Gastrointestinal Infections - Part 1 Flashcards
(30 cards)
What is the microbiology and pathogenesis of Campylobacter infection?
- Curved Gran-neg bacilli
- Inflammation, ulceration and bleeding
- Bacteraemia can occur
- Can lead to Guillain-Barre
What are the clinical features and treatments for Campylobacter infection?
- Incubation 2-5 days
- Bloody diarrhoea, abdominal cramps, fever
- Duration 2-10 days
- Treat with fluids, clarithromycin in persistent disease, quinolone or aminoglycoside for invasive disease
What is the microbiology and pathogenesis of Salmonella infection?
- Gram-neg bacilli
- Diarrhoea due to invasion of epithelial cells in distal small intestine, and subsequent inflammation
- Bacteraemia can occur
- Distant organs can be seeded
What are the clinical features and treatments for Salmonella infection?
- Incubation 12-72hrs
- Watery diarrhoea, vomiting, fever
- Duration 2-7 days
- Treat with fluids, beta-lactams, quinolones of aminoglycosides in severe infections
What is the microbiology and pathogenesis of Shigella infection?
- Gram-neg bacilli
- Organisms attach and colonise mucosal epithelium of terminal ileum and colon
- S. dysenteriae produces exotoxin (Shiga toxin) which can lead to HUS
What are the clinical features and treatments for Shigella infection?
- Dysentery
- Incubation 1-3 days
- Duration 2-7 days
- Watery followed by bloody diarrhoea, cramping abdominal pain
- Usually self-limiting, can give fluids
What is the microbiology and pathogenesis of Vibrio cholera infection?
- Comma-shaped Gram-neg bacilli
- Flagellae and mucinase facilitate penetration of intestinal mucous
- Attach to mucosa and diarrhoea production due to potent protein exotoxin
What are the clinical features and treatments for Vibrio cholera infection?
- Severe, profuse, non-bloody, watery diarrhoea
- Fluid loss and dehydration leads to hypokalaemia, metabolic acidosis and hypovolaemic shock
- Prompt oral or IV antibiotics indicated
What is the microbiology and pathogenesis of E. coli (specifically EHEC) infection?
- Gram-neg bacilli
- Attaching and effacing lesion
- Production of Shiga like toxin
- E. coli O157:H7 best known serotype
What are the clinical features and treatments for E. coli (specifically EHEC) infection?
- Incubation 1-7 days
- Duration 5-10 days
- Bloody diarrhoea, can lead to HUS (in case of O157:H7)
- Rehydration, antibiotics not indicated
What is the microbiology and pathogenesis of Yersinia enterocolica infection?
- Gram-neg bacilli
- Invades terminal ileum with inflammation of mesenteric lymph nodes
What are the clinical features and treatments for Yersinia enterocolica infection?
- Incubation 4-7 days
- Duration 1-2 weeks
- Diarrhoea, may have blood, abdominal cramps, fever and mesenteric adenitis
- Generally self limiting but may require quinolones or aminoglycosides in severe cases
What is the microbiology and pathogenesis of S. aureus infection?
- Gram-pos cocci
- 50% produce exotoxins, heat-stable and acid-resistant protein toxins
What are the clinical features and treatments for S. aureus infection?
- Incubation 30mins-6hrs
- Duration 12-24hrs
- Vomiting and abdominal cramps
- Self-limiting
What is the microbiology and pathogenesis of Bacillus cerus infection?
- Aerobic, spore-forming Gram-pos bacilli
- Two types of disease; emetic (toxin during storage) and diarrhoeal (toxin produced in gut)
What are the clinical features and treatments for Bacillus cerus infection?
- Incubation 30mins-6hrs
- Duration 12-24hrs
- Vomiting (not in diarrhoeal), watery diarrhoea and abdominal cramps
- Self-limiting
What is the microbiology and pathogenesis of Clostridium perfringens infection?
- Anaerobic, spore-forming Gram-pos bacilli
- Spores survive cooking and germinate
- Organisms ingested and sporulate in large intestine with production of enterotoxin
What are the clinical features and treatments for Clostridium perfringens infection?
- Incubation 6-24hrs
- Duration 12-24hrs
- Watery diarrhoea and abdominal cramps
- Self-limiting disease
What is the microbiology and pathogenesis of Clostridium botulinum infection?
- Anaerobic, spore-forming Gram-pos bacilli
- Foodborne, infant and wound botulism
What are the clinical features and treatments for Clostridium botulinum infection?
- Neuromuscular blockade results in flaccid paralysis and progressive muscular weakness
- Can lead to respiratory failure due to muscle weakness in chest/diaphragm
- Urgent intensive care support
- Antitoxin
What is the microbiology and pathogenesis of Clostridium difficile infection?
- Anaerobic, spore-forming Gram-pos bacilli
- Infection requires disruption of normal gut flora
- Often prior to treatement with antibiotics (i.e. clindamycin, fluoroquinolones, ciprofloxacin, penicillins and cephalosporins)
- Causes elimination of gut commensals and overgrowth of toxin producing C. difficile
- Diagnosed by finding toxin in the stool
- Treated with vancomycin
What are the clinical features and treatments for Clostridium difficile infection?
- Mild to severe abdominal pain, pseudomembranous colitis and colonic dilatation/perforation
- Stop precipitating antibiotics, give oral metronidazole in mild and vancomycin in severe cases
What is the microbiology and pathogenesis of Listeria monocytogenes infection?
- Gram-positive coccobacilli
- Invasive infection from GIT results in systemic spread via bloodstream
What are the clinical features and treatments for Listeria monocytogenes infection?
- Incubation around 3 weeks
- Duration 1-2 weeks
- Flu-like illness, can have diarrhoea, septicaemia and meningitis
- IV antibiotics (usually ampicillin and gentamicin)
