Sam Berkman

Streptomycin. IV. Adsorption of Streptomycin by Susceptible and Resistant Bacteria

Summary and Conclusions Studies with Staph, aureus, S. dysentetriae Sonne, and B. cereus indicate that streptomycin is adsorbed by bacterial cells, all or nearly all of the adsorption occurring at the cell surface. There was no demonstrable difference in adsorption between susceptible and resistant strains of these organisms. The affinity of streptomycin for bacterial cells is greatly reduced in the presence of NaCl. Evidence is presented indicating that the persistent action of streptomycin in vivo after the blood level falls below a detectable value is not related to a slow desorption of streptomycin from the adsorbed state on bacterial cells.

Comparative activity of nicotinic acid and nicotinamide as growth factors for microorganisms.

Summary Nicotinic acid and nicotinamide do not always produce equivalent growth-promoting effects upon microörganisms. A series of microörganisms is presented showing a ratio of activity of amide to acid varying from one-tenth to infinity. The last case is represented by certain organisms of the Pasteurella group whose growth and respiration is promoted by nicotinamide, but not by nicotinic acid. A further summary is presented of synthetic abilities of different microörganisms with respect to the entire enzyme-coenzyme complex.

Quantitative response of the dysentery bacillus to nicotinamide and related compounds.

Summary By means of a titration method for estimation of bacterial growth it was found that growth is proportional to the quantity of nicotinamide present. Nicotinamide is more active than an equivalent amount of either pyridine-containing coenzyme. Hydrolysis increases the activity of the latter, indicating that the function of nicotinamide is not based entirely on synthesis to either of the known coenzymes. A method has been developed for determining nicotinamide and related substances in blood. The values obtained are higher if autoclaved blood is used.

Accessory Growth Factor Requirements of Some Members of the Pasteurella Group.

Most members of the Pasteurella group of bacteria develop satisfactorily in meat infusion-peptone media but fail to grow in simpler media made from hydrolyzed purified protein or in synthetic media. The substances in infusions of meat, other tissues or yeast which are needed for growth have not been previously identified. Accordingly we wish to report preliminary results of a study of the accessory growth factor requirements of some members of this group of organisms in which it will be shown that nicotinamide, pantothenic acid and, in some cases, the butyl factor for Clostridia are needed for prompt development.∗ Seventeen typical Pasteurella strains were used. These were stock laboratory cultures which had been secured from different sources. They were isolated originally from hemorrhagic septicemias in various species of animals. The results presented in this report apply only to the typical strains of animal origin and not to other species at times included in this genus. The basal medium consisted of a 0.5% solution of hydrolyzed purified gelatin to which was added a supplement of 8 amino acids, 0.3% glucose, 0.5% NaCl, 0.2% K2HPO4, 0.005% MgSO4 and 0.001% CaCl2. To this was added 1 cc of Hoagland salt mixture per liter of medium. The amino acid supplement consisted of 20 mg each of valine, tyrosine, tryptophane, cystine, methionine and histidine and 15 mg each of serine and threonine per liter. The medium was adjusted to pH 7.0 with N NaOH solution and tubed in 5 cc quantities. The accessory growth factors were sterilized by filtration and added aseptically to the basal medium. In the first tests a mixture of known substances was used on the assumption that perhaps some of them might be required by these organisms.