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;
14 Cards in this Set
- Front
- Back
|
Name the four species of Shigella |
Shigella dysenteriae - Group A Shigella flexneri - Group B Shigella boydii - Group C Shigella sonnei - Group D |
|
|
Describe the growth of Shigella species on BAP, MAC, XLD, HEK, and SS |
BAP - grey moist colonies, may be small MAC - NLF, colourless colonies. size varies with strain. Shigella sonnei is a late lactose fermenter XLD - red to colourless colonies. HEK - green/colourless colonies. SS - colourless colonies, most don't grow |
|
|
Describe useful biochemical identifications for Shigella species |
Motility - TSI K/A, no gas Lysine - (S. sonnei is positive for ONPG & ornithine) |
|
|
Describe Serological ID for Shigella |
test for O antigens slide agglutination some strains have a heat labile antigen overlying the O antigen, must be boiled and retested. |
|
|
Describe the clinical significance of Shigella species |
Shigella sonnei and Shigella flexneri most common isolates. Shigellosis is primarily a disease of children, transmitted via fecal oral route. Requires low bacterial numbers to cause infection. Symptoms of Bacillary Dysentery - 1-3 days post ingestion. watery diarrhea, cramps, blood, mucus, pmns in stool. rarely needs antimicrobial intervention. Shigella dysenteriae produces shigatoxin (as well as EHEC) |
|
|
Describe the growth of Salmonella on BAP, MAC, XLD, and HEK plates |
BAP - gray moist colonies MAC - LNF XLD - red colonies w black centre HEK - blue green with black centre |
|
|
Give useful biochemical tests for Salmonella |
Lactose negative H2S positive deaminase negative lysine positive |
|
|
Give test results to differentiate Salmonella typhi from other Salmonellas |
H2S - only a small amount Ornithine - negative Citrate negative anerogenic |
|
|
All O antigens for Salmonella serotyping come up as negative. what must be done? |
boil off the heat labile Vi antigen, retest. |
|
|
what are the two main types of Salmonella infections? |
Enteric fever Gastroenteritis |
|
|
Describe Typhoid fever |
caused by Salmonella typhi incubates for 8-14 days blood, stool, urine suitable for culture Blood best for culture in first week stool usually not positive in first week Dx can be made if antibodies against O and H antigens present in patient's serum. high Vi antibody may indicate a carrier state |
|
|
describe the growth of Citrobacter freundii on BAP, MAC, SLD, HEK, and SS agars |
BAP - grey moist colonies MAC - LF or NLF XLD - yellow, colourless, or red colonies that may have a black centre HEK - Salmon or blue-green colonies that may have a black centre SS - pink or colourless colonies that may have a black centre |
|
|
Describe test results that differentiate Citrobacter freundii from lactose fermenters |
H2S positive Lysine negative |
|
|
Describe test results that differentiate Citrobacter from Salmonella |
ONPG positive Lysine negative |
