Strept Flashcards
Characteristic
Progenies
upper respiratory tract (specially pharynx) and the skin
Non-motile and non-sporing
Fastidious
Some capsulated and others not.
Cannot live in the intestine or urine.
Strep. Agalactiae
➢ Characteristics
Gram +ve, chain forming cocci Commensal in in the GIT (colon) and some female genital tract (vagina) Capsulated
Non-motile
non-sporing
Fastidious
Strept.viridans
➢ Characteristic
Gram +ve chain forming cocci Normal flora of the oropharynx (especially the mouth
largest in number in mouth
Non capsulated
Strep. Pneumoniae
➢Characteristics
Gram +ve, diplococci, lancet shape with broad bases facing each other Commensal of the upper respiratory tract (oropharynx)
Capsulated Non motile and non sporing Fastidious
Faecalis
➢Characteristic
Gram +ve chain forming cocci normal commensal of the GIT (mainly colon), urethra and female genital tract
bovis characteristics
Pepto streptococci
normal flora on the GIT (mainly colon)
Normal flora of the: mouth, intestine and female genital tract.
Obligate anaerobes Produce variable hemolysis
Classification
Pyogene
s agalactiae
faecalis
bovis
pneumoniae Viridans
. Aerobes and facultative anaerobes
شوفي الجدول في الشيت ٤٢ ص
virulence factors Pyogenes
» Structural virulence factors:
1. M-protein
2. Lipo-Teichoic acid
4. Capsule
3. Pili
» Toxins:
1. Erythrogenic toxin
2. Streptolysin O
3. Streptolysin S
4. Pyrogenic Exotoxin A
5. Pyrogenic Exotoxin B
» Enzymes:
- Hyaluronidase
- Streptokinase “fibrinolysin”
- C5a peptidase
- DNase (streptodornase)
➢ Virulence factors Agalactiae
anti-phagocytic capsule
viridans ➢ Virulence factor
- Slim layer:
- Acid
Pneumoniae ➢Virulence factors
- Anti-phagocytic capsule 2. IgA protease 3. Lipoteichoic acid
Pyogenes Disease
✓Pyogenic infection
[1] pharyngitis and tonsillitis
[2] Cellulitis [3] Impetigo [4] Erysipelas [5] Endometritis (puerperal fever) [6] Bacteremia and septicemia
[7] Wound infection
[8] Streptococcal pneumonia
✓Toxigenic infections:
[1] Toxic shock syndrome [2] Necrotizing fasciitis [3] Scarlet fever
✓Immunogenic infections:
[1] Rheumatic fever [2] Acute glomerulonephritis (AGN)
Agalactiae ➢ Diseases
[1] Neonatal meningitis
[2] Neonatal sepsis
viridans ➢Diseases
Viridans cause pyogenic infection:
- Dental caries caused by the acid
- Sub-acute bacterial endocarditis
- Septicemia ✍️ Bactremia ?
- Brian abscess (mixed anaerobic infection)
Pneumoniae ➢
Diseases
(pyogenic infection) and mainly infect children:
Streptococcus pneumoniae is the most common cause for typical pneumonia, adult meningitis, and sinusitis, otitis media and mastoiditis Conjunctivitis
Streptococcus pneumoniae is the second most common cause for meningitis in children after Neisseria Meningitidis
Faecalis ➢
Diseases
- sub-acute Bacterial endocarditis 2. urinary tract infection (UTI)
- Biliary tree infection
- wound infection, 5. septicemia
bovis disease
endocarditis
Pyogenes 2c ✍️ 🙌
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Culturing Blood agar Crystal violet blood agar (selective media)
Biochemical test:
- catalase test is -ve
- bacitracin sensitivity test: sensitive to bacitracin
- ESR: In children with tonsillitis and pharyngitis and rheumatic fever
- ASO test: for patient with rheumatic fever
- Anti-DNase B test: for patient with AGN
Agalactiae 2c
➢Culturing: blood agar: show complete zone of hemolysis, but the zone is narrower than that caused by S. pyogenes
MacConkey agar: Can grow in 6-5% NaCl and 40% bile
Biochemical test:
Catalase test: -ve Na hippurate test: +ve Bacitracin sensitivity test: S. agalactiae is resistant CAMP test is +ve
viridans 2c
▪
Culture:
blood agar: alpha hemolytic; show partial zone of hemolysis in blood agar colonies appear green in color and nonmucoid
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Biochemical test Catalase test is –ve Swelling reaction: -ve Inulin fermentation test: -ve
Optochin and bile sensitivity test: resistance
Pneumoniae 2c
▪
Culture:
blood agar: alpha hemolytic; show partial zone of hemolysis in blood agar (in present of 5%-10% CO2 ) the colonies are green in color, smooth and mucoid due to capsule
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Biochemical tests:
- Catalase test: -ve
- Swelling reaction: +ve
- Optochin and bile sensitivity test: sensitive
- Inulin fermentation test: +ve
- latex agglutination test: for Rapid diagnosis of pneumococcal meningitis by detecting its capsular polysaccharide in spinal fluid
- detects urinary antigen (C polysaccharide also known as the C
Faecalis 2c ✍️
➢
Culture
- blood agar: show variable hemolysis
- MacConkey agar
- 6.5% NaCl (non- enterococci like S. bovis can Not) ➢
Biochemical test
▪
Bile - Esculin hydrolyzation test:
To differentiate between enterococci (e.g. S. facalis) and S. agalactiae
S. faecalis: hydrolyze Esculin + ve
S. agalactiae: does not esculin -ve
Pyogenes T 🙌
penicillin G (or erythromycin in allergic pts.): for treatment of tonsillitis, pharyngitis, scarlet fever
long acting penicillin (benzathine penicillin) once/month for year: for treatment of rheumatic fever
In necrotizing fasciitis:
1) I.V antibodies (penicillin G)
2) Surgical remove of damaged and dead tissue
3) Medication to raise blood pressure
In TSS we should:
1) removal of the cause (nasal packing or vaginal tampon)
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2) Correction of the shock by giving I.V fluids, adrenaline, antibodies against the TSST
3) Give antibiotics (vancomycin)
AgalactiaeT 🙌
For neonatal meningitis: Mainly Ampicillin (penicillin G can also be used)
For neonatal septicemia: combination of penicillin G + gentamycin (amino glycosides)
Strept.viridans T
Penicillin G or combination of penicillin G + gentamycin (amino glycosides) Erythromycin in allergic patient
Pneumoniae T
In pneumonia:
penicillin G (or erythromycin in allergic patients) vancomycin for penicillin resistant
In meningitis:
Ampicillin for neonates Ceftriaxone for children and adult
Faecalis T
Penicillin or vancomycin plus an aminoglycoside such as gentamicin is bactericidal.
Vancomycin-resistant enterococci (VRE) can be treated by linezolid, Synercid or daptomycin
Pepto streptococci T
penicillin G
