Distribution and incidence of viridans streptococcal species in routine clinical specimens.

Five hundred consecutive isolates of viridans streptococci were identified to the species level in an effort to determine their distribution and incidence in routine clinical specimens. Viridans streptococci accounted for significant percentages of streptococcal isolates from urine, wounds, body fluids, and blood. The most commonly isolated strains belonged to the Streptococcus milleri, Streptococcus mitis, Streptococcus sanguis I, and Streptococcus sanguis II species. Patient charts were reviewed in order to investigate the possible role as a urinary pathogen of strains belonging to a subgroup of S. milleri. Although these strains frequently are isolated from urine, they appear to play no pathogenic role in urinary tract infections.