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Metabolic Profiling to Determine Bactericidal or Bacteriostatic Effects of New Natural Products using Isothermal Microcalorimetry
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Postantibiotic effect of tigecycline against 14 gram-positive organisms

G A Pankuch1, P C Appelbaum

  • 1Department of Pathology, Hershey Medical Center, PA 17033, USA.

Antimicrobial Agents and Chemotherapy
|December 10, 2008
PubMed

Insights

Tigecycline exhibits significant postantibiotic effects (PAEs) and postantibiotic sub-minimum inhibitory concentration effects (PA-SMEs) against various Gram-positive and Gram-negative bacteria, indicating prolonged suppression of bacterial growth after antibiotic exposure.

Area of Science:

  • Microbiology
  • Pharmacology
  • Infectious Diseases

Background:

  • Tigecycline is a broad-spectrum antibiotic used to treat complex infections.
  • Understanding its postantibiotic effects is crucial for optimizing treatment regimens.

Purpose of the Study:

  • To determine the in vitro postantibiotic effects (PAEs), postantibiotic sub-MIC effects (PA-SMEs), and sub-MIC effects of tigecycline.
  • To evaluate these effects across a panel of 14 Gram-positive and Gram-negative organisms.

Main Methods:

  • In vitro susceptibility testing was performed.
  • Postantibiotic effects (PAEs) were measured by incubating bacteria with tigecycline and then subculturing.
  • Postantibiotic sub-MIC effects (PA-SMEs) were assessed at four times the minimum inhibitory concentration (MIC).

Main Results:

  • Tigecycline demonstrated notable PAEs against Gram-positive bacteria (e.g., Enterococcus: 3.9–6.1 h) and Gram-negative bacteria (e.g., Haemophilus influenzae: 1.1–5.0 h).
  • PA-SMEs were substantial, ranging from 6.7 to >11 h for Gram-positive and 2.3 to >11.3 h for Gram-negative organisms.
  • Variability in effects was observed across different bacterial species.

Conclusions:

  • Tigecycline exhibits significant and prolonged postantibiotic effects, suggesting potential for extended dosing intervals or combination therapies.
  • The observed PAEs and PA-SMEs highlight tigecycline's sustained activity against a range of pathogens.
  • Further clinical studies are warranted to correlate these in vitro findings with clinical outcomes.

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