Enterobacterales Flashcards
Are enterobacterales oxidase positive or negative?
Oxidase negative
How are enterobacteria identifiable?
Gram negative, oxidase negative bacilli/rods that grow on MacConkey agar as LF/non-LF colonies
What are the antigens expressed by different enterobacteria serotypes?
Somatic ‘O’ antigens
Flagella ‘H’ antigens
What are the common diseases caused by E. coli?
- UTI
- Neonatal meningitis & septicaemia
- Gut-related sepsis - billary infections
- Diarrhoea
What serotype of E. coli causes traveller’s diarrhoea?
Enterotoxigenic E. coli (ETEC) causes 20-40% of traveller’s diarrhoea
What are the most common sources of E. coli bacteremia?
Urine and billary sources
What is the strain of E. coli responsible for bloody diarrhoea?
Enteroharmorrhagic E. coli (EHEC)/ Verotoxin-producing E. coli (VTEC)/ Shiga Toxin E. coli (STEC)
What is the gene that codes for the shiga toxin?
0157:H7
What serious complication is caused by the shiga toxin?
Haemolytic Uraemia Syndrome (HUS) which may lead to renal failure
Where does S. Typhi come from?
Humans
Where does non-typhoidal Salmonella spp come from?
Mainly poultry/eggs but also other animals
What are the common presentations of a non-typhoidal Salmonella infection?
- Gastroenteritis
- Bacteremia in immune-compromised patients
- UTI
What are the common presentations of a typhoidal Salmonella infection?
- Enteric fever
- Rose-spot rash
- May have diarrhoea or constipation
How is typhoid fever diagnosed?
Blood cultures
How can typhoid fever be prevented?
Hygiene and proper sewage disposal
Vaccination - live-attenuated & conjugated