STREPTOCOCCI Flashcards
What family does Streptococci belong
Streptococcaceae.
Some species are part of the
indigenous human microbiota.
what type of microorganism does some species of Steptococcus belong
capnophilic
what makes their growth enhances where it is incorporated in culture media
blood, serum, or glucose
what mircoorganism are not included in the Lancefield classification
viridans group and S. pneumoniae
microscopy:
Gram positive spherical cells that are arranged in chains or pairs
culture:
Appear grayish, pinpoint, and translucent to slightly opaque while some species have mucoid
colonies.
biochemical tests:
(-) catalase, oxidase and gas production; non motile and ferments carbohydrates
Notorious pathogens:
Streptococcus pyogenes and Streptococcus pneumoniae.
classification of streptocococci
- Academic/ Bergey’s Classification
- SMITH AND BROWN CLASSIFICATION
- LANCEFIELD CLASSIFICATION
classification based on temperature requirement
- PYOGENIC GROUP
- VIRIDANS GROUP
- LACTIC GROUP
- ENTEROCOCCUS GROUP
classification based on Hemolytic pattern
- ALPHA HEMOLYTIC STREPTOCOCCI
- BETA HEMOLYTIC STREPTOCOCCI
- GAMMA / NON-HEMOLYTIC
classification based on the extraction of C CARBOHYDRATE from streptococcal cell wall
Lancefield classification
- Neither grow at 10°C nor at 45°C, but only at 37°C
- Mostly beta hemolytic reactions
- S.pyogenes and Groups C and G streptococci
pyogenic group
what temp does a pyogenic group grow
37°C
example of microorganism in pyogenic group
S.pyogenes and Groups C and G streptococci
- Grow at both 45°C and 37°C
- Not part of the Lancefield Group but some are
alpha hemolytic
viridans group
what temp does viridans group grows
45°C and 37°C
Not part of the Lancefield Group but some are alpha hemolytic
Viridans group
- It will grow at 10°C and 37°C
- Non-hemolytic and has Lancefield N antigen
- Often found in dairy products
- S. lactis, causes normal coagulation or souring of milk
Lactic group
what temp does lactic group grows
10°C and 37°C
Non-hemolytic and has Lancefield N antigen
lactic group
Often found in dairy products
LACTIC GROUP
- Grow at 10°C, 45°C and 37°C
- Part of normal microbiota of the human intestine
- E.faecalis
ENTEROCOCCUS GROUP
microorganism that causes normal coagulation or souring of milk
S. lactis
what temp does ENTEROCOCCUS GROUP belong
10°C, 45°C and 37°C
