Gram-negative bacteria Flashcards
What are virulence factors?
Any product or strategy that contributes to pathogenicity
Name some colonisation factors
adhesins, invasins, nutrient acquisitio
What shape are coliforms?
Rod-shaped
Are coliforms motile?
Most are due to peritrichous flagella
What do coliforms colonise?
The intestinal tract
True or false: negative bacteria are facultatively anaerobic
True
Enterobacteriaceae consists of multiple gram negative ___-shaped bacterial species
rod
Lactose fermentation produces ____
acid (used to distinguish between bacteria)
Which 2 bacteria show lactose use (ferment it to make acid) on appearance on MacConkey?
Escherichia coli and Klebsiella pneumoniae
MacConkey-lactose agar shows lactose fermenters in what colour?
Red (due to acid)
What colour do lactose fermenters turn phenol red in media?
Yellow
Do either salmonella or shigella ferment lactose?
No, neither
What are the flagellum made of?
Protein
What are the principal infections caused by pathogenic E. coli
Wound infections, UTIs, Gastroenteritis, Travellers’ diarrhoea, bacteraemia, meningitis (infants)
ETEC stimulates a chlorine transporter in the intestinal lumen to release i___ and w___ through toxins which leads to watery diarrhoea
ions and water
What does shigellosis cause?
Severe bloody diarrhoea
Where is shigella common?
In developing countries where sanitation is poor
True of false: Shigella is acid-tolerant
True
How does shigella spread?
Person-to-person, contaminated water and food
Shigella enters through colonic _ cells which overlie lymphoid follicles and deliver antigens to underlying immune cells
M
How does the shiga toxin in shigella cause cell death?
inhibits protein synthesis
What are the 2 species of salmonella?
S. enterica and S. bongori (rare - contact with reptiles)