Microbiology - GI Infections Flashcards
What are the different types of clinical syndromes of GI infections?
- Secretory diarrhoea
- Inflammatory diarrhoea
- Enteric fever
What is the MoA of secretory diarrhoea, its features and some causative organisms?
MoA:
Toxin production causes Cl- to be secreted into the lumen, this causes a loss of water + electrolytes resulting in D+V
Features:
- Watery diarrhoea
- No fever
Causative organisms:
- Cholera
- ETEC
- EPEC
- Viruses
- Bacillus
- Staphylococcus. aureus
What is the MoA of inflammatory diarrhoea, its features and some causative organisms?
MoA:
- Inflammation + bacteraemia
Features:
- Bloody diarrhoea (dysentery)
- Fever
Causative organisms:
- Campylobacter jejuni
- Shigella
- Non-typhoidal Salmonella
- EIEC
What are the clinical features of enteric fever and some causative organisms?
Features:
- Unwell
- Fever
- Fewer GI Sx
Causative Organisms:
- Typhoidal salmonella
- Yersinia
- Brucella
What are some Sx + Buzzwords associated with Clostridium Botulinum?
- HONEY (kids)
- Beans (students)
- Canned/vacuum packed foods
- Ingestion of preformed toxin (inactivated by cooking)
- Blocks ACh release from peripheral nerves causing paralysis
DESCENDING PARALYSIS
What is the Abx of choice for Clostridium Botulinum?
IM Antitoxin
What are some Sx + Buzzwords associated with Clostridium Perfringens?
- Reheated meals (8-16hr incubation)
- Watery diarrhoea + cramps (for 24hrs)
GAS GANGRENE
What are some Sx + Buzzwords associated with Clostridium Difficile?
- 2 Exotoxins (A+B)
- Caused by Abx (4C’s - Clindamycin, ciprofloxacin, cephalosporins, co-amoxiclav) + fluoroquinolones + PPIs
- Severe diarrhoea + recent Hx of Abx
PSEUDOMEMBRANOUS COLITIS
What is the Mx for Clostridium difficile infection?
- Metronidazole
2nd line: - Vancomycin
What are some Sx + Buzzwords associated with Bacillus Cereus?
REHEATED RICE
- Short incubation (4hrs)
- Sudden vomiting + non-bloody watery diarrhoea
- Reheated rice (spores germinate) + sudden vomiting
What is the Mx for Bacillus Cereus infection?
Self-limiting - supportive
What are some Sx + Buzzwords associated with Staphylococcus aureus?
BBQs
- Gram +ve clusters of cocci on gram stain
- Produces enterotoxin (acts as superantigen causing IL1/2 release)
- Short incubation (2hrs)
- Prominent vomiting + watery diarrhoea
What is the Mx for staphylococcus aureus infection?
Self limiting - supportive
What are some buzzwords associated with ETEC (Enterotoxigenic E. coli) and its management?
- Gram negative
- Toxigenic
- Transmitted in faeces/contaminated water
- TRAVELLERS DIARRHOEA
Mx:
- Self limiting
- ?Cipro
What are some buzzwords associated with EIEC (Enteroinvasive E. coli) and its management?
- Gram negative
- Invasive
- Transmitted in faeces/contaminated water
- DYSENTERY
Mx:
- Self limiting
- ?Cipro
What are some buzzwords associated with EHEC (Enterohaemorrhagic E. coli) and its management?
- Gram negative
- Haemorrhagic
- Transmitted in faeces/contaminated water
Mx:
- Self limiting
- ?Cipro
What are some buzzwords associated with HUS (Haemolytic Uraemic Syndrome) and its management?
- Gram negative
- Enterohaemorrhagic
- Transmitted in faeces/contaminated water
- 0157:H7 TOXIN
- Anaemia, thrombocytopenia, renal failure (secondary to watery diarrhoea)
Mx:
- Self limiting
- ?Cipro
What are some buzzwords associated with EPEC (Enteropathogenic E. coli) and its management?
