Differentiation between Streptococcus gallolyticus strains of human clinical and veterinary origins and Streptococcus bovis strains from the intestinal tracts of ruminants

Abstract

Strains formerly identified as Streptococcus bovis were allotted to two groups by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of whole-cell proteins. Strains from humans with infections, mostly patients with endocarditis, and strains from pigeons with septicemia clustered with the recently described species Streptococcus gallolyticus. The original S. bovis type strain and strains exclusively from ruminants formed the second cluster. The findings indicate that S. gallolyticus is more likely to be involved in human and animal infections than S. bovis. Growth characteristics and several biochemical reactions were found to be useful in the differentiation of S. gallolyticus from S. bovis.

FIG. 1

Dendrogram derived from the unweighted pair group average linkages of correlation coefficients (expressed for convenience as percentages of value) between whole-cell protein patterns of all of the strains examined.

FIG. 2

Electrophoretic protein profiles of a selection of S. bovis and S. gallolyticus strains. Strains LMG 16802T, LMG 14620, and LMG 15477 were isolated from a feral goat, a pigeon septicemia specimen, and human endocarditis specimens, respectively. The molecular weight markers used (indicated in the top and bottom lanes) are (from left to right) as follows: lysozyme, 14,500; trypsin inhibitor, 20,100; trypsinogen, 24,000; carbonic anhydrase, 29,000; glyceraldehyde-3-phosphate dehydrogenase, 36,000; egg albumin, 45,000; and bovine albumin, 66,000.