Bacterial Gastroenteritis Flashcards
How is bacterial gastroenteritis diagnosed? (4)
- bacteria culture on selective media
- confirm ID of colonies
- antimicrobial susceptibility testing
- multiplex PCR
What species of campylobacter cause gastroenteritis?
- c. jejuni
- c. coli
- c. foetus
When do campylobacter cases peak?
summer
How do people contract campylobacter? (2)
- raw or undercooked foods
2. cross contamination from raw to cooked/ready to eat foods
What is the pathogenesis of campylobacter in the GIT?
attach to and invade the GI epithelium of the jejunum, ileum, colon, rectum
What is the incubation period of campylobacter infection?
1-7 days
What are the clinical features of campylobacter infection? (5)
- abdominal pain
- diarrhoea (may be bloody)
- nausea
- vomiting
- fever
what are the complications of campylobacter infection? (2)
- guillain-barre syndrome
2. reactive arthritis
How is campylobacter managed? (3)
- rehydration
- electrolyte replacement
- antimicrobials usually not indicated
When should antibiotics be considered? (5)
- worsening symptoms
- symptoms lasting >1 week
- severe disease
- immunocompromised
- pregnant
What antibiotics can be used to treat campylobacter infections if neccessary? (2)
- macrolides
2. fluoroquinolones
What is the morphology of campylobacter?
gram negative curved bacilli
What selective media is used to culture campylobacter?
charcoal based selective media - flat colonies
How is campylobacter diagnosed in a lab?
- culture on charcoal based selective media
- susceptibility testing
- PCR
What salmonellae cause enteric fever? (2)
- salmonella enterica serotype typhi
2. salmonella enterica serotype paratyphi
What are non-typhoidal salmonellae? (2)
- salmonella enteritidis
2. salmonella typhimurium
Where is enteric fever found?
developing countries
What are the routes of transmission of enteric fever? (3)
- contaminated food and water
- poor sanitation and hygiene
- person to person occasionally
What is the pathogenesis of salmonella enterica?
- penetration of small intestinal epithelium
2. proliferation in submucosa - hypertrophy of peyers patches
What is the incubation period for enteric fever?
usually 2 weeks
What are the clinical features of enteric fever? (10)
- fever
- chills
- relative bradycardia
- abdominal pain
- rose spots
- hepatosplenomegaly
- GI bleeding
- perforation
- diarrhoea
- constipation
What are the complications of enteric fever?
- GI perforation
- seeding
- carriage
How is enteric fever diagnosed? (3)
- blood culture
- faeces culture
- bone marrow culture
How is enteric fever treated? (3)
- rehydration
- fluoroquinolones
- 3rd generation cephalosporins
How can enteric fever be prevented? (3)
- sanitation
- hygiene
- vaccination
How is non-typhoidal salmonellosis transmitted?
- contaminated food and water
- exotic pets
- person to person
What is the incubation period for non-typhoidal salmellosis?
6-48 hours
How long does diarrhoea last in NTS?
3-7 days
How is NTS treated?
- rehydration
2. antimicrobial usually not required
When is antimicrobial use indicated in treating NTS?
- severe illness
- less than 1 or over 50
- HIV
- immunocompromised
How is Salmonella diagnosed? (3)
- selective media - salmonella shigella agar
- serotyping - antigen determination
- PCR
What is antigens does salmonella have? (3)
- O cell wall
- H flagella
- Vi Surface
What is EHEC and VTEC?
enterohaemorrhagic e coli
verocytotoxin producing e coli
What is ETEC?
enterotoxigenic e coli
What is EIEC?
enteroinvasive e coli
What is EPEC?
enteropathogenic e coli
What is EAEC?
enteroaggregative e coli