Oral β-lactams vs fluoroquinolones and trimethoprim/sulfamethoxazole for step-down therapy for Escherichia coli, Proteus mirabilis, and Klebsiella pneumoniae bacteremia

Purpose. To compare rates of treatment failure for patients with bloodstream infections (BSIs) due to Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis who received oral step-down antibiotic therapy with either a fluoroquinolone (FQ) or trimethoprim/sulfamethoxazole (SXT) to rates for those who received an oral beta-lactam (BL). Methods. This retrospective, multicenter, cohort study included 397 unique adult hospitalized patients with a BSI due to E. coli, K. pneumoniae, or P. mirabilis at 6 hospitals in central Texas between July 11, 2016, and July 11, 2018. The primary outcome was a composite of treatment failure comprising 30-day readmission due to recurrence, 30-day all-cause mortality, and change in oral antibiotic. Secondary outcomes included 90-day development of C/ostridioides difficile infection, 90-day colonization with a multidrug-resistant organism, 90-day all-cause readmission, hospital length of stay, and the individual components of the primary outcome. Results. Of the 397 patients included, 200 received oral step-down therapy with a BL while 197 received an FQ or SXT. Most patients had an infection due to E. coli (82.8%) and a urinary source of infection (85%). Median total duration of therapy was 14 days in both groups. No difference in treatment failure was identified between the groups treated with a BL and FQ/SXT (7% vs 5.8%, P = 0.561). Median hospital length of stay was the only secondary endpoint in which there was an observed difference (6 vs 5 days, P = 0.04). Conclusion. We observed no difference in treatment failure rates for patients receiving an oral BL compared to an oral FQ or SXT for step-down therapy of BSIs due to E. coli, K. pneumoniae, and P. mirabilis.

Automated summary

This study compared the rates of treatment failure for patients with bloodstream infections caused by Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis who received oral step-down antibiotic therapy with either a fluoroquinolone or trimethoprim/sulfamethoxazole to rates for those who received an oral beta-lactam. The results showed no significant difference in treatment failure rates between the two treatment methods.