A short course of antibiotic therapy (SC) demonstrated no difference in 90-day mortality compared with a prolonged course antibiotic therapy (PC) in patients with low-risk methicillin-susceptible Staphylococcus aureus bacteremia, according to the findings of a multicenter, retrospective, pooled cohort study published in Clinical Infectious Diseases.

The investigators recruited 3 cohorts of patients with S aureus bacteremia during the course of more than 2 decades in Copenhagen, Denmark. From January 1, 2009, to December 31, 2018, cohort 1 consisted of 645 patients of whom 166 had SC therapy and 479 had PC therapy. From January 1, 2006, to December 31, 2008, cohort 2 consisted of 219 patients of whom 74 had SC therapy and 145 had PC therapy. From January 1, 1995, to December 31, 2010, cohort 3 consisted of 197 patients of whom 51 had SC therapy and 90 had PC therapy.

SC therapy was defined as 6 to10 days of treatment, and PC therapy was defined as 11 to 16 days of treatment. In cohort 1, relapse was defined as the identification of a deep-seated infection or new S aureus bacteremia occurring within 90 days of completion of antibiotic treatment. The primary outcome of this study was death from any cause within 90 days of completed antibiotic therapy.


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In cohort 1, 32 of 166 (19.3%) patients in the SC group and 91 of 479 (19.0%) patients in the PC group died within 90 days of antibiotic treatment termination. There was no significant difference in the primary outcome between groups in the crude (odds ratio [OR], 1.02; 95% CI, 0.65-1.59) or weighted (OR, 0.85; 95% CI, 0.49-1.41) model.

In cohort 2, 17 of 74 (23.0%) patients in the SC group and 30 of 145 (20.7%) patients in the PC group died within 90 days of antibiotic treatment termination. There was no significant difference in the primary outcome between groups in the crude (OR, 1.14; 95% CI, 0.58-2.24) or weighted (OR, 1.24; 95% CI, 0.60-2.62) model.

In cohort 3, 9 of 51 (17.6%) patients in the SC group and 18 of 90 (20.0%) patients in the PC group died within 90 days of antibiotic treatment termination. There was no significant difference in the primary outcome between groups in the crude (OR, 0.86; 95% CI, 0.35-2.08) or weighted (OR, 1.15; 95% CI, 0.24-4.01) model.

It was noted that the duration of therapy was not associated with a 30-day mortality outcome in a sensitivity analysis (OR, 1.03; 95% CI, 0.60-1.65) of the pooled cohort. Additionally, the study authors mentioned further investigations are needed of the application of SC therapy for methicillin-resistant S aureus bacteremia.

“Exploring the possibility of shortening antimicrobial therapy duration is of importance as it could potentially benefit patients in several ways including reduced risks of adverse events, avoiding microbiome disturbances as well as shortening the length of hospital stay. Moreover, minimizing the use of antibiotics is likely to benefit the general public health in terms of preventing resistance development,” the study authors concluded.

Disclosure: One of the study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of the author’s disclosures.

Reference

Thorlacius-Ussing L, Sandholdt H, Nissen J, et al. Comparable outcomes of short-course and prolonged-course therapy in selected cases of methicillin-susceptible Staphylococcus aureus bacteremia: a pooled cohort study. Clin Infect Dis. Published online March 2, 2021. doi:10.1093/cid/ciab201