Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
17 Cards in this Set
- Front
- Back
- 3rd side (hint)
|
Gram stain, characteristics |
Gram positive, arranged in chains, non motile,non spore forming,non capsulated except Streptococcus pneumoniae which is capsulated |
|
|
|
Catalase test |
Negative |
|
|
|
Classification according to |
Hemolytic activity |
|
|
|
Examples of hemolytic activity |
ß hemolytic : Streptococcus pyogenes Alpha hemolytic: Streptococcus varidans and Streptococcus pneumoniae |
|
|
|
Streptococcus pyogenes classification |
Lancefield group A (based on carbohydrate composition on cell wall) |
|
|
|
Streptococcus pyogenes suppurative diseases( associated with presence of pus)-> specific diseases (caused only by it) |
1- sore throat and follicular tonsllitis 2-scarlet fever |
|
|
|
Streptococcus pyogenes suppurative diseases-> non specific diseases |
1- Impetigo 2- Puerperal fever 3- Erysipelas |
|
|
|
Streptococcus pyogenes non suppurative diseases (post Streptococcal sequel) |
Rheumatic fever Glomerulonephritis |
|
|
|
Direct method of diagnosis |
1- direct film: gram+ve cocci arranged in chains non non non 2-isolation-> n agar plate -> no growth, blood agar plate -> ß hemolysis |
|
|
|
Biochemical test |
Bacitracin sensitivity test: a bacitracin disc is put on a blood agar plate inoculated with the tested organism, a clear zone of inhibition is produced with Streptococcus pyogenes (GAS) that is sensitive while Streptococcus agalactiae (GBS) is resistant |
|
|
|
Indirect method ( serological diagnosis) |
Anti streptolysin 0 test (ASOT) A type of neutralization reaction User in diagnosis of Streptococcal complications by detecting the titer of antibodies firmed against streptolysin 0 toxin |
A state of trance |
|
|
Streptococcus viridans diseases |
Sub acute bacterial endocarditis (SABE) |
|
|
|
Streptococcus viridans examination |
1- direct film -> gram +ve cocci arranged in long chains non non non 2-isolation -> n-agar: no growth , blood agar: alpha hemolytic 3-identification-> macroscopical, microscopical,motility, biochemical test |
|
|
|
Biochemical tests |
1-Optochin sensitivity test: an Optochin disc is put on a chocolate or blood agar plate inoculated with the organism, if sensitive-> clear zone , Streptococcus viridans is resistant with no zone of inhibition 2-bile solubility test: few drops of bile salt are added to broth culture and left for 15 mins. If m.o. is soluble then the initial turbid culture will become clear. Streptococcus viridans is insoluble showing turbid tube |
|
|
|
Streptococcus pneumoniae diseases |
Lobar pneumonia (n.b it is a facultative anearobe |
|
|
|
Streptococcus pneumoniae diagnosis |
1-Direct film: a-gram +ve cocci arranged in pairs (diplococci) non motile, non spore forming BUT CAPSULATED b- Quellung reaction (capsule swelling test): One drop of anticapsular antibody is added to the film, and then one drop of Methylene blue is added-> capsule will be visible 2-isolation: n agar: no growth, blood agar: shows alpha hemolytic 3-identification: macroscopic, microscopic,motility:non motile, biochemical tests |
|
|
|
Streptococcus pneumoniae biochemical tests |
Optochin sensitivity test: sensitive; forming clear zone Bile solubility test: soluble so tubr becomes clear |
|
