Related Experiment Videos
Comparative efficacies of ceftriaxone, moxalactam, and ampicillin in experimental Salmonella typhimurium infection
Abstract:
The activities of ceftriaxone, moxalactam, and ampicillin against Salmonella typhimurium LT-2 were compared in culture media at pH 5, 6, 7 and 8 and in mice inoculated intraperitoneally. The minimal inhibitory concentrations for strain LT-2 in Mueller-Hinton broth were 0.03 microgram of ceftriaxone per ml, 0.08 microgram of moxalactam per ml, and 0.4 microgram of ampicillin per ml. A comparison of minimal inhibitory concentrations in buffered broth at pH 5 with those in media at higher pH values showed that ceftriaxone was more acid stable than the other antibiotics. Groups of CF-1 female mice inoculated intraperitoneally with 3 X 10(4) colony-forming units received saline or each drug in fourfold decremental doses by the subcutaneous route every 8 h for 3 days, beginning at 24 h after challenge. The mean log 10 colony-forming units of S. typhimurium per spleen at the end of treatment and the mortality rates at 21 days after inoculation were measured for each treatment group. The mean log 10 colony-forming units per spleen was significantly reduced from that of the saline control by dosages of greater than or equal to 0.06 mg of ceftriaxone per kg, 64 mg of moxalactam per kg, or greater than or equal to 16 mg of ampicillin per kg (P less than 0.05). Mortality rates of infected mice were significantly reduced by dosages of greater than or equal to 1 mg of ceftriaxone per kg or greater than or equal to 64 mg of ampicillin per kg (P less than 0.05), whereas moxalactam in dosages as high as 16 mg/kg did not significantly reduce mortality rate. These results demonstrate the superiority of ceftriaxone to the other tested antibiotics on a weight basis in this model of experimental Salmonella infection.
Insights
Ceftriaxone demonstrated superior efficacy against Salmonella typhimurium infections in mice compared to moxalactam and ampicillin. It showed better acid stability in vitro and significantly reduced bacterial load and mortality in vivo.
Area of Science:
- Microbiology
- Pharmacology
- Infectious Diseases
Background:
- Salmonella typhimurium infections pose a significant public health threat.
- Evaluating antibiotic efficacy in vivo and in vitro is crucial for effective treatment strategies.
Purpose of the Study:
- To compare the in vitro and in vivo activities of ceftriaxone, moxalactam, and ampicillin against Salmonella typhimurium LT-2.
- To assess the stability of these antibiotics in varying pH conditions and their impact on infection outcomes in a murine model.
Main Methods:
- Minimal inhibitory concentrations (MICs) were determined for Salmonella typhimurium LT-2 in Mueller-Hinton broth across different pH levels (5, 6, 7, 8).
- CF-1 female mice were infected intraperitoneally and treated with ceftriaxone, moxalactam, or ampicillin via subcutaneous injection.
- Bacterial load in spleens and 21-day mortality rates were measured to evaluate treatment efficacy.
Main Results:
- Ceftriaxone exhibited the lowest MIC (0.03 µg/ml) and superior acid stability compared to moxalactam and ampicillin.
- Effective reduction in splenic Salmonella typhimurium load was observed with ceftriaxone (≥0.06 mg/kg), moxalactam (64 mg/kg), and ampicillin (≥16 mg/kg).
- Ceftriaxone (≥1 mg/kg) and ampicillin (≥64 mg/kg) significantly reduced mortality, while moxalactam (up to 16 mg/kg) did not.
Conclusions:
- Ceftriaxone is more effective than moxalactam and ampicillin on a weight basis for treating experimental Salmonella typhimurium infections in mice.
- The in vitro acid stability of ceftriaxone correlates with its enhanced in vivo performance.
- Ceftriaxone represents a superior therapeutic option for Salmonella infections compared to the other tested antibiotics.