NEW MODE OF GENETIC TRANSFER IN STREPTOCOCCUS FAECALIS VAR. LIQUEFACIENS.

Raycroft, Ruth E. (The Pennsylvania State University, University Park), and L. N. Zimmerman. New mode of genetic transfer in Streptococcus faecalis var. liquefaciens. J. Bacteriol. 87:799-801. 1964.-When chloramphenicol-resistant mutants are grown in mixed culture with the sensitive wild type of Streptococcus faecalis var. liquefaciens 31, a transfer of chloramphenicol resistance occurs. (The marker is stable through at least five transfers.) The transfer mechanism is not inhibited by deoxyribonuclease, nor is it phage-mediated; genetic transfer is apparently dependent upon cell contact. Although kinetic studies have yet to be completed, preliminary data indicate a high efficiency (2.2 per donor cell in some experiments) of transmission. Two levels of drug resistance, 7 and 50 mug, were transferred; in each case, recipient cells expressed the donor's degree of resistance.