Studies on Hemolytic Streptococci

Open Access
Publisher Website
Google Scholar
Abstract
The serological Groups A and C may be differentiated by sensitivity to nascent Phage B from other groups of hemolytic streptococci with the exception of Group E, which is not encountered in investigations of pathogenic hemolytic streptococci. This differential study includes 556 strains of hemolytic streptococci of Groups A and C, 409 from human, and 147 from animal sources. It was found that fermentation reactions in trehalose and sorbitol broths afford useful data for the identification of strains of Groups A, C and E. Lactose fermentation is also a useful character for the identification of certain species of Groups A and C. The human strains of Group C and those of Group A are alike in their fermentation reactions in trehalose and sorbitol broths. Of the total of 409 human strains of Groups A and C, 99% fermented trehalose but not sorbitol. Animal strains of Groups A and C are more diverse than human strains in their reactions in trehalose and sorbitol broths. Among the 147 strains of animal origin 32, including the 26 strains of Streptococcus cqui, fermented neither substance; 33, including 10 strains of Group A, behaved like human strains in fermenting trehalose but not sorbitol; and 82 strains fermented sorbitol but not trehalose.[long dash]Group A strains are characterized by ability to ferment trehalose but not sorbitol, and by resistance to Phage B filtrate. The majority of Group A strains ferment lactose; a smaller subgroup differs in failing to ferment lactose. The main subgroup of C strains is characterized by ability to ferment sorbitol and lactose but not trehalose, and by sensitivity to Phage B filtrate. Another important subgroup of C strains {Streptococcus equi) differs from the main group in failure to ferment all 3 test substances. The strains of another subgroup of Group C resemble human strains in their ability to ferment trehalose but not sorbitol and resemble animal strains in their sensitivity to Phage B filtrate. They appear to be equally capable of attacking both man and animals. Therefore in routine testing, Group C strains should not be disregarded as non-pathogenic for man on the basis of serological grouping alone. Their fermentation reactions should also be studied. The 5 mentioned groups include 95% of all human and animal. The remaining 5% of strains of our collection were divided among 5 small groups. It is in the strains of these small unimportant groups that most of the irregularities in the correlation of serological grouping with sensitivity to Phage B filtrate occur.