Gastroenteritis.txt

• Giardia lambia
• Strongyloides stercoralis
• Intestinal TB
• AIDS

• Tropical sprue: india, SE asia
• Non bloody diarrhoea +/- steatorrhoea
• Abdo bloating
• Significant weight loss

Partial villous atrophy

• Tetracycline: for associated bacterial small bowel overgrowth
• Folic acid

• Notifiable disease
• Tell CCDC

• 1. Typhoid or enteric fever causing salmonella: not food poisoning or GE. They cause infections of RES – systemic. Salmonella typhia, paratyphia A, B, C
• 2. Non-typhoid: do cause food poisoning and GE. Eg salmonella enteritidis, typhi murium

Classified based on Antigenic nature of O or somatic ag that envelopes the organism.

G-ve rod

• Multiplication of organisms in intestines
• Epithelial cell damage

16-48 hours so ask about many previous meals

• Slight vomit
• Moderate, maybe bloody diarhhoea
• Abdominal pain
• Fever as it is INVASIVE

Egg: because oviduct inside egg is contaminated with salmonella (raw eggs)

Lion brand in UK shows chickens that laid those eggs were vaccinated against salmonella

Yes

Cheap Spanish non red lion marked eggs

In chinese restaurant eggs swished around everywhere so if veg are in contact with surface where egg was then can get it

Campylobacter

Salmonella

• Gram –ve rod
• Sea-gull shape
• c. jejuni

Colonises gut, multiples there, release ENTEROTOXIN in gut

16-48 hours so ask about many previous meals

Campylobacter much worse

• Nausea
• Profuse bloody diarrhoea
• Crampy abdo pain due to toxin
• Fever as invasive

• Chicken – it is normal flora of chicken bowel
• Summer BBQs: brown on outside, pink inside

• Bacillus cereus
• Staph aureus
• They produce enterotoxins

G+ve rods (purple)

• 1. Emetic enterotoxin: is swallow enters blood stream, hits vomiting centre in brain and so vomit
• 2. Diarrhoaegenic enterotoxin: receptors on mucosa of small and large bowel

• Half hour to 6 hours get profuse vomiting first
• Eating pre-formed toxin (as food already contaminated with toxin)
• Inoculum effect – if eat heavily and swallowed lots of organisms get diarrhoea faster

• Profuse vomiting
• Diarrhoea if toxin present
• No abdo pain or fever

Rice: organism uses c/h in rice as energy source to produce potent toxins

• Chinese restaurant or take-away meal
• Cook large volumes of rice and not left in cold room or covered

• Flash fry the rice and so don't denature the organism as need 100 degrees to denature
• Toxins are heat stable

• They are spores
• Found in animal and human dung and dust
• They can land in rice and start to germinate, multiply and release toxin into culture medium

Heat stable staph enterotoxin

• Half hour to 6 hours get profuse vomiting first
• Eating pre-formed toxin (as food already contaminated with toxin)
• Inoculum effect – if eat heavily and swallowed lots of organisms get diarrhoea faster

• Profuse vomiting
• Slight diarrhoea

• Milk or milk products
• Previously due to cow mastitis, or milker having staph aureus paronychia
• Now lots of legislation
• On holiday – may want to milk the cows
• Food handler: cook or chef sweating or skin flakes into pan. Some toxins denatured at high temperatures but when serve up dish and food cools down the temperature range is such that toxin can still have effect

• G+ve rod
• Normal flora of human and animal bowel

As it is normal flora so even if found in stool sample may not be abnormal. Need to locate the food source and see if it had lots of c.perf

Multiplication of organisms and release of enterotoxin in the gut during sporulation

12-24 hours

• Diarrhoea
• Colicky abdo pain
• No fever as toxin associated

• c. perferingens
• e coli

Gut normal flora

E coli O157 (all enteric organisms have a somatic O antigen) aka enterohaemorrhagic e coli, vero toxin ecoli,

• Swallow e coli (don't need much of it)
• Colonise bowel, Multiplication of organisms and release of potent cyto entero toxins so acts on cells and receptors in mucosa of bowel causing severe bloody diarrhoea (haemorrhagic colitis)

