A shorter course of antibiotic treatment (7-10 days) for uncomplicated gram-negative bloodstream infections, including treatment of urinary tract associated gram-negative bacteremia, appears to be as effective as long-course antibiotic treatment, according to 2 posters presented at IDWeek 2019, held October 2 to October 6, 2019 in Washington, DC.1,2

The 2 single-center retrospective studies were conducted to evaluate the efficacy of using shorter antibiotic courses in the treatment of bacteremia. Go, et al1 compared short (7 to 10 days) with long (11-20 days) course of antibiotics for uncomplicated gram-negative bacteremia. The researchers from the University of Kentucky in Lexington analyzed data from 466 patients (208 in short-course treatment; 258 in long-course treatment).

Although patients in the long-course group had more admissions to the intensive care unit (ICU) compared with the group in the short-course group (52.7% vs 43.3%, respectively; P =.0426), were older (age 57±16.7 vs 53±15.9 years, respectively; P =.0119), had a higher Charlsaon Comorbidity Index (5.7±3.6 vs 4.6±3.6, respectively; P =.0009), and had longer hospital stays (23.2±25.6 vs 15.8±17.5 days, respectively; P =.0002). There was no difference in 30-day mortality between the long-course group and the short-course group (3.9% vs 3.4%, respectively; P =.7701).

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Findings for 30-day mortality were similar in the second study, which evaluated failure rates between short- (7-10 days) vs long- (>10 days) course treatment of urinary tract-associated gram-negative bacteremia.2 Researchers from the University Health System in San Antonio, Texas, analyzed data from 207 patients who received an intravenous or a highly bioavailable oral agent for ≥7 days (45 in short-course treatment and 162 in long-course treatment).

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At baseline, both treatment groups had similar comorbidities, ICU admission, and vasopressor initiation. There was no statistically significant difference in the primary composite endpoint (comprising both 30-day all-cause mortality and 90-day recurrence): 4.4% in short-course treatment vs 6.2% in long-course treatment (P =.66). In addition, there was no difference in secondary outcomes, which included 30-day readmission, 90-day mortality, resistance development within 90 days, and Clostridium difficile-associated diarrhea.

While generalizability to more complicated cases may be limited, findings from these 2 studies add to the body of medical literature and evidence that supports the use of shorter antibiotic durations in gram-negative bacteremia.


1. Go J, Cotner S, Burgess D, et al. Short versus long course of antibiotics for uncomplicated gram-negative bacteremia. Presented at: IDWeek 2019; October 2-6, 2019; Washington, DC. Poster 149.

2. Badwal J, Hand E, Lyons J, Traugott K. Urinary tract associated gram-negative bacteremia: Impact of treatment duration. Presented at: IDWeek 2019; October 2-6, 2019; Washington, DC. Poster 150.