Genetic relationships among the different phenotypes of Streptococcus dysgalactiae strains

Abstract

The species Streptococcus dysgalactiae was proposed to accommodate a heterogeneous group of streptococci associated with infections in animals and human beings. This taxon is now considered t o include animal isolates of ahaemolytic group C streptococci, previously called 5. dysgalactiae; animal and human isolates of P-haemolytic group C streptococci, previously called '5. equisimilis '; P-haemolytic group L strains associated with infections in animals and, rarely, in humans; and P-haemolytic group G strains isolated from humans. DNA-DNA reassociation experiments (hydroxyapatite method) and multilocus enzyme electrophoresis (MEE) were performed on reference strains and clinical isolates to determine the genetic relationships among these different phenotypic categories. DNA-DNA hybridization tests showed that they were related at the species level, despite the phenotypic and host heterogeneity. Both genotypic and phenotypic characterization indicated that 5. dysgalactiae could be separated into two major sub-groups. The first subgroup contained a-haemolytic strains that showed levels o f DNA relatedness with the type strain of 5. dysgalactiae ranging from 84 to 90% and from 82 to 88% under optimal (55 "C) and stringent (70 "C) conditions, respectively. The second sub-group contained p-haemolytic strains showing levels of relatedness ranging from 71 t o 79% (55 "C) and from 62 t o 73% (70 "C). Percentage divergence varied from 0-5 t o 1*0% (a-haemolytic group) and from 2.0 t o 3*5% (P-haemolytic group). A dendrogram based on phenotypic similarity between the enzyme bands produced by MEE showed a Jaccard similarity coefficient of 045 between the subclusters formed by the two sub-groups. The results of phenotypic and genotypic characterization were consistent with a published proposal to divide 5, dysgalactiae into two subspecies, 5. dysgalactiae subsp. dysgalactiae and S. dysgalactiae subsp. equisimilis, with a f e w modifications.

Identification of Isolates ofStreptococcus canisInfecting Humans

“…The species has since been isolated from a variety of other animals including cats, rats, mink, mice, rabbits, and foxes. Studies of human and animal Group G streptococci (GGS) based on whole-cell protein profiles (13) and multilocus enzyme electrophoresis (14) have confirmed that S. canis forms a clear taxonomic group within the pyogenic streptococci. The species appears distinct from the most closely related species that include other pyogenic streptococci associated with humans and animals.…”

Soft tissue infection caused by Streptococcus dysgalactiae subsp. equisimilis possessing group Aantigen: a and review of the literature

“…The SDSE is most often resistant to bacitracin [2, 9,18,19], but there are also reports on strains susceptible to that antibiotic [13,14,18,21,27]. The susceptibility to bacitracin is typical of SDSE strains with a group L antigen [21,27], but susceptible SDSE isolates with a group A antigen have been described as well [13,14].…”

“…The susceptibility to bacitracin is typical of SDSE strains with a group L antigen [21,27], but susceptible SDSE isolates with a group A antigen have been described as well [13,14]. Typically, SDSE strains produce no L-pyrrolidonyl arylamidase, and display a negative result of the Voges-Proskauer test, positive result of β-glucuronidase and negative result of α-and β-galactosidase test [9,18].…”

“…The SDSE can be isolated as normal flora of human skin, nasopharynx, digestive tract and genitourinary system [10,19,27]. Pharyngeal [12,33,[47][48][49] and nasal [31] carrier-state of that pathogen has been reported.…”

“…Typically, SDSE strains produce no L-pyrrolidonyl arylamidase, and display a negative result of the Voges-Proskauer test, positive result of β-glucuronidase and negative result of α-and β-galactosidase test [9,18]. Most of them do not hydrolyze hippurate, except for SDSE strains with group L antigen [21,27].…”