Group C Streptococcal Bacteremia: Analysis of 88 Cases

164

119

Twelve strains (the largest number ever reported) of group C and G 1 streptococci (GCS and GGS, respectively) that caused streptococcal toxic shock syndrome (STSS) were collected and characterized. Eleven strains were identified as Streptococcus dysgalactiae subsp. equisimilis, and one strain was identified as Streptococcus equi subsp. zooepidemicus. We found that it was the first reported case of STSS caused by S. equi subsp. zooepidemicus. Cluster analysis according to the 16S rRNA gene (rDNA) sequences revealed that the S. dysgalactiae strains belonged to clusters I and II, both of which were closely related. The emm types and the restriction patterns of chromosomal DNA measured by pulsed-field gel electrophoresis were highly variable in these strains except BL2719 and N1434. The 16S rDNA sequences and other characteristics of these two strains were indistinguishable, suggesting the clonal dissemination of this particular S. dysgalactiae strain in Japan. As the involvement of superantigens in the pathogenesis of group A streptococcus-related STSS has been suggested, we tried to detect known streptococcal superantigens in GCS and GGS strains. However, only the spegg gene was detected in seven S. dysgalactiae strains, with none of the other superantigen genes being detected in any of the strains. However, the sagA gene was detected in all of the strains except Tokyo1291. In the present study no apparent factor(s) responsible for the pathogenesis of STSS was identified, although close genetic relationships of GCS and GGS strains involved in this disease were suggested.

Section: Discussionsupporting

confidence: 61%

Characterization of Group C and G Streptococcal Strains That Cause Streptococcal Toxic Shock Syndrome

Hashikawa

Iinuma

Furushita³

et al. 2004

164

119

“…However, more recent studies revealed that S. dysgalactiae subsp. equisimilis overlaps with the infection spectrum of S. pyogenes, including localized infections such as tonsillitis and superficial skin infections (2,12,16,51) and severe invasive infections such as arthritis, osteomy-elitis, pleuropneumonia, peritonitis, intra-abdominal and epidural abscesses, meningitis, endocarditis, puerperal septicemia, neonatal infections, necrotizing fasciitis, myositis, and streptococcal toxic shock syndrome, as well as the nonsuppurative sequelae and rheumatic fever (2,4,9,12,13,26,27,(36)(37)(38)44). A proportional increase in human infections caused by S. dysgalactiae subsp.…”

mentioning

confidence: 99%

Delineation of Streptococcus dysgalactiae, Its Subspecies, and Its Clinical and Phylogenetic Relationship to Streptococcus pyogenes

Jensen

Kilian

2012

The taxonomic status and structure of Streptococcus dysgalactiae have been the object of much confusion. Bacteria belonging to this species are usually referred to as Lancefield group C or group G streptococci in clinical settings in spite of the fact that these terms lack precision and prevent recognition of the exact clinical relevance of these bacteria. The purpose of this study was to develop an improved basis for delineation and identification of the individual species of the pyogenic group of streptococci in the clinical microbiology laboratory, with a special focus on S. dysgalactiae. We critically reexamined the genetic relationships of the species S. dysgalactiae, Streptococcus pyogenes, Streptococcus canis, and Streptococcus equi, which may share Lancefield group antigens, by phylogenetic reconstruction based on multilocus sequence analysis (MLSA) and 16S rRNA gene sequences and by emm typing combined with phenotypic characterization. Analysis of concatenated sequences of seven genes previously used for examination of viridans streptococci distinguished robust and coherent clusters. S. dysgalactiae consists of two separate clusters consistent with the two recognized subspecies dysgalactiae and equisimilis. Both taxa share alleles with S. pyogenes in several housekeeping genes, which invalidates identification based on single-locus sequencing. S. dysgalactiae, S. canis, and S. pyogenes constitute a closely related branch within the genus Streptococcus indicative of recent descent from a common ancestor, while S. equi is highly divergent from other species of the pyogenic group streptococci. The results provide an improved basis for identification of clinically important pyogenic group streptococci and explain the overlapping spectrum of infections caused by the species associated with humans.

“…Although both GGS and GCS are part of the normal human flora (9), they have also been identified as causative agents of infections of the respiratory tract (29), infections of the skin and soft tissue, and life threatening infections such as endocarditis, bacteremia, and meningitis, frequently with a poor prognosis (3,9). More recently, an increasing number of reports described the association with streptococcal syndromes typically caused by Streptococcus pyogenes (Lancefield group A streptococcus [GAS]), such as streptococcal toxic shock syndrome (STSS) (16,19) and acute rheumatic fever (15).…”

mentioning

confidence: 99%

Clonal Relationships between Invasive and Noninvasive Lancefield Group C and G Streptococci and emm -Specific Differences in Invasiveness

Pinho¹,

Melo‐Cristino²,

Ramírez³

2006

Lancefield group G and group C streptococci (GGS and GCS, respectively) are pathogens responsible for a number of life-threatening infections. A collection of 116 recent (1998 to 2004) invasive (n ‫؍‬ 28) and noninvasive (n ‫؍‬ 88) GGS and GCS clinical isolates from Portugal were characterized. All isolates were identified as Streptococcus dysgalactiae subsp. equisimilis and characterized by emm typing and DNA macrorestriction profiling using pulsed-field gel electrophoresis (PFGE). emm typing revealed the presence of 22 distinct types, including 3 novel types. PFGE identified 14 clones with more than two isolates, but over half of the isolates were concentrated in 3 large clones. Individual clones and emm types showed a low level of association, since the majority of the clones included more than one emm type and the same emm type was found among diverse genetic backgrounds. Two emm types, stg2078 and stg10, were significantly more frequent among invasive isolates, and another two, stg6792 and stg166b, were present only in noninvasive isolates, suggesting a correlation between emm type and invasive disease potential.