Improved recovery of group A beta-hemolytic streptococci with a new selective medium

J. R. Carlson, W. G. Merz, B. E. Hansen, S. Ruth, D. G. Moore

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11 Scopus citations


A new selective group A streptococcus agar (ssA) (BBL Microbiology Systems, Cockeysville, Md.) was evaluated for the recovery and direct plate identification of group A beta-hemolytic streptococci (GABHS) in comparison with sheep blood agar (SBA). A total of 265 GABHS were recovered from 1,116 throat swab specimens on both media, with detection rates of 98.9 and 91.7% for ssA and SBA, respectively. Primary bacitracin disk susceptibility tests were performed on 549 specimens, and presumptive identifications were possible for 81.4% of the GABHS on ssA, as compared with 44.2% on SBA. All of the 120 GABHS recovered from another 567 specimens were identified by a coagglutination method after overnight incubation on ssA, whereas only 70.2% were identified at this interval on SBA. The major advantage of the ssA was the inhibition of normal respiratory flora, permitting improved recovery and rapid identification of GABHS.

Original languageEnglish (US)
Pages (from-to)307-309
Number of pages3
JournalJournal of clinical microbiology
Issue number3
StatePublished - 1985
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology (medical)


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