Failure of Aureomycin in the Treatment of Experimental Tuberculosis

Abstract

The failure of streptomycin, p-aminosalicylic acid and the sulfone compounds to prove ideal agents for the treatment of tuberculosis has stimulated the testing of many new agents. Because of the remarkably wide anti-microbial spectrum of aureomycin, it seemed worthwhile to study its effect upon experimental tuberculosis.

Guinea pigs weighing 400 to 500 G each were inoculated subcutaneously with 0.02 mg tubercle bacilli from a recently isolated, virulent, streptomycin-sensitive human strain. After 28 days, the animals were divided into two groups. The 12 animals in Group A were treated with daily subcutaneous injection of 5 mg aureomycin hydrochloride, 6 days a week for 6 weeks. The 11 animals in Group B served as infected, untreated controls.

A third group, Group C, consisted of 6 uninfected guinea pigs given aureomycin in the same dosage as Group A, in order to observe possible toxic effects of the drug.

Animals were autopsied as they died, and those surviving after 6 weeks of treatment or 10 weeks after infection were sacrificed and autopsied.

In Table I, it can be seen that mortality was higher in the treated than in the untreated group. Both treated infected and uninfected groups showed marked weight loss, and one of the uninfected animals died during treatment.

All the infected animals showed widespread tuberculous involvement of the regional lymph nodes surrounding the injection site, the liver, spleen, and lungs. Gross and microscopic examination failed to show any appreciable difference between the treated and untreated animals. Acid fast bacilli were demonstrated in the microscopic sections of tuberculous tissue from the 5 animals which survived the full 6 weeks of treatment, and tubercle bacilli were readily cultured from the lung in one of these animals.

A11 the animals treated with aureomycin showed definite evidence of local drug toxicity.