Ceftriaxone versus ampicillin for the treatment of community-acquired pneumonia. A propensity matched cohort study

Ceftriaxone is recommended as first-line antibiotic treatment (with the addition of macrolide) for hospitalised adults with community acquired pneumonia (CAP). Narrower-spectrum β-lactam as ampicillin, may be associated with comparable clinical outcomes, with less emergence of resistant pathogens or Clostridioides difficile infection (CDI). We aimed to examine whether ampicillin and ceftriaxone (with the addition of macrolides for both arms) are comparable for the treatment of hospitalized adults due to CAP.

This was a single center, observational cohort study. We included adult patients who were hospitalized in internal medicine wards due to CAP and were treated with either ceftriaxone or ampicillin with the addition of macrolide. A propensity-score model was used. The primary outcome was 30-day all-cause mortality. A multivariable logistic regression analysis and Kaplan-Meier survival analysis was performed. We performed subgroup analyses for the main outcome based on CURB-65 score and age.

A total of 1586 patients fulfilled the inclusion criteria. There was no difference in 30-day mortality rate in the total cohort (28/233 vs. 208/1353 in ampicillin and ceftriaxone arm, respectively; p = 0.184). In the propensity matched cohort (197 in ampicillin and 394 in ceftriaxone arm), there was no significant difference in 30-day all-cause mortality between treatment groups in multivariable analysis of the main model (OR 0.67, 95% CI, 0.37-1.2; p = 0.189) and Kaplan-Meier survival analysis (p = 0.108). Thirty-day mortality rate was (19/197 vs. 57/394, in ampicillin and ceftriaxone arms, respectively; p = 0.108) Patients who were treated with ampicillin experienced significantly lower rates of CDI (0/197, 0% vs. 8/394, 2%; p = 0.044).

Ampicillin was associated with comparable clinical outcomes in comparison to ceftriaxone for patients who were hospitalized due to CAP. Ampicillin was associated with significantly lower rate of CDI. Results need to be confirmed by more robust study designs.