ICUs in the study were asked to use minimum amounts of certain antibiotics, including carbapenems, a scenario that would be impossible in many ICUs today…The interesting findings are mitigated by a lack of effect on problematic organisms, the study setting and the length of observation. We believe that the data provided by our Dutch colleagues will not convince the world to use SDD or SOD.” – by Ashley DeNyse

For more information:

de Smet. The Lancet. 2011;doi:10.1016/S1473-3099(11)70035-4.

Vincent JL. The Lancet. 2011;doi:10.1016/S0140-6736(11)60389-9.

Disclosure: Dr. de Smet reports no relevant financial disclosures.

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