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Flashcards in GI infections Deck (25):
1

Clostridium botulinum

Canned/vacuum food (honey for kids, beans for students).
Ingest preformed toxin. Inactivated by cooking.
Blocks ACh release, so paralysis, descending (cf GBS).
Tx: antitoxin.

2

Clostridium perfringens

Reheated meats, superAg enterotoxin.
8-16 hours incubation.
Acts on small bowel. Watery diarrhoea, cramps, 24 hours.

3

Clostridium difficile

Caused by Abx (cephalosporins/fluoroquinalones (-floxacin)).
Exotoxins A and B. Pseudomembranous colitis.
Metronidazole, or vancomycin if bad.

4

Bacillius cereus

Reheated rice (spores).
SuperAg, ^cAMP.
4 hours incubation.
Sudden vomiting. Watery diarrhoea.
Self-limiting.

5

Staph. aureus

G+. Catalase +, coagulase +. Tetrads. Beta-haemolytic.
Protein A stops IgG. Enterotoxin (superAg, IL1 IL2):
Prominent vomiting, water diarrhoea.
Self-limiting.

6

E coli

From human faeces.
G- enterobacter.
Facultative anaerobes, ferment lactose, oxidase -.
Self-limiting, but can give ciprofloxacin if dire.

7

ETEC

Toxigenic / Traveller's E coli.
Heat labile toxin LT stimulates adenyl cyclase ^cAMP;
ST stimulates guanylate cylase ^cGMP. (stable Ground)
Jejunum and ileum.

8

EIEC

Invasive dysentery E coli.

9

EHEC

Haemorrhagic E coli, so bloody diarrhoea. Verotoxin.

10

EPEC

Paediatric E coli: infantile diarrhoea.

11

HUS

Anaemia, thrombocytopaenia, renal failure,
due to E coli 0157:H7 toxin.

12

Salmonellae

?

13

Salmonella typhi

Typhoid fever.
Only transmitted by humans.
Multiplies in Peyer's patches.
Slow onset fever, *constipation*, spleen, rose spots, anaemia, leukopaenia.
Ceftriaxone or ciprofloxacin.

14

Salmonella enteridis

Poultry, eggs, meat.
Invades small and large bowel; rarely bacteraemia.
Diarrhoea.
Self-limiting.

15

Shigella (dysenteriae)

Shiga enterotoxin,
Bloody diarrhoea
due to musocal inflam in distal ileum and colon.
Self-limiting.

16

Yersinia enterocolitis

Domestic animal poo.
Enterocolitis, mesenteric adenitis, necrotising granulomata, reactive arthritis, erythema nodosum.
4oC "cold enrichment".

17

Vibrio cholerae

Human faeces, ? in shellfish.
cAMP opens Cl channel, lose Cl and water: massive diarrhoea without inflam.
Supportive Tx.

18

Vibrio parahaemolyticus

Raw seafood (Japan).
3 days diarrhoea.
Self-limiting, or Doxycycline.

19

Vibrio vulnificus

Shellfish - cellulitis in handlers.
In HIV: fatal septicaemia with D+V.
Doxycycline.

20

Campylobacter jejuni

Unpasteurised milk, poultry.
Curved, motile, oxidase +.
Prodrome: headache and fever.
Bloody foul smelling diarrhoea, abdo cramps.
Assoc: Guillain-Barré, reactive arthritis (Reiter's).
Erythromycin (or cipro if early). (Sensitive to nalidixic acid, first quinolone).

21

Listeria monocytogenes

Refrigerated unpasteurised food.
L-shaped, beta-haemolytic, aesculin +, tumbling.
Sepsis / meningitis / diarrhoea, cramps, headache, fever.
Perinatal infection, immunocompromised.
Outbreaks of febrile gastroenteritis.
Ampicillin, ceftriaxone, cotrimoxazole.

22

Entamoeba histiolytica

Ingestion of cysts (MSM).
Motile trophozoite (or in non-diarrhoeal, non-motile cyst). nuclei.
Flask-shaped ulcers. Colonise colon.
Dysentery (blood, tenesmus), weight loss, RUQ pain (liver abscess).
Metronidazole + paramomycin.

23

Giardia lamblia

Ingest cysts from water. Travellers/MSM/mentals.
Pear-shaped trophozoites.
Malabsorption of protein and fat, so foul smelling diarrhoea.
Dx: ELISA string test.
Metronidazole.

24

Cryptosporidium parvum

Severe diarrhoea from infected jejunum in immunocompromised.
Oocysts in stool - modified Kinyoun acid fast stain.
Paramomycin.

25

Viruses causing diarrhoea

Rotavirus: