HOST-PARASITE RELATIONSHIPS AMONG GROUP A STREPTOCOCCI. I. HYALURONIC ACID PRODUCTION BY VIRULENT AND AVIRULENT STRAINS.

Willoughby, Donald S. (University of Minnesota, Minneapolis), Yael Ginzburg, and Dennis W. Watson. Host-parasite relationships among group A streptococci. I. Hyaluronic acid production by virulent and avirulent strains. J. Bacteriol. 87:1452-1456. 1964.-Intradermal passage of group A streptococcal strains in rabbits is an easy and effective technique for selecting organisms capable of producing increased amounts of hyaluronic acid. Glutamine was required for in vitro hyaluronate production, although the requirement varied with the organism tested. The virulent type 18 cells produced maximal amounts of hyaluronic acid in the presence of 0.01% glutamine compared with 0.1% for the more avirulent type 28; after animal passage, the glutamine requirement for type 28 decreased to 0.01%. Organisms selected by animal passage produced small quantities of hyaluronic acid in the absence of an exogenous source of glutamine. Glucose at a concentration of 1% gave the greatest stimulation for hyaluronate formation. Growth studies indicated similar rates of multiplication for types 18 and 28; yet, the rate of hyaluronate production under these conditions was much greater for the more virulent type 18. Because of these observations, it is suggested that the rate of hyaluronate production is a contributing factor in the virulence of type 18.