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Pyogenic cocci
Marut LaohavirojMD, PhD
Department of Microbiology,
Faculty of Medicine, KKU
Outline
-Bacterial identification -Clinical signs and symptoms-General characteristic -Treatment-Pathogenesis
Streptococci Pathogenic NeisseriaStaphylococci
4
Pyogenic cocci
• Gram positive cocci
Staphylococcus spp.
S. aureus, S. epidermidis, S. saprophyticus
Streptococcus spp.
S. pyogenes, S. agalactiae, S. pneumoniae, Viridans streptococci Enterococcus spp.
• Gram negative cocci
Neisseria spp.
N. gonorrhoeae, N. meningitidis
Catalase test
Gram-positive cocci
Stre
pto
cocc
us
spp
.En
tero
cocc
us
spp
.St
ap
hylo
cocc
us
spp
.
(+)
(-)
Staphylococci
Coagulase test Fibrinogen Fibrin(plasma) (clot)
Co
ag
ula
se n
ega
tive
St
ap
hylo
cocc
iSt
ap
hylo
cocc
us
au
reu
s
(+)
(-)
Staphylococci test
Coagulase
leukocyte destruction and tissue necrosis
Virulence factors S.aureus
Virulence factors S.aureus
1. Cell Surface Factors
Teichoic acid promoting adherence, antigenic determinant.
Protein A binds Fc portion of IgG
Fibronectin-binding Proteins
2. Secreted Factors:
Superantigens: Enterotoxins, TSST-1,
alpha-toxin (dermonecrotic)
3. Cytolysins : hemolysin, leukocidin family (PVL)
(Panton-Valentine leucocidin)
4. Enzyme: Lipase, DNAse, Penicillinase, hyaluronidase,
Proteases (Exfoliative toxin, epidermolytic toxin, (ETA &ETB))
Folliculitis Furuncle/Boilspainful nodule
Carbuncle (ฝฝกบว)
Staphylococcal scalded skin syndrome (SSSS): Exfoliative toxin causes blisters
CLINICAL MANIFESTATIONS
Skin and soft tissue infection
• Impetigo (infection of the epidermis)
• Folliculitis (infection of the superficial dermis)
• Furuncles, carbuncles, and abscess (infection of the deep dermis)
• Hidradenitis suppurativa (follicular infection of intertriginous areas)
• Cellulitis, erysipelas, and fasciitis (infection of the subcutaneous tissues)
• Pyomyositis (infection of skeletal muscle)
• Mastitis
• Surgical site infections
CLINICAL MANIFESTATIONS
Bacteremia
Infective endocarditis — S. aureus is the most common cause of infective endocarditis (IE)
• Risk factors for IE in the setting of S. aureus bacteremia:
• Prosthetic heart valve (incidence up to 50 percent)
• Predisposing cardiac abnormalities
• Injection drug use (IVDU)
• Intravascular catheter infection
Bacteremic spread and endocarditis are most common in drug abusers
Staphylococcus aureus
เกาะตด
Staphylococcus epidermidis
• Coagulase negative, normal skin flora
• The ability to form biofilms on devices is a major virulence factor
• Risk: Catheters• Prosthetics• Shunts• IV needles
• Prosthetic valve endocarditis; Prosthetic joint.
• Strains of S. epidermidis that produce a glycocalyx are more likely to adhere to prosthetic implant materials
Important Features of Pathogenesis by Staphylococci
Organism Type of Pathogenesis Typical Disease Predisposing Factor Mode of Prevention
S. aureus 1. Toxigenic (superantigen)
Toxic shock syndrome Vaginal or nasal tampons Reduce time of tampon use
Food poisoning Improper food storage Refrigerate food
2. Pyogenic (abscess)
a. Local Skin infection (e.g., impetigo, surgical-wound infections)
Poor skin hygiene; failure to follow aseptic procedures
Cleanliness; handwashing; reduce nasal carriage
b. Disseminated Sepsis, endocarditis IV drug use Reduce IV drug use
S. epidermidis Pyogenic Infections of intravenous catheter sites and prosthetic devices
Failure to follow aseptic procedures or remove IV catheters promptly
Handwashing; remove IV catheters promptly
S. saprophyticus Pyogenic Urinary tract infection Sexual activity
(Review of Medical Microbiology & Immunology: A Guide to Clinical Infectious Diseases, 15e)
Streptococci
Streptococci spp.Gram positive cocci, Chain /diploccocci - Normal flora in throat, intestine
•Brown’s classification (Hemolytic activity)
• Lancefield grouping(Serology)
Complete hemolysis Partial hemolysis Non-hemolysisS. pyogenes
/Beta-streptococcus gr. A (GABS) (GAS)S. agalactiae
/Beta-streptococcus gr. B (GBS)
S. pneumoniae
Viridans streptococci
Enterococcus faecalis
Enterococcus faecium
S.bovis
20 serologic classification A-V
Ex.
