Transcript STREPTOCOCCI - Keluarga IKMA FKMUA 2010

STREPTOCOCCI
Streptococci
• facultative anaerobe
• Gram-positive
• chains or pairs
• catalase negative
(staphylococci are catalase positive)
Streptococcus in chains
Streptococcus pneumoniae (diplococcus). Fluorescent stain
• Streptococci
• Lancefield groups
*Satu atau lebih spesies per group
*antigen permukaan
groupable streptococci
• A, B and D
–most important
• C, G, F
–rare
Non-groupable
• S. pneumoniae
–pneumonia
• viridans streptococci
–e.g. S. mutans
* dental caries
hemolysis reaction - sheep blood
agar
• α (alpha)
– partial hemolysis
• green color
• β (beta)
– complete clearing
– A and B
• γ (gamma)
– no lysis
Hemolysis
• Groups A an B
–β
• Group D
–α or γ
• S. pneumoniae and viridans
–γ
• hemolysis reaction + one characteristic
–
presumptive identification
Group A streptococcus (S.
pyogenes)
•Group A streptococcal
menginfeksi semua umur
•Insiden tertinggi pd usia 5-15
thn
S. pyogenes -suppurative
• non-invasive
– pharyngitis
– Infeksi kulit, impetigo
• invasive bacteremia
– toxic shock-like syndrome
– "flesh eating" bacteria
– pyrogenic toxin
Pyrogenic toxin
• superantigen
• T cell mitogen
• Mengaktifkan sistem imun
Scarlet fever
• rash
• erythrogenic toxin
non-suppurative
• rheumatic fever
– inflammatory disease
– life threatening
– Sekuel kronik
• demam
• jantung
• sendi
• rheumatic tidak sama dengan
rheumatoid arthritis
Rheumatic fever -etiology
M protein
– cross-reacts heart myosin
– autoimun
Antigen dinding sel
– sedikit dicerna in vivo
– bertahan lama
Rheumatic fever
• penicillin
- menyembuhkan pharyngitis
- Menurunkan resiko carditis
Acute glomerulonephritis
• immune complex disease of kidney
Major pathogenesis factors
• lipoteichoic acid/F protein
– fimbriae
– binds to epithelial cells
• M protein
– anti-phagocytic
M protein
• major target
– Imunitas alami
• strain variation
– antigenicity
• re-infection
– Terjadi dengan strain yg berbeda
Capsules
• Anti-phagocytic
– mucoid strains
Isolation and identification
• β hemolytic colonies
– bacitracin menghambat
pertumbuhan
• β hemolytic colonies
– group A antigen
β hemolysis
• hemolysin O
– Sensitif oksigen
• hemolysin S
– Non sensitive oksigen
Post-infectious diagnosis
(serology)
• Antibodi thd streptolysin O
• Penting! Bila menetap sekuel
kronik terjadi
Serotyping
M
T
R
Group B streptococcus
• neonatal meningitis
• septicemia
• transmission
– vaginal flora
Group B streptococcus identification
• β hemolysis
• hippurate hydrolysis
• CAMP reaction
– meningkatkan β hemolisis S. aureus
Group D streptococcus
• Tumbuh pada bile esculin agar
– precipitasi hitam
6.5% salin
• Tumbuh
– enterococci
• Tidak tumbuh
– non-enterococci
Enterococci
• Hubungannya agak jauh dr streptococci
lain
• genus Enterococcus
• Flora usus
– urinary tract infection
• Kontaminasi dr anus
– opportunistic infections
• khususnya endocarditis
• Paling sering E. (S.) faecalis
Enterococci
• resisten thd banyak antibiotik
– termasuk vancomycin
• ujung D-ala diganti dengan D-lactat
Minute colony streptococci
Various groups (e.g. group A)
– berbeda scr genetik
* koloni yg besar (e.g. S. pyogenes)
– tdk ada demam rheuma
Koloni besar
Koloni kecil
Viridans streptococci
•
•
•
•
•
•
diverse species
oral
Karies gigi
α hemolytic dan negatif thd tes lain
non-groupable.
termasuk S. mutans
– endocarditis
– cabut gigi