Streptococci Flashcards
Streptococci
- Gram Stain
- Aerobes or Anaerobes
- Structure
- Catalase
- Culture medium and subtypes, just the types will do
Gram + Aerobes - Cocci! not diplo - Catalase -ve! Blood Agar! - alpha hemolytic -- Greening Agar - beta hemolytic -- Clear Agar - non-hemolytic
Gimme all names of the hemolytic subtypes [6]
Alpha Hemolytic
- Greening; Strep Pneumoniae, Strep Viridan
- Differentiate by Optochin sensitivity; Strep Pneumoniae is sensitive, will die; Grows as Draughtsman Colony
Beta Hemolytics
- Lancefield groupings
- GAS: Strep Pyogenes
- GBS: Strep Agalacticae
- GDS: Enteriococci, S Bovis
Non Hemolytics
Group A Strep
- Location
- Virulence factors [4]
- Clinical test for virulence?
Strep Pyogenes
- Skin, Throat, Mucosa all possible
M protein
Erythrogenic toxin - Strep pyrogenic exotoxins SPE A, C
Streptolysin - ASOT - Anti-Streptolysin O Titer (antibodies)
Hyaluronidase
GAS Damages
Pharyngitis - Strep Throat
Can also have Scarlet Fever, rash by Erythrogenic toxin
- Sequelae: Rheumatic Fever, RHD; Sydenham’s chorea
– TYPE II HS! to own antigens; M Protein to Heart Myosin
Skin Infection, Toxic Shock Syndrome
- Impetigo, Erysipelas, Cellulitis, Necrotizing Fasciitis
- Epidermis, Dermis, Subcut, Fat-Fascia
- impetigo is sores and crust
- erysipelas more defined borders than cellulitis
- Sequelae: Post Strep Glomerulonephritis
- TYPE III HS! to strep antigens
Gimme histological presentation of Rheumatic Fever
Aschoff Bodies
- inflammatory nodule
- granulomatous
- Macrophages surrounding necrosis; Aschoff Giant Cells;
- Macrophages “Caterpillar” Anitschkow cells;
Note Strep Pyogenes Pneumonia mostly after viral infection first
Note CHOREA is a possible sequelae from ARF // HS II
Note post infectious sequelae are not caused by bacteria hence cannot culture;
okie;
Whats Impetigo
Whats Erysipelas
Whats Cellulitis
Whats NF
And their top bacteria causes
Impetigo - skin sores, crusts
– SA, SP
Erysipelas - dermis rash w distinct borders
– SP
Cellulitis - deeper than Ery
– SP more than SA
NF - Fascia plane dies cos underlying blood vessels infected
- SP (staph A also can; other bacteria also can)
What can cause TSS what to do?
TSS - SP, SA both can
- IVIG
- Clindamycin - Lincomycin class, decrease toxin production; 50s ribosome
GBS
- location
- damage
S Agalacticae
- GIT carriage; Vagina 30 30; asia fish outbreak
- Neonatal Sepsis, Meningitis; Meningitis for late onset, 1 week later
GDS
S. bovis
- EC, Bowel Cancer, HEPATOBILLIARY
Enterococci! - diplococci
- UTI UTI UTI
- EC, Hepatobiliary
Enterococci R and S
R: penicillin, cep
S: ampicillin, gentamicin
Whats the deal w Strep Pneumonia
- Location, Structure, agar;
- damagesss - and what pattern!
Location: upper respi tract common
Structure: Diplococci, Capsulated
- Gram + Diplococci ; alpha hemolytic, greening agar
Impt cause of CAP and Meningitis!
- Lobar Pneumonia!
- URTI, Sepsis also can;
Risk factors of Strep Pneumonia (cos of capsule)
Asplenia
Children, Elderly
Crowding
Alcohol
Pneumococci Vaccine?
Adults, Elderly give
- vaccine from capsule types - polysaccaride!!!
Kids
- give Conjugated vaccine; saccaride w protein
- Routine vaccine in Sg
Whats the deal w Strep Viridans
IEC
