Mouse model for evaluation of antibiotic treatment of acute and chronic infections.

A thread model is presented which enables the simultaneous evaluation of bactericidal rate and antibiotic concentration at the site of infection in mice. Ampicillin and netilmicin were tested against both gram-positive and gram-negative bacteria. With the doses tested there was substantial drug penetration into the site of infection immediately after initiation of infection (day 0), whereas the drug penetration on days 2 and 6 of infection was delayed and reduced. On day 0 of infection there was significant bactericidal effect, but little or no effect could be demonstrated on days 2 and 6 of infection, even though drug concentrations close to the MBC values for several drug/bacteria combinations were reached. The model reflects the treatment situations for the acute and the chronic infection and may be of help in evaluating the efficacy of the drug at the site of infection.