Algorithm Shortens Duration of Treatment in Uncomplicated Staphylococcal Bacteremia

Staphylococci pathogens are commonly identified in various types of onset bloodstream infections. Despite the prevalence of these pathogens, clinicians do not have access to guidelines based on evidence-based studies; therefore, it is typical for there to be a variety of treatment practices.

Using prolonged courses of antibiotics to treat complicated staphylococcal bacteremia has led to overuse of antibiotics and a higher likelihood for adverse events. Conversely, using shorter courses of therapy in patients with complicated infections creates a higher risk for relapse, morbidity, and mortality.

In a new study from Duke Health, investigators were able to shorten the duration of antibiotics for patients with uncomplicated infections by using an algorithm to determine the duration of the course of treatment.

"Any reductions in the use of antibiotics to treat these infections would be a significant benefit in our effort to fight antibiotic resistance, particularly when these measures can be undertaken without harm to patients," Thomas L. Holland, MD, assistant professor of medicine at Duke and lead author of the study, said in a recent statement.

In the study, published in the Journal of the American Medical Association, the investigators set out to determine if the algorithm could have an effect on the occurrence of serious adverse events in and clinical success of patients with staphylococcal bacteremia.

From April 2011 to March 2017, the randomized trial enrolled 509 adults with staphylococcal bacteremia from 16 medical centers in the United States and Spain. Patients with complicated infections at the time of enrollment were excluded from this trial

The participants were randomly assigned to be placed in 1 of 2 treatment groups—the algorithm-based therapy group (255 participants) or the usual practice group (254).

In the algorithm group, the diagnostic evaluation, eligible antibiotics, and duration of therapy were predefined. In the usual practice group, clinicians were unrestricted when deciding which antibiotics to use, the duration of treatment, and other aspects of clinical care.

Among the 509 participants, 480 completed the trial; clinical success was documented in 209 of the 255 participants assigned to algorithm-based therapy and 207 of the 254 participants randomized to usual practice (82.0% vs 81.5%; difference, 0.5% [1-sided 97.5% CI, −6.2% to ∞]).

Serious adverse events were reported in 32.5% of algorithm-based therapy patients and 28.3% of usual practice patients (difference, 4.2% [95% CI, −3.8% to 12.2%]).

The mean duration of therapy was 4.4 days for algorithm-based therapy vs 6.2 days for usual practice (difference, −1.8 days [95% CI, −3.1 to −0.6]).

Overall, use of the algorithm for testing and treatment was found to be noninferior to usual care as the rate of clinical success in patients with staphylococcal bacteremia was comparable. The rate of serious adverse events did not produce a significant difference, but the investigators indicate that the interpretation is limited due to wide confidence intervals.

"The big point of this study is doing the same with less," senior author Vance G. Fowler, MD, professor of medicine at Duke and member of the Duke Clinical Research Institute, said in the statement. "If we are able to have the same outcomes but use less antibiotics, that has tremendous benefit at all levels of care."

A limitation of the study is that it was designed to determine optimal treatment duration for a patient with staphylococcal bacteremia with no evidence of metastatic infection, which limited the study to not include participants with complicated bacteremia at the time of enrollment.

Future research will continue to assess the utility of the algorithm, according to the investigators.