Outer membrane proteins in the characterization of salmonellae of various origins

Outer membrane proteins have been studied in 76 Salmonella strains isolated from various sources and differing in their sensitivity to antibiotics, the presence of R-plasmids and a number of enzymatic properties. The outer membranes have been isolated by the modified method of L. W. Coulton and D. T. F. Wan. The study of the isolated proteins has been carried out by means of gel and disc electrophoresis in polyacrylamide gel with sodium dodecyl sulfate according to K. Weber and M. Osborn. The composition of the proteinograms thus obtained has revealed the presence of essential differences between hospital strains and cultures isolated from animals and from the environment in sporadic infections, as well as between strains belonging to different serovars. The possibility of using the characterization of outer membrane proteins of salmonellae in epidemiological investigations is discussed.     

Toxicity of tobramycin in single and multiple administrations to laboratory animals]

The LD50 of tobramycin sulphate administered intravenously, intraperitoneally, subcutaneously and orally to albino mice was 77 (73--82), 262 (234--294), 560 (500--627) and greater than 10500 mg/kg respectively. With an increase in the rate of intravenous administration tobramycin toxicity increased. When tobramycin sulphate was administered subcutaneously daily in multiple doses equivalent to the daily therapeutic doses from humans (calculated for the body surface) and in the doses 2--3 times higher than the above therapeutic ones, the function of the kidneys, liver and the Preier's reflex did not significantly change. When the doses were 8--10 times higher than the therapeutic ones, an increase in the urea level in the blood serum, disappearance and a decrease in the Preier's reflex were observed. The impairment of the kidney function was accompanied by degenerative changes in the convoluted tubules of the kidneys, ischemia of the renal glomeruli and appearance of protein secretion in their capsule cavities. The picture of the peripheral blood did not suffer significant changes. The studies on the acute and chronic toxicity of tobramycin sulphate prepared at the Institute of New Antibiotics showed that the drug did not differ from the import tobramycin samples.