Prabhakaran K, Harris EB, Randhawa B; American Society for Microbiology. General Meeting.
Abstr Gen Meet Am Soc Microbiol. 1999 May 30-Jun 3; 99: 645 (abstract no. U-58).
GWL HD Center, Baton Rouge, LA.
Postantibiotic effect (PAE) is an important pharmacodynamic property of antibiotics. Many drugs continue to exert their suppressive effect on the growth of bacteria even after the drug concentrations have fallen below detectable levels. By determing the PAE of drugs, it would be possible to optimize antibiotic use and improve patient outcomes. PAE has been studied in many rapid-growing bacteria, but only limited information is available on PAE of slow-growing organisms like mycobacteria. Beta-Lactam/beta-lactamase-inhibitor combinations have been shown to be effective against mycobacteria, including Mycobacterium tuberculosis H37Rv. Statistically significant correlation has been reported between the viable count method and rapid methods like the Bactec technique and spectrophotometry, for monitoring bacterial growth kinetics. We studied the PAE of ampicillin/sulbactam (Unasym) against 7 species of mycobacteria (M. avium, africanum, bovis, fortuitum, scrofulaceum & tuberculosis H37Ra), spectrophotometrically. Four concentrations (5, 10, 50 & 100 micrograms/ml) of the drug were tested. After exposure of the bacteria to ampicillin/sulbactam, they were washed free of the drug, and allowed to multiply. Probably because the bacteria are slow- growing, longer exposure time (1 week) produced a prolonged PAE of the drug against the mycobacteria; 5x and 10x MIC (50 and 100 micrograms/ml, which are concentrations attainable in vivo) resulted in a PAE of at least 24 h. For a shorter exposure time (2 h), only 100 micrograms/ml was effective. The information on PAE of ampicillin/sulbactam might be of clinical relevance in determining dosage regimens of the drug.
Publication Types:
Keywords:
- Ampicillin
- Anti-Bacterial Agents
- Bacteria
- Enzyme Inhibitors
- Humans
- Microbial Sensitivity Tests
- Mycobacterium
- Sulbactam
- beta-Lactams
- sultamicillin
Other ID:
UI: 102195808
From Meeting Abstracts