Streptococcus agalactiae

Streptococcus

a genus of gram-positive, predominantly facultatively anaerobic cocci in the family Streptococcaceae occurring in pairs or chains. It is classifiable in several ways, none of them completely satisfactory in terms of species designation. Sherman's classification was based on tolerance tests. The system used most widely in veterinary bacteriology is Lancefield's grouping based on serological tests.

Another means of differentiating streptococci is on the basis of type of hemolysis produced around colonies grown on sheep blood agar. Alpha (α) is partial hemolysis or greening of the agar. Beta (β) hemolysis is seen as a clear zone and gamma (γ) is no hemolysis. Most of the pathogenic species are β hemolytic.

---

Streptococcus agalactiae

causes mastitis in cattle, goats and sheep, neonatal septicemia and urogenital infections in dogs and cats.

Streptococcus avium, Streptococcus durans, Streptococcus faecalis, Streptococcus faecium and Streptococcus gallinarum

reclassified in the genus enterococcus. Now called Enterococcus avium etc.

Streptococcus bovis

an important organism in the development of lactic acidosis in cattle following carbohydrate engorgement because of its capacity to ferment starch to lactic acid.

Streptococcus canis (canus)

isolated from cases of septicemia and adenitis in puppies and kittens.

Streptococcus dysgalactiae

causes mastitis in cows, ewes and goat does and polyarthritis in lambs.

Streptococcus dysgalactiae subsp. equisimilis

causes suppurative arthritis in piglets and abscesses in lymph nodes of the head and neck of horses. Also a cause of cervicitis in mares. Previously called S. equisimilis.

Streptococcus equi subsp. equi

causes strangles in horses.

Streptococcus equi subsp. zooepidemicus

occurs as a secondary infection in most species, particularly in horses in wounds, as a cause of cervicitis and a secondary infection associated with the viral infections of the upper respiratory tract. A cause of metritis and mastitis in cattle and septicemia in lambs, pigs and poultry. Previously called S. zooepidemicus.

Streptococcus equinus

causes opportunist infections in many species.

Streptococcus parauberis, Streptococcus uberis, Streptococcus viridans

may cause mastitis in cows.

Streptococcus pneumoniae

formerly called Diplococcus pneumoniae; pneumococcus, causes pneumonia in humans, nonhuman primates, guinea pigs and calves and mastitis in cattle, and septicemia and arthritis in cats.

Streptococcus porcinus

causes cervical abscess of pigs.

Streptococcus pyogenes

a cause of lymphangitis in foals and an uncommon cause of bovine mastitis. An important pathogen of humans.

Streptococcus spp. biovar 1

causes disease in cultured finfish.

Streptococcus suis

has at least 35 capsular types many of which can cause streptococcal meningitis and arthritis in pigs. There is geographic variance in the importance of individual serotypes but types 1,2,3,4,7,8 and 11 are common pathogens. Infection with type 2 is particularly common and is a zoonosis as is type 14. Immunity to disease can be engendered by vaccination but is serotype specific.

---

Streptococcus agalactiae

A streptococcus normally found in the GI tract, which may cause UTIs, subacute bacterial endocarditis. See Group A Streptococcus, Group B Streptococcus.