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Comparative efficacy of four antibiotics in anaerobic pulmonary infection. An experimental model in rabbits
Abstract:
The efficacy of cefoxitin, mezlocillin, latamoxef and metronidazole in anaerobic lung infection was studied using a rabbit model. A mixture of Bacteroides fragilis, Peptococcus morbillorum, Eubacterium lentum and Fusobacterium nucleatum was inoculated transtracheally to produce infection within the lung. Mezlocillin was most effective, achieving bacteriologic cure in 5 out of 8 animals. With cefoxitin therapy, 4 out of 8 became bacteriologically sterile. Severe diarrhea with elevated titers of Clostridium difficile toxin was noted in most cefoxitin-treated animals. Latamoxef- and metronidazole-treated animals had apparently healed lesions, but cultures were positive in 6 and 7 out of 8 in each group, respectively. The commonest pathogen isolated in the last two groups was P. morbillorum. The therapeutic superiority of mezlocillin over metronidazole and latamoxef was statistically significant (p less than or equal to 0.05).
Insights
Mezlocillin proved most effective in treating rabbit anaerobic lung infections, achieving bacterial cure in most cases. Cefoxitin also showed efficacy but caused significant side effects like diarrhea.
Area of Science:
- Microbiology
- Pharmacology
- Veterinary Medicine
Background:
- Anaerobic lung infections pose significant therapeutic challenges.
- Understanding antibiotic efficacy against polymicrobial anaerobic infections is crucial.
Purpose of the Study:
- To evaluate and compare the efficacy of cefoxitin, mezlocillin, latamoxef, and metronidazole in a rabbit model of anaerobic lung infection.
Main Methods:
- A rabbit model was established using transtracheal inoculation of a mixture of anaerobic bacteria: Bacteroides fragilis, Peptococcus morbillorum, Eubacterium lentum, and Fusobacterium nucleatum.
- Animals were treated with cefoxitin, mezlocillin, latamoxef, or metronidazole.
- Efficacy was assessed by bacteriologic cure rates and lesion healing.
Main Results:
- Mezlocillin achieved bacteriologic cure in 5/8 animals, demonstrating superior efficacy.
- Cefoxitin cured 4/8 animals but was associated with severe diarrhea and Clostridium difficile toxin.
- Latamoxef and metronidazole showed apparent lesion healing but high rates of persistent infection (6/8 and 7/8, respectively).
- Peptococcus morbillorum was the most common pathogen in latamoxef and metronidazole treated groups.
Conclusions:
- Mezlocillin demonstrated statistically significant therapeutic superiority over metronidazole and latamoxef (p <= 0.05) in this anaerobic lung infection model.
- Cefoxitin exhibited efficacy but carried a risk of significant gastrointestinal side effects.
- Further research into optimal antibiotic strategies for anaerobic lung infections is warranted.