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Species/Subspecies: Streptococcus agalactiae
Etymology: Genus name: twisted (like a chain) cocci (coccus means a grain or a berry and referrs to any spherical microorganism)
Species epithet: from lack of milk.
Significance:  [Very important]   
Taxonomy:
PhylumClassOrderFamilyGenus
FirmicutesBacilliLactobacillalesStreptococcaceaeStreptococcus
Type Strain: ATCC 13813 = CCUG 4208 = NCTC 8181.
Macromorphology (smell):
Streptococcus agalactiae Streptococcus agalactiae Streptococcus agalactiae 
Streptococcus agalactiae Streptococcus agalactiae 
Small (approximately 1 mm in diameter) transluscent colonies after incubation for 24 h at 37°C. Many (but not all) strains give a (clear) zone of beta-hemolysis on blood agar. The hemolysis zone can be very thin or broad.
Micromorphology: Nonmotile cocci (less than 2 µm in diameter) in chains. The chains are often longer if the bacteria originate from a fluid culture.
Gram +/Gram -:
Fig. 16:6. Gram staining of Streptococcus agalactiae, strain 09mas018883. Only the degree of magnification differ between the two pictures. The length of the scale bars is in both pictures equivalent to 5 µm. Date: 2011-04-11. Fig. 16:7. Gram staining of Streptococcus agalactiae, strain VB 006/11.
G+
Metabolism: Facultatively anaerobic
Catalase/Oxidase:-/-
Other Enzymes: Esculinase -, hippuricase +, coagulase -, urease -
Biochemical Tests: Voges-proskauer (+)
Fermentation of carbohydrates:
D-glucoselactosemaltoseL-rhamnosesucrose
+v+?+
L-arabinosecellobioseD-mannitolsalicintrehalose
-?-v+
glycerolinulinraffinoseD-sorbitolstarch
+---?
Other carbohydrates: Amygdalin -, ribose +.
Microbiological tests:
Streptococcus agalactiae 
CAMP test positive.
Spec. Char.:
Special Media:
Streptococcus agalactiae Streptococcus agalactiae Streptococcus agalactiae 
Purple agar with lactose is used to investigate if bacteria can ferment lactose under acid production.

SELMA- or SELMA Plus plates are used for cultivation of milk samples from suspected mastitis cases.

Hosts: Cattle, sheep, goats, camels
Disease (Swedish):Kronisk ljuverinflammation (mastit)
Disease (English):Mastitis
Clinical Picture:
Virulence Factors: Antiphagocytic capsule
Genome Sequence:
Acc-noStrainSize (bp)Genome
NC_004368 NEM316 2 211 485 1c + 0 

16S rRNA Seq.:
Acc-noStrainNumber of NTOperon
AB002479 ATCC 13813T 1 450 

Taxonomy/phylogeny:
 Streptococcus agalactiae
About 100 species have been described within the genus Streptococcus. Many species within the genus Enterococcus have earlier been classified as streptococci and, thus, they are closely related. S. agalactiae is closely related to S. dysgalactiae.
Comment:Belongs to Lancefield's group B streptcocci.
Updated:2017-09-27

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Swedish University of Agricultural Sciences