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Evaluation of antibacterial activity in experimental meningo-encephalitis in mice
Abstract:
Mice infected intracerebrally (ic) or intraperitoneally (ip) with Pseudomonas aeruginosa were treated subcutaneously with graded doses of five antibiotics all of which displayed anti-pseudomonal activity in vitro. The analysis of MIC, ED50 in the ip infection model (ED50-ip) and that in the ic system (ED50-ic) for each agent showed: gentamicin, the most active agent in vitro, was also active in vivo, with an ED50-ic nearly six-fold higher than ED50-ip; ceftazidime, considerably active both in vitro and in vivo, showed comparable values of ED50 in the two systems; ceftriaxone, also active in vitro, showed limited activity in vivo, its two ED50 values being similar; aztreonam, moderately active both in vitro and in vivo, showed comparable activity in the two infection models; carbenicillin, the least active agent in vitro, gave poor results in vivo, with an ED50-ic 2.6-fold higher than ED50-ip.
Insights
Comparing five antibiotics against Pseudomonas aeruginosa in mouse models, researchers found varying in vivo efficacy. Gentamicin showed strong activity, while ceftazidime and aztreonam demonstrated consistent results across infection types.
Area of Science:
- Pharmacology
- Infectious Diseases
- Microbiology
Background:
- Pseudomonas aeruginosa is a significant opportunistic pathogen.
- Antibiotic resistance in P. aeruginosa necessitates evaluating new treatment strategies.
- Understanding in vitro versus in vivo antibiotic activity is crucial for effective treatment.
Purpose of the Study:
- To compare the in vivo efficacy of five antibiotics against Pseudomonas aeruginosa.
- To evaluate antibiotic performance in two distinct infection models: intracerebral (ic) and intraperitoneal (ip).
- To correlate in vitro antimicrobial activity with in vivo therapeutic outcomes.
Main Methods:
- Mice were infected intracerebrally (ic) or intraperitoneally (ip) with P. aeruginosa.
- Subcutaneous administration of graded doses of five antibiotics with known in vitro anti-pseudomonal activity.
- Determination of Minimum Inhibitory Concentration (MIC) and 50% Effective Dose (ED50) in both ip and ic infection models.
Main Results:
- Gentamicin, highly active in vitro, showed significant in vivo efficacy, with ED50-ic approximately six times higher than ED50-ip.
- Ceftazidime and aztreonam exhibited comparable in vitro and in vivo activity across both infection models.
- Ceftriaxone demonstrated limited in vivo activity despite in vitro efficacy.
- Carbenicillin, least active in vitro, performed poorly in vivo, with ED50-ic 2.6-fold higher than ED50-ip.
Conclusions:
- Antibiotic efficacy against P. aeruginosa varies significantly between in vitro and in vivo models.
- Route of infection (ic vs. ip) influences the required antibiotic dosage for therapeutic effect.
- Ceftazidime and aztreonam represent promising therapeutic options due to their consistent performance in vivo.