Streptococci 3 Flashcards
Predisposing factors of lobar pneumoniae
- COPD
- Alcoholism
- Congestive heart failure
- Malnutrition
Clinical Manifestations: fever, chill, cough, pleuritic pain and
rusty-colored sputum
LOBAR PNEUMONIAE
may disseminate to the bloodstream to brain causing bacterial meningitis
LOBAR PNEUMONIAE
should have zones around optochin disks
S. pneumoniae
have no zone around the optochin disk.
viridans group streptococci
Expected result in Optochin test:
Zone of inhibition is 14 mm or greater in diameter with 6mm disk
Positive
Expected result in Optochin test:
No zone of inhibition
Negative
Expected result in Optochin test:
Any zone of inhibition less than 14 mm is questionable for pneumococci
Equivocal
Equivocal strain is identified as pneumococcus only if it is
Bile soluble
involves testing a pneumococcal cell suspension with pooled and specific antisera directed against the capsular polysaccharide.
Quellung (or Neufeld) reaction
Counterstain for Quellung (or Neufeld)
Methylene blue
Positive or negative:
observed when the capsule appears as a sharply demarcated halo around the dark blue stained cell
Positive
Positive or negative:
observed when there is no appearance of a clear, enlarged halo surrounding the stained cell.
Negative
Reagent used in bile solubility test
Sodium desoxycholate (bile salts)
Intraperitoneal inoculation of sputum with pneumococci to susceptible animal (mice)
Mouse Virulence Test
used to detect the presence of antibodies against streptococci
Francis skin test
uses particle-bound antibody to enhance the visibility of the agglutination reaction between antigen and antibody.
Coagglutination test
Streptococcus pneumoniae: TREATMENT
✓ Penicillin, Ceftriazone or Cefotaxime
✓ Trimethoprim sulfamethoxazole
✓ Quinolones such as levofloxacin, moxifloxacin, gemifloxacin
1st choice of blood agar plate for culture of genus streptococcus
Sheep’s blood
Culture used for laboratory diagnosis Of genus streptococcus
- Chocolate Agar Plate (CAP)
- Blood Agar Plate
Proffered medium of culture for laboratory diagnosis of genus streptococcus
Blood agar plate
2nd choice of blood agar plate for culture of genus streptococcus
Horse blood
In horse blood agar plate, more of what organisms snow hemolysis
Hemophilus organisms
3rd choice of blood agar plate for culture of genus streptococcus
Rabbit blood
