Abstract
Alpha-hemolytic streptococci (AHS) were isolated from blood cultures from 100 patients, and species were identified by the Ruoff and Kunz scheme. When isolates were inoculated onto sheep blood agar, all 100 cultures appeared to be pure, with identifications based on colonial morphology and Gram stain. When isolates were subcultured onto mitis salivarius agar (MSA), mixtures of two species of AHS were detected in 10 cultures from patients (10%). These mixed cultures would have been reported as pure cultures of Streptococcus milleri (six cultures), Streptococcus salivarius (three cultures), Streptococcus sanguis I (one culture), with identifications based on biochemical profiles. Cultures on MSA demonstrated S. milleri (six cultures), Streptococcus mitis (five cultures), S. salivarius (three cultures), S. sanguis I (one culture), and S. sanguis II (five cultures). The inability to separate AHS species by colony morphology on sheep blood agar demands that a differential medium such as MSA be routinely used for subculture. Failure to use such a medium may account for some of the confusing biochemical profiles associated with AHS species identification.
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Selected References
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- Facklam R. R. Physiological differentiation of viridans streptococci. J Clin Microbiol. 1977 Feb;5(2):184–201. doi: 10.1128/jcm.5.2.184-201.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hardie J. M., Bowden G. H. Physiological classification of oral viridans streptococci. J Dent Res. 1976 Jan;55:A166–A176. doi: 10.1177/002203457605500108011. [DOI] [PubMed] [Google Scholar]
- Horstmeier C., Washington J. A., 2nd Microbiological study of streptococcal bacteremia. Appl Microbiol. 1973 Oct;26(4):589–591. doi: 10.1128/am.26.4.589-591.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lerner P. I. Meningitis caused by Streptococcus in adults. J Infect Dis. 1975 May;131 (Suppl):S9–16. doi: 10.1093/infdis/131.supplement.s9. [DOI] [PubMed] [Google Scholar]
- Ruoff K. L., Kunz L. J. Identification of viridans streptococci isolated from clinical specimens. J Clin Microbiol. 1982 May;15(5):920–925. doi: 10.1128/jcm.15.5.920-925.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Swenson F. J., Rubin S. J. Clinical significance of viridans streptococci isolated from blood cultures. J Clin Microbiol. 1982 Apr;15(4):725–727. doi: 10.1128/jcm.15.4.725-727.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]