Microbiology 6 - GI infections Flashcards
In a febrile patient with a GI infection, what are the key differentials?
- Inflammatory diarroea
2. If no diarrhoea - enteric fever (typhoid/ salmonella)
In an afebrile patient with a GI infection, what is the top differential?
Secretory diarrhoea due to toxins (eg cholera)
What is the incubation period of campylobacter?
1-10 days
What is the incubation period of bacilus cereus?
1-6 hours
Why does staph aureus food poisoning produce such rapid symptoms?
Toxin is pre-formed
What are the key cytokines involved in Staph aureus food poisoning?
IL-7 and IL-2
Describe the symptoms of S aureus food poisoning
Vomiting
Waterey, non-bloody diarrhoea
Describe the different toxins produced by bacilus cereus
Heat-stable toxin causes emesis
Heat-labile toxin causes diarrhoea
Only the heat-labile toxin is destroyed upon heating
Describe the diarrhoea produced by bacilus cereus
Waterey, non-bloody
In what type of food might clostridia botulinum be found?
Honey
What type of clostridia spp causes food poisoning?
Clostridia perfringens
In what sort of food is clostridia perfringens found?
Re-heated meat
Which organism causes pseudomembranous colitis?
Clostridium difficile
Which diarrhoeal disease is associated with antibiotic use?
Pseudomembranous colitis caused by C. difficile
What type of symptoms does listeria monocytogenes poisoning cause?
Febrile gastroenteritis
Waterey diarrhoea
Recall 2 sources of listeria poisoning
Unpasteurised dairy Refringerated foods (eg sandwiches)
Is listeria alpha or beta haemolytic?
Beta haemolytic
What is the causative organism in ‘traveller’s diarrhoea’?
Enterobacteriacae (usually the toxogenic form, ETEC)
What organism causes haemolytic uraemic syndrome?
EHEC enterobacteriacae
Recall one very important thing to avoid in the management of enterobacteriacae poisoning
Antibiotics
Recall 3 worrying species of salmonella
S typhi
S enteritidis
S cholerasuis
What symptoms are caused by S typhi infection?
Bactaraemia
Constipation and fever
Splenomegaly and ROSE SPOTS
What are the 2 key forms of shigella that cause disease in humans?
S dysenteriae S flexneri (associated with MSM)
What disease pattern does shigella infection cause?
Dysentry
How should shigella infection be managed?
Avoid antibiotics
If really necessary, go for ciprofloxacin
What is the typical stool appearance in Vibrio cholerae infection?
Rice water
Which organism is most likely to cause cellulitis in a scuba diver?
Vibrio vulnificus
On what sort of agar can vibrio spp be grown?
Salty agar
For how long can campylobacter symptoms last?
Up to 20 days
What is one key serious complication of campylobacter infection?
Guillan Barre syndrome
What is the symptom of “flask-shaped ulcer” pathognemonic for?
Entamoeba histolytica infection
What symptoms does E. histolytica infection cause?
Dysentry and flatulence
How should E. histolytica infection be managed?
Metronidazole
How can giardia infection be investigated?
String test
How should giardia infection be treated?
Metronidazole
In which patient group does cryptosporum parvum cause symptoms, and what are those symptoms?
The immunocompromised
Severe diarrhoea
Recall the 1st and 2nd line treatments for clostridium difficile
- Metronidazole
2. Vancomycin
