Pneumonia Outcomes with Bactericidal Vs Bacteriostatic Antibiotics

Pavankumar Kamat


January 21, 2022


  • In a meta-analysis, bactericidal antibiotics failed to show any significant difference in clinical cure rates, mortality, microbiological eradication, and treatment failure or relapse rates compared with bacteriostatic antibiotics in the treatment of pneumonia.

Why this matters

  • Findings suggest that differences in efficacy between antibiotics should be considered on an individual basis rather than classifying them as bactericidal or bacteriostatic antibiotics.

Study design

  • Researchers at the University College London conducted a meta-analysis of 43 randomised controlled trials (RCTs) involving 10,752 patients with pneumonia.

  • Primary outcome: clinical cure rate.

  • Secondary outcomes: all-cause mortality, microbiological eradication, treatment failure, and relapse rates.

  • Funding: None.

Key results

  • No significant difference was seen between bactericidal and bacteriostatic antibiotic treatments in (risk ratio; 95% CI):

    • clinical cure rate (1.02; 0.99 to 1.05; P=0.13);

    • all-cause mortality (1.07; 0.81 to 1.42; P=0.62; I2, 57%);

    • microbiological eradication (1.00; 0.97 to 1.03; P=0.98);

    • treatment failure (0.96; 0.83 to 1.11; P=0.60); and

    • relapse rate (1.15; 0.50 to 2.63; P=0.75).


  • Microbiological definition of bactericidal and bacteriostatic was not strongly supported by either pre-clinical or clinical evidence.

Saleem N, Ryckaert F, Chandos Snow TA, Satta G, Singer M, Arulkumaran N. Mortality and clinical cure rates for pneumonia: A systematic review, meta-analysis, and trial sequential analysis of randomized control trials comparing bactericidal and bacteriostatic antibiotic treatments. Clin Microbiol Infect. 2022 Jan 13 [Epub ahead of print]. doi: 10.1016/j.cmi.2021.12.021. PMID: 35033654 View abstract.


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