Bacterial URTI Flashcards
URTIs are caused mostly by ______
viruses
URTIs are Self-limiting in immunocompetent
T/F
T
Bacteria that cause URTI
List 4
• S. pyogenes
C diphtheriae
B. pertussis
H. influenzae
Streptococcal URTI
Causes _______ and _____
Pharyngitis and tonsillitis
Streptococcal URTI
Sequelae
__________ and __________ about _______ after throat infection
Acute rheumatic fever and rheumatic heart disease
1 – 4 weeks
Pharyngitis
• Inflammation of the mucous membranes of the _______ (Strept throat)
•______________
•______ while swallowing
oropharynx
Sore throat
Pain
Tonsillitis
• Fever - 38C • coughing.
• ____ache. • _____ache.
•______ swollen,
•________ lymph nodes
head; ear
Tonsils
Inflamed neck
S. pyogenes
______-haemolytic
Colonises the ____,_____,______,_______
Cause ______ and ________
Beta
mouth, throat, URT, vaginal tract
pharyngitis and tonsillitis
S. pyogenes
The most important virulence factors are the _______ and ______
Presence of ________
It produces other factors ( ______ and _______ substances)
M protein; capsule
Lipotechoic acid
toxins and extra cellular
S. pyogenes
produces other factors (toxins and extra cellular substances)
Eg
____________(_______)
________ ——-toxins
____________
Streptolysins (O and S)
Pyrogenic exo
Hyaluronidase
Lab detection of S.Pyogenes
Relevant specimen = ________
Gram stain morphology – Gram _____ (cocci or bacillus?)
throat swab
positive
Cocci
Lab detection of S.Pyogenes
Culture media –
______agar
——- agar
_________ agar
blood; chocolate; crystal violet blood
Lab detection of S.Pyogenes
Lancefield grouping
•classifies Streptococci based on the ____________ on the cell wall
group carbohydrate antigens
Lab detection of S.Pyogenes
Lancefield grouping
Group _____
A
Lab detection of S.Pyogenes
Bacitracin
Sensitive or Resistant
Sensitive
Bacitracin test
The bacitracin disk sensitivity test is used to differentiate the ________________
beta- hemolytic Streptococcus.
Bacitracin test
Select a _________________ and heavily inoculate a quadrant of a ________________ plate
An overnight culture is grown on _______ agar incubated _____°C in _____
beta-hemolytic colony
5% sheep blood agar
5% sheep blood
35
CO2
Infection of the upper respiratory tract usually involves the lungs.
T/F
F
Infection of the upper respiratory tract; usually does not involve the lungs.
Streptococcus Pharyngitis
Morphology:
grow on solid media as _____ colonies with ___-hemolysis on ______ agar
discoid
β; blood
Streptococcus Pharyngitis
Morphology:
facultative (aerobe or anaerobe?) and grow best at temperature of ___oc
anaerobe
37
Streptococcus Pharyngitis
Virulence factors:
____________–AntiPhagocytic
_______-_______ –Attachment
Antiphagocytic
_____ and enzymes
Hyaluronic Acid capsule
Pili –M Protein
Toxins
Streptococcus Pharyngitis
Virulence factors:
Hyaluronic Acid capsule –_________
Pili –M Protein – ________
Antiphagocytic
Toxins and enzymes
AntiPhagocytic
Attachment
Toxins and Enzymes of S.pyogenes
Hyaluronidase
•______ hyaluronic acid
• They are _______
Streptokinase
• Transforms _______ to _______
• Digests _____ and allows __________________
Splits
antigenic
plasminogen to plasmin
fibrin; bacteria escape from clots
Toxins and Enzymes
Deoxyribonucleases:
•_________ DNA (DNAses)
•It ______ _______ and facilitates spread of streptococci
• Haemolysins
•____________
•_______________
• they Both ________________
Degrade
Liquefies pus
Streptolysin O; Streptolysin S
lyse RBC membranes
Toxins and Enzymes of S.pyogenes
Pyrogenic Exotoxins
•___________Toxins
•Asspociated with ___________________ Syndrome & ___________
Erythrogenic
Streptococcal Toxic Shock
Scarlet Fever
Pyrogenic Exotoxins of S.pyogenes Act as super antigens.
T/F
T
