Streptococcus agalactiae or Strep B. streptococci. General characteristics are gram-positive coccid, 2.0um occurring in pairs and short chains, facultative anaerobic, beta hemoysis on blood agar.
Usual reservoirs are humans, cattle, horses, dogs, rabbits, guinea pigs, and mice (Material safety).
Mode of transmission varies by age 10-30% of pregnant women harbor group B step in the genital tract, 1% of their offspring develop symptomatic infection within 6 days of birth: source of infection in older infants, children and adults are not well established (material safety).
Key tests for identification include gram stain of spinal fluid (cocci chains) growth on blood agar, beta hemolysis, bacitracin resistant, catalase negative, group B carbohydrate, and hippurate hydrolyzed (Streptococcus agalactiae).
A vaccine for strep B has not been developed. There is current research on the development of a vaccine of strep b by researchers of the National Institiute of Allergy and Infectious Diseases (NIAID). The vaccine creates a chemical link to a capsule of a tetnas toxiod (Niaid). Treatments include intravenous antibiotics such as penicillin in adults and newborns.
Antibiotics are needed to control or prevent Strep B form being transmitted to a mother's newborn baby at delivery (Group B streptococcal Disuse).
To detect Step B a swap from the vaginal are and anorectal area are grown for 24 hours. Signs of infection are shown from sterile body fluids, such as blood, urine or spinal fluid. Signs of step B can also be seen in X-rays. Early &endash;onset infection in a newborn with step B shows symptoms of mild respiratory distress and needs additional oxygen, prematurity, ruptured membranes and maternal fever. (Group B strep support) Late onset infections symptoms include over 90% have meningitis with septicemia, fever, poor feeding and/or vomiting and impaired consciousness.
Virulence factors include capsule, sialic acid capsule, streptomycin, hemolysin, and inhibition of alternate complement path. and inhibition of opsonophagocytosis.
References:
Group B Streptoccal Disease. 4/30/02. Page 2. http://www.cdc.gov/ncidod/dbmd/diseaseinfo/groupbstrep_g.htm\
NIAID New. 4/30/02. P.1 http://www.niaid.nih.gov/newsroom/gbsvacc.htm
Material Safety Data Sheet-Infectious Disease. 4/23/02. pp.3,4,5. http://www.hc-sc.gc.ca/pphb-dgspsp/msds-ftss/msds145e.html
Streptococcus agalactiae. 4/30/02. p.2 http//www.medionfo.ufl.edu/year2/mmmid/bms5300/bugs/stagal.html
Group B strep Support. 4/30/02p.4, 5.8, 9 www.gbss.org.uk