Host Modification and Restriction with a Mycobacteriophage Isolated from a Pseudolysogenic Mycobacterium chelonei

Abstract

A pseudolysogenic M. chelonei and its phage .vphi.630 are described. Phage .vphi.630 is the 1st mycobacteriophage reported to be resistant to the nonpolar solvents chloroform, dioxane and diethyl ether. The phage had a latent period of 75 min, a rise period of 90 min and a burst size of 51. Evidence is presented for host modification and restriction. Phage .vphi.630A, grown on host strain M. chelonei F-630 Rg, plated on the alternative host M. smegmatis ATCC607 with an efficiency of plating (e.o.p.) of 10-5. Phage .vphi.630B, grown on host M. smegmatis, plated with an e.o.p. of 10-5 on the alternative host F-630 Rg. Phages .vphi.630A and .vphi.630B adsorbed equally well on their alternative hosts and on their indicator host strains. The progeny of plaques from initial platings on the alternative host, when grown in the alternative host, exhibited a marked reduction in e.o.p. on their original host.