1) Streptococcus agalactiae (Group B Strep) commonly resides in the human vagina, pharynx, and large intestine and can cause severe infections in newborns when transmitted during delivery. Pregnant women are screened and treated if positive.
2) Groups C-D streptococci include commensal bacteria and opportunistic pathogens that can cause infections like pharyngitis, osteomyelitis, and bacteremia in debilitated individuals. Groups C-D are diagnosed using culture and rapid diagnostic tests.
3) Most streptococcal groups are treated with penicillin, while Enterococcus species (Group D) often require
4. Group B: Streptococcus agalactiae
• Regularly resides in human
vagina, pharynx, and large intestine
• Can be transferred to infant during
delivery and cause severe infection
– Pregnant women should be screened and
treated
• Wound and skin infections and
endocarditis in debilitated people
5. Deepa Babin 5
LAB DIAGNOSIS
Cultivation and diagnosis
ensure proper treatment
to prevent possible
complications
Rapid diagnostic tests
based on monoclonal
antibodies that react with
C-carbohydrates
Culture using bacitracin
disc test, CAMP
test, Hippurate hydrolysis
6. Deepa Babin 6
CAMP Test- S.agalactiae
• By Christie, Atkins, and Munch-Peterson
• In the CAMP test, group B streptococci release a soluble factor
(CAMP factor) that acts synergistically with the -hemolysin of
Staphylococcus aureus.
• A strain of -hemolysin producing Staphylococcus aureus is
inoculated down the center of a sheep blood agar plate.
• A single streak of an isolate to be identified is inoculated
perpendicular to the S. aureus streak to within 3-4 mm of the S.
aureus streak.
• The blood agar plate is then incubated overnight in an 35-37oC air
incubator
• If a large arrowhead zone of enhanced -hemolysis develops
between the unknown isolate and S. aureus the unknown isolate
is group B Streptococcus.
7.
8. • Groups C –Strep equisimilis species
– Common animal flora, frequently isolated from upper
respiratory;
pharyngitis,osteomylitis,glomerulonephritis, bactere
mia,brain abscess,puerperal sepsis
– Strep equisimilis- source of streptokinase
Group G,H,K O,R:
Group G- commensals of throat of man monkey
dogs
Occationaly-tonsilitis,endocarditis,UTI
Group H and K- Endocarditis
Group O- tonsilitis,endocarditis
Group R- Pigs(Septicemia,meningitis)
9. Treatment
• Groups A and B are treated with
Penicillin
• Long-term penicillin prophylaxis for
people with a history of rheumatic
fever or recurrent strep throat
10. Deepa Babin 10
Group D (Enterococci)
• Two groups-
Enterococcal gp and
Non Enterococcal
gp
– Enterococcus
faecalis, E.
faecium, E. durans
– Strep bovis,Strep
equinus- Non
Enterococcal gp
11. Deepa Babin 11
Group D (Enterococci)
• -Normal colonists of human large intestine,Genital
tract and saliva
– Cause opportunistic urinary, wound, and skin
infections, particularly in debilitated persons
– Intra abdominal abscess complicating
diverticulitis and peritonitis
12. Lab diagnosis
• Bile Esculin hydrolysis
– Ability to grow in 40% bile and hydrolyze Esculin
are features of Enterococci that possess Group D
antigen
• Growth in 6.5% NaCl broth
– Differentiates Group D streptococci from
enterococci
13. Treatment
• Treatment-Penicillin- Resistance(enterococci)
• P –R ,CHOICE IS VANCOMYCIN
• VRE- Vancomycin resitant Enterococci
• Enterococcal treatment usually requires
combined therap
• Cephalosporin's are inherently resistant
for Enterococci
14. Deepa Babin 14
Viridans Group
• Bacteremia, meningitis, abdominal infection, tooth
abscesses
• Most serious infection – Sub Acute Endocarditis – Blood-
borne bacteria settle and grow on heart lining or valves
• S. mutans produce slime layers that adhere to teeth, basis
for plaque
• Involved in dental caries
• Persons with pre existing heart conditions should receive
prophylactic antibiotics before surgery or dental
procedures
• Persons with pre existing heart disease are at high risk
• Colonization of heart by forming biofilms