STREPTOCOCCUS B,C,D,VIRIDANS

DEEPA BABINASST PROF

Travancore Medical College, Kollam

Hemolyic patterns on blood agar

Group B: Streptococcus agalactiae• Regularly resides in human vagina,

pharynx, and large intestine• Can be transferred to infant during

delivery and cause severe infection–Most prevalent cause of neonatal

pneumonia, sepsis, and meningitis–Pregnant women should be screened and

treated• Wound and skin infections and

endocarditis in debilitated people

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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

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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.

• Groups C –Strep equisimilis species– Common animal flora, frequently isolated from upper

respiratory; pharyngitis,osteomylitis,glomerulonephritis, bacteremia,brain abscess,puerperal sepsis

– Strep equisimilis- source of streptokinase

Group G,H,K O,R:Group G- commensals of throat of man monkey dogsOccationaly-tonsilitis,endocarditis,UTIGroup H and K- EndocarditisGroup O- tonsilitis,endocarditisGroup R- Pigs(Septicemia,meningitis)

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

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• Two groups- Enterococcal gp and Non Enterococcal gp– Enterococcus

faecalis, E. faecium, E. durans– Strep bovis,Strep

equinus- Non Enterococcal gp

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

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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

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

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

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