Short course of antibiotics worked as well as long for Enterobacteriaceae bacteremia

Rates of mortality, recurrent bloodstream infections, and Clostridium difficile infections within 30 days were similar whether patients received eight or 15 days of antibiotics.


For patients with Enterobacteriaceae bloodstream infections, a short course of antibiotics led to similar outcomes as a longer course, a recent study found.

The retrospective cohort study included adult patients from three medical centers who had Enterobacteriaceae bacteremia treated with in vitro active therapy between 2008 and 2014. Patients who had received a short course of therapy (median duration, eight days) were matched 1:1 with those who had received a long course of therapy (median duration, 15 days), resulting in 385 matched pairs. Results were published online by Clinical Infectious Diseases on Oct. 8.

The study's primary outcome was all-cause mortality within 30 days of the end of antibiotic treatment, and it did not differ between the short- and long-course groups. Rates of recurrent bloodstream infections and Clostridium difficile infections within 30 days were also similar between groups. The short course of therapy also showed a slight protective effect against developing multidrug-resistant gram-negative bacteria within 30 days, but this was only a trend, not a statistically significant difference (odds ratio, 0.59; 95% CI, 0.32 to 1.09; P=0.09).

The study authors noted that current Infectious Diseases Society of America guidelines suggest antibiotics for seven to 14 days for such patients but that this recommendation is based on low-grade evidence. Previous research has shown variability in prescribing practices and the need for high-quality evidence to standardize therapy for gram-negative bloodstream infections, the authors said. The current study was limited by its reliance on observational data, but the authors attempted to overcome that problem by using propensity score matching to create comparator groups that were similar in demographics, pre-existing medical conditions, source control measures, and severity of illness.

Based on the results, the authors concluded that a short course of antibiotic therapy yields similar clinical outcomes as longer courses for patients with Enterobacteriaceae bacteremia and that a shorter course may also protect to some extent against multidrug-resistant gram-negative bacteria. The results do not apply to patients with inadequate source control, because few such patients were included in the study, the authors noted.