In a clinical trial a new pyrrolidonyl-β-naphthylamide (PYR) hydrolysis test was compared with the bacitracin disk susceptibility test for accuracy in the presumptive identification of group A streptococci (GAS). Among 128 isolates of beta-hemolytic streptococci 93 group A isolates were found. The sensitivity of the PYR and bacitracin tests were similar (98.9%), but the bacitracin test had ...

Several presumptive tests were evaluated for their effectiveness in differentiating streptococci. When the tests were combined into a battery and the resulting reactions were interpreted as patterns, the overall presumptive identification rate was at least 97%. We used the hemolytic reaction, susceptibility to bacitracin and sulfamethoxazole plus trimethoprim (1.25 micrograms plus 23.75 microgr...

The lysis of cell walls of hemolytic streptococci by a phage-associated lysin has been described. A method is presented for preparing the lysin from Group C streptococcal phage lysates. Following lysis almost all of the cell wall carbohydrate is recovered in solution. This material has the serological reactivity, physical-chemical properties, and values for nitrogen, rhamnose, and glucosamine s...

The host ranges of bacteriophages for group A, types 1, 6, 12, and 25 and group C streptococci have been determined. The findings indicate that the susceptibility to these phages is primarily a group-specific phenomenon, although it is modified by several factors such as the hyaluronic acid capsule, lysogeny, and possibly the presence of surface proteins. Phage antibody studies indicate that wh...

Broth cultures of hemolytic streptococci derived from patients are capable of rapidly liquefying normal human fibrin clot. The active fibrinolytic principle is also contained in sterile, cell-free filtrates of broth cultures. The degree of activity of filtrates parallels the activity of whole broth cultures sufficiently closely to indicate that large amounts of the fibrinolytic substance are fr...

Serologically reactive dextrans were synthesized from sucrose by 22 of 48 strains of streptococci isolated from the blood of patients with subacute bacterial endocarditis. One strain formed an appreciable amount of levan as well as dextran. Nine strains of group H streptococci from throats formed dextran serologically similar to that formed by the described endocarditis streptococci. Six strain...