CHARACTERIZATION OF ENTEROCOCCUS BACTERIOPHAGES FROM THE SMALL INTESTINE OF THE RAT

Rogers, C. G. (University of Wisconsin, Madison) and W. B. Sarles. Characterization of enterococcus bacteriophages from the small intestine of the rat. J. Bacteriol. 85:1378-1385. 1963.-Enterococcus bacteriophages were isolated by an enrichment procedure from the contents of the small intestines of Sprague-Dawley white rats. After purification by single-plaque isolation, the phages were maintained in Tryptose broth by propagation on strains of Streptococcus faecalis var. zymogenes of similar intestinal origin. The presence of two phage strains was suggested from host range studies, and confirmed by antiserum neutralization tests, whereby the bacteriophages were placed in two distinct, but serologically related, groups. When the characteristics of one phage from each group were studied, differences were observed in antigenic properties, as shown by the ability to stimulate antibody production in rabbits, and in single-step growth characteristics. At 32 C, the latent period was 21 min, and the burst size was 88 plaque-forming particles (PFP) for phage 1; and 34 min and 147 PFP for phage 2. The bacteriophages were similar in temperature of inactivation, sensitivity to pH, and in rates of adsorption to host cells (K = about 2 x 10(-9) ml/min at 32 C). In electron micrographs, the viruses were characterized by slightly elongated heads and long tails, and resembled one another closely. The dimensions of the phage particles were similar to those reported for other phage-host systems within the genus Streptococcus.