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 a lo...

OBJECTIVE To examine whether penicillin treatment success for group A beta-hemolytic streptococcal tonsillopharyngitis is influenced by patient age, number of days ill prior to initiation of treatment, number of prior episodes, season, total dosage (milligrams per kilogram), and frequency of administration (2 vs 3 times daily). METHODS Four hundred seventy-eight children, adolescents, and you...

BACKGROUND To investigate the carrier rates of group A beta-hemolytic Streptococci (GAS) in various seasons of the year in the upper respiratory tract of healthy children in day-care centers. METHODS In this descriptive study, a total of 1893 throat swabs obtained from healthy children 1-6 years old in 13 day-care centers were screened for beta-hemolytic Streptococci in Ankara, Turkey, betwee...

The taxonomy of streptococci has undergone major changes during the last two decades. The present classification is based on both phenotypic and genotypic data. Phylogenetic classification of streptococci is based on 16S rRNA sequences [1], and it forms the backbone of the overall classification system of streptococci. Phenotypic properties are also important, especially for clinical microbiolo...

Beta-hemolysin production by group B streptococci (GBS) is speculated to be a major virulence factor of the organism. A virulent, beta-hemolytic group B streptococcus strain was mutagenized with the self-conjugative transposon Tn916 to derive isogenic strains with mutations only in the gene(s) responsible for beta-hemolysin biosynthesis. There was no significant difference between the virulence...