16-48 hours

• Bloody diarrhoea
• Crampy abdo pain
• May be fever

• Linked to HUS: haemolytic uraemic syndrome
• Renal failure
• Death

• In very young and very old: Cyto toxin damages RBC: haemolysis – red cell casts, blockage of renal tubules, tubular necrosis – renal failure so HUS
• In middle aged group: toxin hits platelet: TTP (thrombotic thrombocytopenic purpura)

• 1. Packaging industry at fault eg sausages
• 2. BBQ summer – school fete – person making burger is not a food handler (quick turnover of burgers – not cooked inside), cheap burgers contaminated with animal faecal organisms
• 3. Petting farms or zoo – inform CCDC – contact trace

• Norovirus (Norwalk virus/winter vomiting diseae)
• Calicivirus

Swallow virus: blunt or denude the absorptive surface of small intestine ie the villi, so decreased enzymatic activity. Get Lactose tolerant and malabsorptive diarrhoea. Transient malabsorption of fat due to decreased activity of enzymes in intestinal mucosa

12-24 hours

• Small round structured virus
• Non specific structure

• Frequent, projectile vomiting
• EXPLOSIVE diarrhoea – non bloody (as no invasion)
• Abdo cramps
• Low grade fever

• Diarrhoea
• Vomiting
• Fever
• Which foods are assoc with norovirus?
• Seafood – filter feeders
• Oysters, muscles – eaten raw or slightly sautéed

• Not amenable to alcogel
• There is no lipid coat around the virus. Non enveloped virus
• If have diarrhoea do not come to work as can spread esp COOP
• Need chlorine based deep clean

• Botulism
• Scrombotoxin
• Shellfish poisoning

• Clostridium botulinum
• Anaerobic organism

• Normal flora of human and animal dung is swallowed
• Germinates in gut
• Secretes toxin which enters blood stream and acts on neuromuscular junction: ACh receptor causing flaccid paralysis.

• Food borne – honey, very mild.
• Drug users or skin poppers get botulism as the drugs are contaminated with botulinum when made (eg in a cowshed contaminated with dung)

spores into skin – necrotic – anaerobic environment – great for replication of c.bot - toxin secreted enters bloodstream. Classic symptoms: cant speak as no control over facial muscles, cant smile or speak – slurred speech.

• Paralysis of resp muscles and diaphragm –
• need ITU – ventilator. Support from surrounding synapses
• Do survive

Because it is diluted millions of times. But same principle

Scromboid fish – dark meat fish: mackerel, tuna and parts of salmon, sardines, anchovies

Scromboid fish: Rich in histidine. When they go off – the histidine is broken down to histamine. So swallow large amounts of histamine when eat this gone off fish. As it is a vasoactive amine, histamine causes rash, tingling and numbness, light headed as vasodilatation, fall in BP. Anaphylactoid reaction

• anaphylaxis as is your own mast cells that are degranulating your own histamine limitlessly
• anaphylactoid is a finite amount of histamine you have swallowed and will easily denature

histamine

Piriton – anti histamine

Rotavirus

• 1. Respiratory tract
• 2. Rotavirus diarrhoea

Severe vomiting, diarrhoea, fever

• Faecal contamination of water
• Water transmission

Spokes of a wheel

• To tackle the rotavirus
• Oral rehydration therapy

• There is a vaccine
• Countries where poor water supply

• 1. Rotavirus: children killer
• 2. Norovirus: outbreaks
• 3. Astrovirus: less severe, hardly diagnosed as doesn't last for long enough to present
• 4. Adenovirus

• 1. Cryptosporidium
• 2. Giardia lamblia
• 3. Cyclospora
• 4. Entamoeba histolytica

AIDS patients prone to get severe intractable parasitic diarrhoeas especially cryptosporidium (now less with ARV)

• Acid fast
• Round organism
• Faecal organism

• 1. Immunocompromised: AIDS patients – intractable diarrhoea, not killed by amount of chlorine normally found in water. No 100% anti microbial treatment for it. So practically untreatable!
• 2. Immunocompetent: heavy rainfall or flooding lots of surface water from grazing fields containing animal faeces gets washed into reservoirs. Then cant drink tap water as normal chlorination of water does not get rid of cryptosporidium. Need to boil water then drink.

Public swimming pool as children pass faeces in there and chlorine cant get rid of crypto

Giardia lamblia.

Trophozoite. See flagellae

Crèche, nursery – children

Swallow cyst form – becomes trophozoite in gut – acts by blunting absorptive surface of small bowel.

