Subcutaneous staphylococcal infections in mice: the influence of antibiotics on staphylococcal extracellular products.

Using a mouse subcutaneous abscess model the effect of subinhibitory concentrations of antibiotics upon alpha-hemolysin, nuclease, lipase and esterase production was investigated. Infected mice treated with erythromycin (10 mg/kg), chloramphenicol (10 mg/kg) and fucidin (5 mg/kg) were compared with those given lincomycin (10 mg/kg) and clindamycin (5 mg/kg). In reference to the first three drugs, early blanching occurred at the inoculation site and necrosis appeared within 18 h, whereas wit the other two agents, lesion progressed more slowly with a slight induration only at the site of injection becoming apparent after 24 h. Neither alpha-hemolysin nor nuclease was elaborated in the lesion of mice treated with lincomycin and clindamycin. Histological examinations of skin of mice treated with the latter antibiotics revealed a localized abscess with little or no spreading of the bacteria as compared to untreated mice and to mice treated with the other antibiotics. Evidence is presented which suggests significant involvement of the extracellular products in the pathogenesis of staphylococcal infection.