Beta-hemolysis• Group A streptococci (S. pyogenes) ( GAS),
( Streptococcal pharyngitis; Strep sore throat.)
Bacitracin sensitivity test-ใชแยก gr.A
กอโรคไดทกระบบ โดยเฉพาะ URI
• Group B streptococci (S. agalactiae)(GBS):
อยในชองคลอด กอโรคในเดกแรกเกด
Streptococcus pyogenes (GABS)Gram-positive cocci in chain
(SPE, erythrogenic toxin) >> Scarlet fever, toxic shock syndrome
Streptodornase (DNAase): degrade DNA
Virulence factors
1.Cell surface• Protein M: Adhesion, สลาย C3b, antiphagocytosis,
• Capsule antiphagocytosis,• Pili
2. Enzymes• Hyaluronidase
• Fibrinolysin ( Streptokinase)
• DNAse : anti-DNAse B• Amylase
Virulence factors
3. Toxins
• Streptococcal pyrogenic exotoxins (SPE)/ Erythrogenic toxin:
Scarlet fever
• Septicemia -Toxic shock like syndrome
• Streptolysin (hemolysin)
• Streptolysin O : Anti-streptolysin O (ASO- titer)
Streptolysin S
doughnut sign in acute streptococcal pharyngitis
Streptococcal sore thorat Epstein–Barr virus (EBV)
Peritonsillar Abscess
Scarlet fever
Sand paper like rash Circumoral pallor
Desquamation
Pastia's line
Strawberry tongue
Erythrogenic toxin
Erysipelas (ไฟลามทง)ตดเชอใน epidermis และ lymphatic tract/ GABS
Complication from Streptococcal infection
1. Acute rheumatic fever
2. Acute Post Streptococcal Glomerulonephritis( APSGN)
Hypertension
3. Necrotizing fasciitis
Streptococcus pyogenes
Group B Streptococci : GBS:(S. agalactiae)
• Polysaccharide capsule• Sialic acid in capsule inhibit
alternative compliment and neutrophil activity)
GBS: ascending infection in pregnant women
Early onset infection in neonate (7 days)
Gram positive diplococci lancet shape
Streptococcus pneumoniae
Optochin disc
Virulence factor: Capsule
Tx: Penicillin
Quellung reaction; Antisera directed against the capsular polysaccharide.
CbpA: Choline-binding proteins; adhesin/ invasion/ evasionPneumococcal surface proteins A and C (PspA and PspC),: adhesin
invasion/ evasion
Cytotoxic
Opsonization
• S. mutans, S.mitis, S.sanguis
• Resident oral microbiota of humans
• Subacute bacterial endocarditis (SBE)
• Tx: Penicillin
Viridans group streptococci
g- hemolysis : non-hemolysis
Gr. D streptococci/ enterococci• Enterococcus faecalis
• Enterococcus faecium
• อยในล ำไส
• Nosocomial infection, UTI, endocarditis, sepsis
• Drug resistant: Pen, Ceph, Aminoglycoside
• Drug of choice : Ampicilin / vancomycin/ BL-BI
Enterococcus spp.
Gram positive cocci short chain Non hemolysis
Capsule: OpsonizationDRSP: Drug resistant S. pneumoniae
ATB spectrum
Neisseria spp.
Neisseria spp.
Gram negative diplococci kidney shape
1. Pathogenic Neisseria
-N.gonorrhoeae
-N.meningitidis
2.Non- Pathogenic Neisseria
- Normal flora
Oxidase test
Detects the presence of a cytochrome oxidase system that will catalysethe transport of electrons between electron donors in the bacteria and a redox dye- tetramethyl-p-phenylene-diamine.
Neisseria gonorrhoreae
• Grow on chocolate agar, and incubated in a moist environment at 37ºC under an atmosphere of 3 –10% CO2
Virulence factors
• Pili >adherence: N.g, N.m
• Capsule> antiphagocytosis : N.m
• Endotoxin : N.m
• IgA1 protease N.g
• Outer membrane protein (OMP)>
• Adhesion &invasion
• Iron - binding protein
Neisseria meningitidis
• Meningococcemia
• Hemorrhagic rash ( purpura fulminans ) with DIC ( disseminated intravascular coagulation)
• Waterhouse-Friderichsen syndrome (Adrenal gland failure due to hemorrhage)
• Meningitis
• Nasopharynx ของพาหะ ปกต 2-8%
• พบในบรเวณทคนแออด
• ผปวย 50% ต ากวา 5 ขวบ
• Virulent factors• Capsule, pili, endotoxin, OMP
community-acquired bacterial meningitis in both children and adults
Purpura fulminans
Neisseria spp.
Moraxella catarrhalis ?
Contacted case?