They are also known as Streptococcus anginosus (according to the Lancefield classification system) or as members of the S. milleri group (according to the European system). Group G streptococci
These streptococci are usually, but not exclusively, beta-hemolytic. Streptococcus dysgalactiae subsp. canis is the predominant subspecies encountered. It is a particularly common GGS in humans, although it is typically found on animals. S. phocae is a GGS subspecies that has been found in marine mammals and marine fish species. In marine mammals it has been mainly associated with meningoencephalitis, sepsis, and endocarditis, but is also associated with many other pathologies. Its environmental reservoir and means of transmission in marine mammals is not well characterized. Group H streptococci
Group H streptococci cause infections in medium-sized canines. Group H streptococci rarely cause  human illness unless a human has direct contact with the mouth of a canine. One of the most common ways this can be spread is human-to-canine, mouth-to-mouth contact. However, the canine may lick the humans hand and infection can be spread, as well. Molecular taxonomy and phylogenetics
Streptococci have been divided into six groups on the basis of their 16S rDNA sequences: S. anginosus, S. gallolyticus, S. mitis, S. mutans, S. pyogenes and S. salivarius. The 16S groups have been confirmed by whole genome sequencing (see figure). The important pathogens S. pneumoniae and S. pyogenes belong to the S. mitis and S. pyogenes groups, respectively, while the causative agent of dental caries, Streptococcus mutans, is basal to the Streptococcus group.
Congenital hereditary corneal dystrophy (CHED) is a form of corneal endothelial dystrophy that presents at birth. CHED was previously subclassified into two subtypes: CHED1 and CHED2. However in 2015, the International Classification of Corneal Dystrophies (IC3D) renamed the condition "CHED1" to become posterior polymorphous corneal dystrophy, and renamed the condition "CHED2" to become, simply, CHED. Consequently, the scope of this article is restricted to the condition currently referred to as CHED

Signs and symptoms
CHED presents congenitally, but has a stationary course. The cornea exhibits a variable degree of clouding: from a diffuse haze, to a "ground glass" appearance, with occasional focal gray spots. The cornea thickens to between two and three times is normal thickness. Rarely, sub-epithelial band keratopathy and elevated intraocular pressure occur. Patients have blurred vision and nystagmus, however it is rare for the condition to be associated with either epiphora or photophobia with this. Genetics
CHED exhibits autosomal recessive inheritance, with 80% of cases linked to mutations in SLC4A11 gene. The SLC4A11 gene encodes solute carrier family 4, sodium borate transporter, member 11. Pathology
Histologically, the Descemets membrane in CHED becomes diffusely thickened and laminated. Multiple layers of basement membrane-like material appear to form on the posterior part of Descemets membrane. The endothelial cells are sparse - they become atrophic and degenerated, with many vacuoles. The corneal stroma becomes severely disorganised; the lamellar arrangement of the fibrils becomes disrupted. Diagnosis
Management
Management of CHED primarily involves corneal transplantation. The age that corneal transplantation is required is variable, however, it is usually necessary fairly early in life.