GI Infections Flashcards
Clostridia Botulinum
Anaerobic
Canned/vacuumed packed foods
Botulin toxin –> Descending paralysis
Blocks Ach release
Give antitoxin
Clostridia Perfringens
Anaerobic
Reheated meats
Superantigen enterotoxin
8-16 hrs incubation
Watery diarrhoea + cramps
Lasts 24 hours
Also causes gas gangrene
Clostridia Difficile
Anaerobic
2 exotoxins A, B
Pseudomembranous colitis
Tx: Metronidazole (and then vancomycin)
Bacillus cereus
Aerobic
Reheated rice
Superantigen
4 hrs incubation
Staph Aureus
Aerobic
Catalse coagulase positive
Beta haemolytic on blood agar
Superantigen
Prominent vomiting and watery non-bloody diarrhoea
Self-limiting
E. Coli
Gram negative enterobacteriaceae
Facultative anaerobes oxidase negative
Lactose fermenting
ETEC
EIEC
EHEC
HUS
EPEC
ETEC
Enterotoxigenic Escherichia coli
Toxigenic
Traveler’s diarrhoea
Heat labile LT stimulates adenyl cyclase and cAMP
Heat stable stimulates guanylate cyclase
EIEC
Enteroinvasive Escherichia coli
Invasive dysentery
EHEC
Enterohemorrhagic Escherichia coli
Haemorrhagic
Verotoxin
EPEC
Enteropathogenic E. coli
P = paediatric infection
infantile diarrhoea
Salmonella Typhi
(and paratyphi)
Non-lactose fermentors
Enteric fever
Multiply in Peyers patches
Slow onset fever and CONSTIPATION
Relative bradycardia
Splenomegaly
Rose spots
Anemia
Leukopenia
Tx: Ceftriaxone or ciprofloxacin
Salmonella enteritides
Non-lactose fermentor
Poultry, eggs and meat
Small and large bowel invasion
Non-bloody diarrhoea
Tx: ceftriaxone or ciprofloxacin if required
Shigella
Non-lactose fermentor
Distal ileum + colon
Mucosal inflammation
Fever
Pain
Bloody diarrhoea
Shiga enterotoxin
Ciprofloxacin if required
Yersina enterocolitis
Non-lactose fermentor
Enterocolitis
Mesenteric adenitis
Necrotising granuloma
Erythema nodosum
Cold enrichment 4’C
Vibriosis Cholera
Comma shaped
Late lactose fermentors
Oxidase positive
Rice water stool
Increased cAMP –> open Cl- channel
Vibriosis parahaemolyticus
Comma shaped
Late lactose fermentors
Oxidase positive
Ingestion of raw undercooked seafood (common in Japan)
3/7 diarrhoea
Self-limiting
Doxycycline
Vibriosis Vulnificus
Comma shaped
Late lactose fermentors
Oxidase positive
Cellulitis in shell-fish handlers
fatal sepsis and D&V in HIV patients
Doxycycline
Campylobacter Jejuni
Curved, comma, or S-shaped
Microaerophilic
Oxidase positive
Unpastuerised milk
Prodrome: headache, fever, abdo cramps
Bloody diarrhoea (foul smelling)
Assoc with Guillian-Barre, Reactive arthritis
Listeria monocytogenes
Beta haemolytic
Tumbling motility
Aesculin positive
Watery diarrhoea
Cramps, headache, fever, some vomiting
Ampicillin, Ceftriaxone, Co-trimoxazole
Entamoeba histolytica
Protozoa
MSM
Food, water and soil
Motile trophozoite in diarrhoea
Non-motile cyst in non-diarrhoeal illness
4 nuclei
Flask-shaped ulcer
Dysentery
Wind
Tenesmus
chronic weight loss and RUG pain due to liver abscess
Metronidazole + Paromomycin
Giardia Lamblia
Protozoa
Travellers, Hikders, MSM, psych units
Pear shaped trophozoites / cysts found in stool
cysts in water
Malabsorption of fat and protein
Foul smelling bloody diarrhoea
ELISA string test
Tx: Metronidazole
Cryptosporidium Parvum
Protozoa
Jejunum
Severe diarrhoea in immunocompromised
Modified Kinyoun acid fast stain —> see oocysts
Tx: Paromomycin
Viral diarrhoea
Rotavirus
Adenovirus
Norovirus
Poliovirus
Enteroviruses (coxsackie, ECHO)
