MLSCI340 Enterics Flashcards
Common genera in family of Enterobacteriaceae that are associated with human pathogenicity
- Klebsiella
- Shigella
- Salmonella
- Escherichia
- Proteus
- Citrobacter
- Serratia
- Hafnia
- Yersinia
- Enterobacter
- Providencia
- Morganella
Normal flora in the gastrointestinal tract
- Enterobacteriaceae
- CNS
- Anaerobes
- Diphtheroids
- Enterococcus sp.
- Candida sp.
Obligate pathogens in the GI
- Aeromonas hydrophilia
- Salmonella enterica
- STEC; E.coli O157:H7
- Plesiomonas shigelloides
- Yersinia enterocolitica
- Shigella sp.
- Campylobacter jejuni
- Vibrio cholerae
Which pathogens are implicated in food poisoning/ food toxemias ?
- S. aureus
- B. cereus
- Clostridioides difficile
- C. perfringens
- C. botulinum
Which bacteria is associated with gastric, peptic and duodenal ulcers ?
Helicobacter pylori
Salmonella on MAC and HEK
MAC: wh
HEK: translucent blue-green +/- black center
Shigella on MAC and HEK
MAC: wh
HEK: translucent green
Yersinia on MAC and HEK
MAC: wh
HEK: pink/yellow
Yersinia on CIN
Cefsulodin Irgasan Novobiocin:
- translucent with red center
E. coli O157:H7 on SORB/SMac and CHROMagar Stec
colorless
Campylobacter on CBF
Campylobacter Blood Free:
- gy, moist, fltspr, or raised
Describe Principle of Tube Indole
- bacteria capable of hydrolyzing tryptophan (in peptone water) to form indole ?
- detected by colour rxn with dimethylamino benzaldehyde (Kovac’s)
- tube test could check for motility before adding Kovac’s by performing a wet mount
- differentiates lactose fermenters:
a). E. coli = POS
b). Klebsiella oxytoca (POS) vs K. pneumoniae (NEG)
red = POS
What is the general rule for order of inoculation of media plates and biochemicals ?
- liquid to solid
- least selective to most selective
What is the purpose for CNA ?
Colistin Naladixic Acid:
- selects for gram POS bacteria
- inhibits gram neg, normal flora
What is the purpose of PEA when incubated anaerobically ?
- isolates strict anaerobes
- facultative gram neg anaerobes (ie. Enterobacteriaceae) DO NOT GROW
- gram pos will grow (S. aureus)