Effect of Penicillin on Certain Viruses

Abstract

In view of the wide antibiotic activity of penicillin, it is of interest to learn whether it has any effect on the growth of viruses. The present paper deals with experiments designed to gain information on this subject.

Certain representative viruses were used as follows: Vaccinia BH,1 a strain of vaccine virus derived originally from the New York Board of Health Strain and maintained for several years by rabbit testicular passage; Vaccinia CV II, 1 derived from BH by serial passage in Rivers-Li culture medium now of apparently stable virulence; St. Louis Encephalitis, Hubbard strain, obtained from Dr. Margaret E. Smith, and maintained by serial intracerebral mouse passage; Psittacosis 6 BC, obtained through the courtesy of Dr. J. E. Smadel, maintained by serial yolk sac passages; Meningo-pneumonitis virus, M.P., obtained from Dr. T. Francis, Jr., and maintained by mouse lung and chick embryo yolk sac passage; Equine Encephalomyelitis virus, the Eastern strain, secured through the courtesy of Dr. J. E. Beard, was used in its third chick embryo passage.

Penicillin used was prepared by the Reichel and Abbott Laboratories and was part of a supply allocated to the University Hospitals of Cleveland by the Committee on Therapeutics and Other Agents of the National Research Council. Assays were made by the Oxford cup method using spores of Bacillus subtilis for inoculating the solid medium as suggested by Foster and Woodruff. 2 It was found that a much greater yield of spores could be obtained under conditions of partial desiccation of the culture than in the liquid medium originally proposed. The culture was accordingly seeded on the surface of nutrient agar, and incubated for 7 days. It was then harvested and pasteurized and the spore suspension stored at 4°C. If assays were not carried out immediately, the sample was stored at −15°C. Appropriate controls were always included. It was then harvested and pasteurized and the spore suspension stored at 4°C. If assays were not carried out immediately, the sample was stored at −15°C. Appropriate controls were always included.