Y. Carmeli et Kl. Ruoff, REPORT OF CASES OF AND TAXONOMIC CONSIDERATIONS FOR LARGE-COLONY-FORMING LANCEFIELD GROUP-C STREPTOCOCCAL BACTEREMIA, Journal of clinical microbiology, 33(8), 1995, pp. 2114-2117
Traditionally, group C streptococci include four species: Streptococcu
s equisimilis, S. zooepidemicus, S. equi, and S. dysgalactiae, the fir
st three of which are group C beta-hemolytic streptococci (GCBHS), How
ever, many of the beta-hemolytic streptococci carrying Lancefield grou
p C antigen isolated from clinical specimens are S. mulleri, These org
anisms can be differentiated by colony size, We retrospectively collec
ted data concerning large-colony-forming GCBHS bacteremia that occurre
d during a period of 8 years at the Massachusetts General Hospital. A
total of 222 cases of beta-hemolytic streptococcal bacteremia were ide
ntified; data on the Lancefield grouping were available in 192 cases:
45 cases (23.6%) were group A, 96 cases (50%) were group B, 7 cases (3
.6%) were group C (large colony forming), and 44 cases (22.9) were gro
up G. The medical records for cases of large-colony-forming GCBHS bact
eremia were reviewed, In one case, the isolate was thought to be a con
taminant; the other six cases are reported (five males and one female;
mean age, 55 years). All patients had severe underlying conditions, a
nd none had a history of exposure to animals, The clinical syndromes i
ncluded two cases of cellulitis and one case each of endocarditis, myo
cardial infarction complicated by infection, pneumonia, and myofasciit
is, The diagnoses for two patients with endovascular infections were d
elayed, Three of the six patients had fatal outcomes, and other two, a
fter prolonged hospitalization, were transferred to a long-term rehabi
litation center, We concluded that the severe outcomes reflect delay i
n diagnosis and treatment as well as the severity of the underlying di
seases, The taxonomy of GCBHS is discussed, More reports differentiati
ng large- and small-colony-forming GCBHS are needed.