Malabsorptive diarrhoea – frothy, smelly, fatty stool

Do not feed full strength milk – as villous processes still being regenerated. So not enough enzymatic activity to break down the lactose – takes a little time. Same for viral diarrhoea

• Send stool – find it
• Rx: metronidazole, or tinidazole (variant)

St Petersburg

• Nepal or brazil
• Not UK

• Poorly identified diarrhoea
• Flatulence, bloating, malabsorption.

Human faeces from patient to patient

• Not in UK
• Countries where use human faeces as fertiliser – salads contaminated

• Swallow cyst
• But severe invasive potential. Can produce large shaggy ulcers in large bowel

• 1. perforation
• 2. Trophozoites enter blood stream – travel up portal circulation and cause same destruction in liver – large liver abscess.

Metronidazole or tinidazole

Human faecal contamination of food and water (not so much animal faces)

• Invasive
• Secretory

• Organism invades into bowel mucosa – causes ulceration – blood in faeces
• Abdo pain
• Fever- inflammatory diarrhoea

• 1. Shigella
• 2. Enteroinvasive e.coli aka O157
• 3. Entero-aggregative E coli
• 4. Entero pathogenic E coli
• 5. Salmonella
• 6. Campylobacter

• 4
• Mildest in UK: shigella sonnei – common in public toilets. Only need to swallow 10 organisms and will get diarrhoea!

MSM – shigella sonnei

• Shigella dysenteriae
• Like E coli O157
• Causes same sequalae like HUS

same as shigella and get dysentery

shiga like entero-cytotoxin

causes attachment to and effacement of villous processes

young children in outbreaks

causes attachment and a mucus biofilm

• Cholera
• Entero-toxigenic e coli

• gram -ve
• comma shaped rods

• Swallow org
• Secretes toxin in gut – binds to receptor in gut mucosa – as soon as binds – the invasive proteins enter cell and take over regulation of cAMP.
• Increase cAMP and do not switch off so net movement of water and electrolytes from the enterocytes into the lumen (reversal of ATPase pump)

• Ricewater stool
• As purging own ISOTONIC FLUID
• Very little stool
• Flakes of mucus = rice

Dehydration, acute tubular necrosis

• Where safe water is a problem – contamination
• Refugee camps classically.
• Water stored in tanks. One case of cholera will spread

• Fluid replenishment
• Antibiotics: not to Rx the patient, but to decrease the load that comes out per ml of faeces! Eg ciprofloxacin or tetracycline – decrease the spread

E tec

• Acquired gene from cholera toxin
• Milder disease than cholera, recover faster in e tec

Yes but not very successful

• Clostridium difficile
• Anaerobic
• 5-10% of pop carry it in gut

• asymptomativ disease
• mild mod severe diarrhoea
• pseudomembranous colitis - need colectomy

G+ve anaerobe

• INFECTION CONTROL: ENTERIC CONTROL - side room. wear gloves and aprons, wash hands before and after soap and water
• 1. stop antibiotic
• 2. oral metronidazole (or iv or rectal)
• 3. ORAL (as does not leave gut into bloodstream) vancomycin if severe
• 4. if normal bowel - faecal enema (partners)
• 5. colectomy if pseudomembranous colitis and toxic dilatation

oral pro-biotics eg yeasts and lactobacilli

white plaques

• broad spectrum - normal flora changed
• all beta lactams: esp cephalosporins, clindamycin
• quinolones: ciprofloxacin

stool culture and drug susceptibility

PCR and EM on stool sample

stool stained microscopy

• stool sample
• look for toxin by immunochromatograph
• ELISA

• replace water and electrolytes
• antibiotics play not part in food borne diarrhoea
• self limiting illness
• best thing is to purge organism out of system

• must justify it
• 1. very young and very old
• 2. any underlying immunocompromise AIDS haematological malignancy
• 3. severe systemic toxicity - look sepsis, high WBC, organism in blood culture

• ciprofloxacin
• except if suspect campylobacter as 40% in UK are resistant to cipro

• erythromycin
• resistant as cipro was used to give chickens!

do not treat as higher risk they get HUS

• if you think you have toxic diarrhoea
• as run risk of toxic megacolon
• eg bloody diarrhoea don't take

ciprofloxacin