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The post-antimicrobial suppressive effect of quinolone agents
Drugs Under Experimental and Clinical Research
|January 1, 1987
Summary
New 4-quinolones exhibit a significant post-antimicrobial effect (PAE), suppressing bacterial growth for 4-8 hours. This effect persists even with resistant bacteria and under conditions where the drugs are less active.
Area of Science:
- Microbiology
- Pharmacology
Background:
- The emergence of antibiotic resistance necessitates the development of novel antimicrobial agents.
- Understanding the post-antimicrobial effect (PAE) is crucial for optimizing antibiotic therapy.
Purpose of the Study:
- To investigate the post-antimicrobial effect (PAE) of novel 4-quinolone antibiotics.
- To assess the duration of PAE against common Gram-negative bacteria.
- To evaluate PAE in different physiological conditions and against resistant strains.
Main Methods:
- The study evaluated six new 4-quinolones: ciprofloxacin, ofloxacin, Cl-934, Ro 23-6240, A-56619, and S-25930.
- Post-antimicrobial effect was assessed against Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, and Pseudomonas aeruginosa.
- Experiments were conducted in Mueller-Hinton broth (pH 7.4) and urine (pH 5.5) with a Mg2+ concentration of 9.5 mM.
Main Results:
- All tested 4-quinolones demonstrated a post-antimicrobial effect (PAE).
- Bacterial growth suppression lasted for 4-8 hours against the studied Gram-negative bacteria.
- A significant PAE was observed even in resistant organisms (MICs > 4 µg/ml) after a 2-hour exposure to 200 µg/ml of 4-quinolones.
Conclusions:
- Novel 4-quinolones possess a notable post-antimicrobial effect, contributing to their therapeutic potential.
- The PAE of these agents is consistent across various bacterial species and environmental conditions.
- The findings suggest that 4-quinolones remain effective in suppressing bacterial growth even against less susceptible strains.