An epidemiologic study of 100 cases of toxoplasmic uveitis: implications for diagnosis and prevention

An epidemiologic study of 100 patients with active chorioretinitis, positive Sabin-Feldman methylene-blue dye-test, and favourable response to antitoxoplasmic drugs (spiramycin) was undertaken to establish a basis for rapid clinical diagnosis and institution of preventive measures for toxoplasmic uveitis. Eighty-two of the 100 patients, but only 19 of 100 controls, gave positive histories of exposure to likely sources of toxoplasmosis, such as hunting and handling of wild game, ingestion of raw meat, etc. Seventy-six of these 82 patients had positive toxoplasmin skin tests, but all subsequently had positive dye-tests. The important practical conclusion was reached that all cases with active chorioretinitis, positive toxoplasmin skin test, or history of exposure to known reservoirs of toxoplasmosis should be treated immediately, as dye-tests in such cases will almost invariably be positive. This clinical approach greatly improves the visual prognosis of toxoplasmic chorioretinitis, since specific therapy need not be delayed for several weeks until the result of the dye-test is known.

TRANSDUCTION OF RESISTANCE TO SOME MACROLIDE ANTIBIOTICS IN STAPHYLOCOCCUS AUREUS

Pattee , P. A. (Iowa State University, Ames) and J. N. Baldwin . Transduction of resistance to some macrolide antibiotics in Staphylococcus aureus . J. Bacteriol. 84: 1049–1055. 1962.—By use of phage 80 of the International Typing Series, propagated on appropriate strains of Staphylococcus aureus , two related markers controlling resistance to certain macrolide antibiotics (erythromycin, oleandomycin, spiramycin, and carbomycin) were transduced among a variety of strains of S. aureus . Unlike the markers controlling penicillinase production and resistance to chlortetracycline and novobiocin, the determinants of resistance to the macrolide antibiotics were transduced at normal frequencies (at least 300 transductants per 10 9 phage) only to certain of the recipient strains. One of the markers studied appears to control an inducible enzyme system which is specifically induced by sub-inhibitory concentrations of erythromycin and which controls resistance to erythromycin, oleandomycin, spiramycin, and carbomycin. The other marker examined confers resistance to erythromycin, oleandomycin, spiramycin, and carbomycin, and shows no evidence of being dependent upon an inducible mechanism.