Streptococcus anginosus, Streptococcus constellatus and Streptococcus intermedius Clinical Relevance, Hemolytic and Serologic Characteristics

Abstract

A collection of 518 "Streptococcus milleri" isolates recovered from clinical specimens was identified to the species level according to recently established criteria. Streptococcus anginosus was the most frequently isolated species (59.3%), followed by S constellatus (30.3%) and S intermedius (10.4%). One third (34%) of all isolates were /3-hemolytic. The majority of S anginosus isolates were nonhemolytic, carried I.ancefield group F, or were nongroupable. Most of the 5 constellatus isolates were /3-hemolytic, as well as 16.6% of S intermedius strains. Streptococcus anginosus was recovered more often from the genital and urinary tracts and S constellatus was recovered from the thorax. Streptococcus intermedius was mostly found in the head and neck area, but was also isolated from the abdomen and the skin, bone, and soft tissue. Streptococcus intermedius and nonhemolytic isolates were recovered most often from abscess-related specimens. Strains belonging to the "Streptococcus milleri" group form a heterogeneous group within the viridans streptococci. They encompass organisms listed in the 1986 edition of Bergey's Manual 1 as S anginosus, Streptococcus MG, Sconstellatus, Sintermedius, "Smilleri, "and minute /3-hemolytic streptococci of Lancefield groups F and G 2 . Although the name "Streptococcus milleri" is not included in the approved lists of bacterial names, 3 the term remains popular because it conveys clinical significance. It refers to those viridans streptococci that may be associated with abscesses or other purulent infections. 4 Recent molecular studies clarified taxonomic relationships within the "Streptococcus milleri"group and Whiley and coworkers 5 redefined three species: S anginosus, S constellatus and S intermedius. In addition, they developed biochemical tests that allow for phenotypic differentiation between the three species. 6 In this study, we were interested in the clinical relevance of the three species within the "S milleri" group. We retrospectively identified a collection of 518 "S mil- From leri" isolates to the species according to Whiley and coworkers. 6 The collection consisted of mainly consecutive isolates from clinical specimens. We tried to establish possible associations between the distinct species, their anatomic distribution, and the relation with infection and abscesses. In addition, we described the hemolytic and serologic characteristics of the three species. MATERIALS AND METHODSThe streptococci studied were collected over a period of almost 3 years (July 1991-June 1994, and were consecutively recovered from clinical specimens routinely submitted for culture at the microbiological laboratory of the University Hospital of Maastricht (azM), a 600-bed tertiary care center. Streptococci were grown on blood agar base (Oxoid, Basingstoke, UK) containing 5% (v/v) sheep blood and on the same plates supplemented with nalidixic acid (5 mg/L) and polymixin B (10 mg/L). These plates were incubated in a C0 2 -enriched atmosphere and inspected for growth after 1 and 2 days. Blood wa...

Haemolytic activity of the `Streptococcus milleri group' and relationship between haemolysis restricted to human red blood cells and pathogenicity in S. intermedius

“…Most diagnostic laboratories use sheep or horse blood agar to screen for haemolysis and this may explain the paradoxical fact that non-haemolytic SMG strains have been found to be more associated with purulent infections than the â-haemolytic SMG strains [8,9]. Indeed, from the present data, many of the non-(sheep) haemolytic SMG strains encountered in diagnostic practice represented S. intermedius strains that invariably expressed haemolysis against human RBC without affecting animal RBC.…”

“…milleri' strains to be associated with purulent disease more frequently than non-haemolytic strains [6,7], but this association was not found by others [8]. A study of 499 SMG clinical strains consecutively isolated irrespective of their haemolytic behaviour found that non-haemolytic strains were isolated more frequently from abscess-related specimens than â-haemolytic strains [9]. Furthermore, it found that the S. intermedius phenotype was proportionally more associated with infection and abscesses than the S. anginosus and S. constellatus phenotypes.…”

A study of small-colony, β-haemolytic, Lancefield group C streptococci within the anginosus group: description of Streptococcus constellatus subsp. pharyngis subsp. nov., associated with the human throat and pharyngitis

“…Similar conclusions have also been reached by other workers using the filter method for DNA hybridization (Kilpper-Balz et al, 1984). The DNA homology data, together with the phenotypic differentiation of S. anginosus, S. constellatus and S. intermedius (Whiley & Beighton, 1991;Ahmet et al, 1995;Jacobs e f al., 1995) and the strong clinical association patterns for these taxa (Whiley et al, 1992;Jacobs et al, 1995), refute the idea that these constitute a single species. The evidence reported in this paper supports the further subdivision of S. constellatus into two subspecies.…”

“…Collectively, these form part of the flora of the mouth and the female urogenital tract, are isolated from the gastrointestinal tract, and are frequently associated with purulent infections in humans (Whiley et al, 1992;Jacobs et al, 1995). Evidence of further taxonomic heterogeneity within the group has been supported by phenotypic and genotypic criteria that include biochemical and cultural characteristics (Winstanley et al, 1992 ;Bergman et al, 1995), long-chain fatty acid composition (Cookson et al, 1989), pyrolysis mass spectra (Winstanley et al, 1992), DNA hybridization (Whiley & Hardie, 1989;Whiley et al, 1997), and rRNA-based studies (Doitt et al, 1994;Bergman et al, 1995 anginosus were shown to exhibit sufficient heterogeneity to warrant division at both species and subspecies level, although the numbers of strains belonging to these taxa were too few to support any formal taxonomic proposals (Whiley et al, 1997).…”

Intermedilysin Is Essential for the Invasion of Hepatoma HepG2 Cells by Streptococcus intermedius

“…AGS are recognized as opportunistic pathogens that cause purulent infection and abscess formation (6,16,32,(37)(38)(39). Notably, S. intermedius is an important pathogen of humans frequently causing deep-seated infections including abscesses in the brain and liver (38,39 Abstract: Streptococcus intermedius causes endogenous infections leading to abscesses.…”