Related Experiment Videos
In vitro effect of imipenem on Acinetobacter baumannii
1Institute of Preventive and Clinical Medicine, Bratislava, Slovak Republic.
Abstract:
Imipenem at suprainhibitory concentrations (2x, 4x or 8x MIC) induced postantibiotic effects (PAEs) (suppression of bacterial growth after a short time exposure of bacteria to antimicrobials) against two of three Acinetobacter baumannii strains. The highest concentration tested demonstrated the longest delay of bacterial regrowth (1.7 h (strain 5570) or 3.9 h (strain 6070)). All. A. baumannii strains showed changes in surface hydrophobicity and serum sensitivity after treatment with imipenem. The antibiotic at 8x MIC reduced hydrophobicity of the strains most significantly (from 42.3%-72.0%) as compared to controls (without antibiotic). Susceptibility of the treated bacteria to serum bactericidal activity has also been lowered. Though imipenem suppressed bacterial growth and decreased surface hydrophobicity of the bacteria, it increased survival of bacteria after incubation with serum. These different alterations observed in the studied strains should be taken into account when evaluating the effects of imipenem.
Insights
Imipenem treatment caused delayed bacterial regrowth and altered surface properties in Acinetobacter baumannii. Despite reduced hydrophobicity, bacteria showed increased survival in serum, impacting treatment evaluations.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Acinetobacter baumannii is a significant opportunistic pathogen, often associated with hospital-acquired infections.
- Understanding the sub-lethal effects of antibiotics like imipenem is crucial for effective treatment strategies.
Purpose of the Study:
- To investigate the postantibiotic effects (PAEs) of imipenem on Acinetobacter baumannii.
- To evaluate the impact of imipenem treatment on bacterial surface hydrophobicity and serum sensitivity.
Main Methods:
- Exposure of Acinetobacter baumannii strains to suprainhibitory concentrations of imipenem (2x, 4x, 8x MIC).
- Measurement of postantibiotic effects (PAE) by monitoring bacterial regrowth.
- Assessment of changes in bacterial surface hydrophobicity and susceptibility to serum bactericidal activity.
Main Results:
- Imipenem induced PAEs in two of three Acinetobacter baumannii strains, with longer delays in regrowth at higher concentrations.
- Treatment with imipenem significantly reduced surface hydrophobicity in all tested strains.
- Despite reduced hydrophobicity, imipenem-treated bacteria exhibited increased survival when incubated with serum.
Conclusions:
- Imipenem exhibits complex effects on Acinetobacter baumannii, including growth suppression and alterations in surface characteristics.
- The observed increase in serum survival post-imipenem treatment warrants consideration in clinical settings.
- Further research is needed to fully elucidate the implications of these findings for imipenem efficacy against Acinetobacter baumannii infections.