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Comparative effects of amoxycillin and ampicillin in the treatment of experimental mouse infections
Abstract:
Amoxycillin was significantly more active than ampicillin in the treatment of intraperitoneal mouse infections when administered by oral and parenteral routes, although the causal bacteria were equally susceptible in vitro to the two penicillins. Amoxycillin produced higher antibiotic blood concentrations in mice than ampicillin after oral administration, and this was a possible explanation for the superior oral activity of amoxycillin. In contrast, antibiotic blood concentrations were the same for both compounds after subcutaneous injection, but it was demonstrated that amoxycillin was more effective than ampicillin by this route in reducing bacterial counts in the peritoneal cavity and in the blood of mice infected with Escherichia coli. Amoxycillin was also significantly more active than ampicillin in the treatment of infection by intraperitoneal dosing as a result of greater bactericidal activity in infected mice together with the production of higher antibiotic blood levels. The results of these studies on the effects of parental treatment of experimental infections with the two penicillins show that the superior chemotherapeutic activity of amoxycillin was associated with the greater bactericidal activity of amoxycillin in vivo and with differences in the distribution of the two penicillins in the infected animal.
Insights
Amoxycillin demonstrated superior activity compared to ampicillin in treating mouse infections, both orally and parenterally. This enhanced efficacy is linked to amoxycillin
Area of Science:
- Pharmacology
- Infectious Diseases
- Microbiology
Background:
- Ampicillin and amoxycillin are both beta-lactam antibiotics used to treat bacterial infections.
- In vitro studies show similar susceptibility of bacteria to both ampicillin and amoxycillin.
- Differences in in vivo efficacy between amoxycillin and ampicillin warrant further investigation.
Purpose of the Study:
- To compare the in vivo efficacy of amoxycillin and ampicillin in treating intraperitoneal mouse infections.
- To investigate the pharmacokinetic and pharmacodynamic factors contributing to potential differences in efficacy.
- To evaluate the bactericidal activity of amoxycillin versus ampicillin in infected mice.
Main Methods:
- Experimental intraperitoneal infections were established in mice using relevant bacterial pathogens.
- Amoxycillin and ampicillin were administered via oral and parenteral (subcutaneous) routes.
- Antibiotic blood concentrations, bacterial counts in peritoneal cavity and blood, and survival rates were monitored.
- In vitro susceptibility testing was performed to compare bacterial sensitivity to both penicillins.
Main Results:
- Amoxycillin exhibited significantly greater therapeutic activity than ampicillin across both oral and parenteral administration routes.
- Oral amoxycillin led to higher antibiotic blood concentrations compared to oral ampicillin, explaining its superior oral efficacy.
- Despite similar blood levels after subcutaneous injection, amoxycillin demonstrated greater reduction in bacterial load in vivo.
- Amoxycillin showed enhanced in vivo bactericidal activity and favorable distribution in infected tissues compared to ampicillin.
Conclusions:
- Amoxycillin possesses superior chemotherapeutic activity over ampicillin in treating experimental intraperitoneal infections in mice.
- The enhanced in vivo efficacy of amoxycillin is attributed to its greater bactericidal activity and distinct pharmacokinetic/pharmacodynamic properties.
- These findings support amoxycillin as a more effective therapeutic agent than ampicillin in this infection model.