Streptococcacae Flashcards
Types of Streptococcacae on Basis of Hemolysis
Alpha hemolysis
Beta hemolysis
Gamma hemolysis
Alpha hemolysis and color shown
Partial hemolysis
Green color
Alpha hemolysis include which organisms
V - S. Viridans
S. Pneumonia
Beta hemolysis and color shown
Complete hemolysis
Yellow color
Beta hemolysis is further classified on basis of
Lancefield Classification (C antigen)
Lancefield Classification
20 groups (A to V) - No I and J
Group A - S. Pyogenes
Group B - S. Agalactaie
Capsule of S. Pyogenes is made up of
Hyaluronic acid - cross react with synovial joints
Virulence factor of S pyogenes associated with cell wall
C antigen
Virulence factor of S pyogenes associated with outer membrane protein
M Protein - Similar to glycoproteins (Molecular mimicry)
Enzymes and toxins released by S pyogenes
Streptokinase - causes Fibrinolysis
Hyaluronidase - break Connective tissue
DNAase A, B, C ,D - DNAse B(M/I)
Hemolysin / Streptolysin
Streptococcal Pyrogenic exotoxin (SPE)
Serum opacity factor (SOF)
Types of Streptolysin/Hemolysin
Streptolysin -O
Streptolysin -S
Effect of O2 and heat on SL-O and SL-S
SL-O - Labile
SL-S - Stable
Which is antigenic - SL-O or SL-S
SL-O
Functions of SL-O and SL-S
SL-O - lethal, Cardiotoxic, Leucocidal
SL-S - Only Leucocidal
Hemolysis in SL-O and SL-S
SL-O - Deeper
SL-S : Surface
Types of Streptococcal Pyrogenic exotoxin (SPE)
A, B and C
A and C - Bacteriophage mediated
B - Chromosomal mediated
Streptococcal Pyrogenic exotoxin is associated with which diseases
Scarlet fever
Toxic Shock syndrome
Necrotizing Fascilitis
Suppurative Clinical features of Group A Streptococcal Infection
NIPPLES
N - Necrotizing Fascilitis
I - Impetigo
P - Pneumonia
P - Pharyngitis (Pain, Tender Cervical LN, No cough)
L - Lymphadenitis
E - Erysipelas
S - Streptococcal Toxic Shock syndrome, Scarlet fever
Erysipelas
Raised well demarcated, Painful red lesion (Superficial skin)
Clinical features of Scarlet fever
SCARLET fever
S - Sore throat
C - Circumoral Pallor
A - Antecubital fossa - Pastia line
R - Rash (Sandpaper)
L - Lymphadenopathy
E - Erythrogenic toxin (SPE)
T - Tongue (Strawberry)
Fever
Non suppurative Clinical features of Group A Streptococcal
PSGN
Rheumatic heart disease
PANDAS (Pediatric autoimmune Neuropsychiatric disorder associated with Streptococcus)
Transport media used for diagnosis of Group A Streptococcal
Pike’s media
Blood Agar finding for group A Streptococcal Infection
Pin point colonies
Wide zone Hemolysis
Selective media used for Diagnosis of group A Streptococcal
PNF
CVBA (Crystal Violet blood agar);
On Liquid media - Granular turbidity
Biochemical test used for diagnosis of Group A Streptococcal
PYR test positive
Bacitracin positive
Catalase and Oxidase Negative
Treatment of Group A Streptococcal Infection
Penicillin
Erythromycin in case of Resistance
Group B Hemolytic Streptococcal Infection is caused by
S. Agalactaie
Clinical features seen in Neonates (<1 week) associated with Group B streptococcus
i,iii,iv serotypes
Meningitis
Pneumonia
Sepsis
Clinical features seen in older children (1 week - 3 months)
Serotype iii
Pneumonia
Endocarditis
Lab diagnosis of Group B Hemolytic streptococcus
GALA CAMP HIP HIP HURRAY
GALA - Galactiae
CAMP - CAMP +ve
HIP HIP - Hippurate Hydrolysis +ve
huRRay - Resistant to Bacitracin
- Red/Orange pigment on Islam media
Arrangement of S. Viridans and S. Pneumoniae
S Viridans - Chains
S Pneumonia - Lanceolate
S. Pneumonia difference with S. Viridans
S. Pneumonia is Bile Soluble, Optochin sensitive and show Inulin fermentation
Whereas S. Viridans is Bile insoluble, Optochin resistant and Inulin fermentation is not seen
Streptococcus Viridans group includes
VIRAL MMS
S. Mitis
S. Mutans
S. Sangeris
S. Salivaris
S. Mutans is known for causing
Dental carries
S. Sangeris is known for causing
Late prosthetic valve endocarditis
Which organism have both Capsule and Slime layer
S. Salivaris
Virulence factors of S pneumoniae
Capsular polysaccharide
Shape of S. Pneumoniae
Lens/Lanceolate shape
capsule +ve
S Pneumoniae shows which colonies
Carrom coin colonies - elevated periphery and Depressed centres
Carrom coin colonies are also termed as
Draughts Mann colony
Treatment of S Pneumoniae infection
Beta lactams
If Resistance - 3rd gen Cephalosporins due to altered PBPs
Most common method of Resistance development in S pneumonia
Transformation
Clinical features shown by S pneumonia
Meningitis
Otitis media
Sinusitis
Community acquired pneumonia
Most common cause of Meningitis across all age
Streptococcus pneumonia
Gamma hemolysis includes
Group D non enterococcal
Enterococcus
Example of Group D non enterococcal
S. Gallolyticus
Example of Enterococcus
E. Faecalis
E. Faecium
Prevention of Pneumococcus
Pneumovax
Prevnar
Pneumovax vaccine
23 valent polysaccharide
Given to >5 years (immunity)
Not below 2 years
Prevnar
13 valent polysaccharide
Below 2 years
2,4,6 month - 12 to 15 month booster
Clinical features of Enterococcus infection
UTI (Catheter Associated infection)
Septicemia
Agar used for diagnosis of Enterococcus
Bile Esculin Agar - Black color
Enterococcus features
ENNNTER
E- Spectacle shaped Gram +ve cocci
N - Non motile
N - Non sporing
N - Nacl 6.5%
T - Heat tolerant
E - Bile Esculin agar
R - PYR +ve
Treatment of Enterococcus
Penicillin
If Resistance - Vancomycin
If Resistance to Vancomycin - Linezolid
