B2.3 GROUP B,C and G STREPTOCOCCI Flashcards
GROUP B STREPTOCOCCI
Streptococcus agalactiae
have group B–specific antigen, acid-stable
polysaccharide located in cell wall
normal flora of female genital tract and lower
gastrointestinal tract
Streptococcus agalactiae
Streptococcus agalactiae MOT
Endogenous strain
gaining access to sterile site(s) probable
Streptococcus agalactiae MOT normally
Direct contact
Causes infection of fetus during passage through the colonized birth canal and premature rupture of mother’s membrane
VIRULENCE FACTORS of Streptococcus agalactiae
CAPSULE
important virulence factor for S. agalactiae
prevents phagocytosis but is ineffective after
opsonization
CAPSULE
most significant component of the capsule of S. agalactiae
critical virulence determinant
SIALIC ACID
AVIRULENT FACTORS of S. agalactiae
Hemolysin
CAMP factor
Neuraminidase
Dnase
Hyaluronidase
Protease
RELATED INFECTIONS AND DISEASES with S. agalactiae
- NEONATAL SEPSIS and MENINGITIS
- Pneumonia
- Postpartum Infection ENDOMETRITIS
- Osteomyelitis
- UTI
- Puerperal Infection
- Endocarditis (Tricuspid Valve Endocarditis)
- Skin infection
- Important etiologic agent of bovine mastitis
S. agalactiae is the most common etiologic cause of
NEONATAL SEPSIS and
MENINGITIS
Neonatal GBS Diseases
Early-onset infection (<7 days old) causes
pneumonia and sepsis
Neonatal GBS Disease
Late-onset infection n (7 days old - 3 months old) causes
meningitis and
sepsis
Specimen of choice for determining S. agalactiae
Vaginal and Rectal swabs
LABORATORY DIAGNOSIS methods for S. agalactiae
- Culture Medium
- CHRISTIE, ATKINS, AND MUNCH-PETERSEN (CAMP) TES
- HIPPURATE HYDROLYSIS TEST
- SEROTYPING
- Culture Medium methods for S. agalactiae
Blood agar plate
Selective broth
Granada Agar
Types of selective broth for S. agalactiae
a. Lim Broth
b. TransVag broth
c. StrepB Carrot Broth
Blood agar plate results for S. agalactiae
grayish white, mucoid, more translucent to opaque, soft, smooth colonies surrounded by smaller zone of βhemolysis
Lim Broth components for S. agalactiae
Todd-Hewitt broth with Colistin and
Nalidixic acid = TRANSPORT MEDIUM
TransVag broth components for S. agalactiae
Gentamicin and Nalidixic acid
StrepB Carrot Broth method for S. agalactiae
orange or red pigment (6 hours
incubation)
selective agar for vaginal or rectal swabs
yellow to orange colonies produced by S. agalactiae
Granada Agar