- Gram negative
- Pathogenic
- Transmitted in faeces/contaminated water
- INFANTILE DIARRHOEA (Paeds)
Mx:
- Self limiting
- ?Cipro
What are some Sx + Buzzwords associated with Salmonella Typhi/Paratyphi?
- Enteric fever
- Constipation
- Fever
- Splenomegaly
- Africa + India
ROSE SPOTS
What is the managment of Salmonella Typhi/paratyphi?
IV ceftriaxone then PO azithromycin
What are some Sx + buzzwords associated with Salmonella Enteritides?
POULTRY
- Eggs + meat
- Non-bloody diarrhoea (can sometimes be bloody)
What is the management of Salmonella Enteritides?
Self-limiting
Ceftriaxone if required
What are some Sx + buzzwords associated with Shigella?
- Distal ileum + colon
- Causes mucosal inflammation
- Fever
- Pain
- Bloody diarrhoea
What is the management of Shigella?
Self-limiting
Ciprofloxacin if required
What are some Sx + buzzwords associated with Vibrio Cholera and its management?
RICE WATER STOOL
- Massive diarrhoea without inflammation
- Comma shaped bacteria
- Africa + Middle East
Tx:
- Self limiting
What are some Sx + Buzzwords associated with Vibrio Parahaemolyticus and its management?
- Raw seafood
- Japan
Tx:
- Self limiting
What are some Sx + Buzzwords associated with Vibrio Vulnificus and its management?
- Cellulitis in Seafood handlers
Tx:
- Self limiting
What are some Sx + Buzzwords associated with Campylobacter Jejuni?
- UNDERCOOKED POULTRY
- Chicken at BBQ
- Prodrome of fever + headache, then abdo cramps + bloody diarrhoea
- Comma-shaped
- Lasts 10dys
- A/w GBS + reactive arthritis
What is the management of Campylobacter Jejuni?
Erthyromycin/Ciprofloxacin IF in first 5 days
What are some Sx + Buzzwords associated with Listeria Monocytogenes?
- Refrigerated food
- Unpasturised dairy
- PERINATAL INFECTION
- Severe infection in immunocompromised
What is the management of Listeria Monocytogenes?
Ampicillin
What are some Sx + Buzzwords of Entamoeba Histolytica?
FLASK-SHAPED ULCER (ulcers on caecum) on HISTOLOGY
- Liver abscesses
- DYSENTERY, flatulence, tenesmus
MSM
What is the management of Entamoeba Histolytica?
Metronidazole + Paromycin
What are some Sx + Buzzwords associated with Giardia Lamblia?
PEAR-SHAPED TROPHOZOITE
- Binuclei
- Causes malabsorption of fat leading to FOUL-SMELLING, non-bloody diarrhoea
- Ix = Stool ELISA + String Test
- Immunocompromised
What is the management of Giardia Lamblia?
Metronidazole
What are some Sx + Buzzwords associated with Cryptosporidium Parvum?
Severe (+prolonged) diarrhoea in IMMUNOCOMPROMISED
- HIV
- Ix = Stool OCP + Kingoun stain
What is the management of Cryptosporidium Parvum?
Paromomycin
What is the most common cause of GI infection?
Viruses
What are some Sx + buzzwords associated with Norovirus and its management?
- Secretory diarrhoea
HOSPITALS + CARE HOMES
- Adult outbreaks (winter)
- N+V
Tx:
- Self limiting
What are some Sx + Buzzwords associated with Adenovirus and its management?
Secretory diarrhoea
POOR HYGIENE
- <2yrs + IMMUNOCOMPROMISED
Tx:
- Self limiting
What are some Sx + Buzzwords associated with Rotavirus and its management?
Secretory Diarrhoea
- <6yrs
Unvaccinated Children
Tx:
- Self limiting
Which organsims cause dysentery (CHESS)?
- C: Campylobacter
- H: Haemorrhagic E.coli
- E: Entamobea Histolytica
- S: Salmonella
- S: Shigella
What is the general management of dysentery?
- Side room
- PPE + Wash hands
- Supportive: IV fluids, electrolytes, oral rehydration solution
