Gastrointestinal Infections (2.8) PDF

Bristol Stool Chart 1 Bristol Stool Chart | NHS  Risk groups A Doubtful personal hygiene; unsatisfactory facilities B: Children aged five years old or under C: Food handlers D: Clinical, social care or nursery staff Consult guidelines...

Bristol Stool Chart 1 Bristol Stool Chart | NHS  Risk groups A Doubtful personal hygiene; unsatisfactory facilities B: Children aged five years old or under C: Food handlers D: Clinical, social care or nursery staff Consult guidelines which suggest how to deal with risk groups differently 2  Stool sample collection Collect a stool sample using a clean, sterile container, ensuring no contamination with urine or water. Seal the container securely, label it with your details, and deliver it to the lab as soon as possible, usually within 24 hours.  MC&S: Culture For an MC&S (Microscopy, Culture, and Sensitivity) test, a sample (e.g., stool, urine, or swab) is collected using sterile techniques, placed in an appropriate transport medium, and sent to the lab promptly to ensure accurate microbial analysis. 4  PCR vs culture Culture Whole organism: The growth of viable organisms indicates active infection PCR Genetic material: active infection vs recovering/recovered Can identify presence of certain toxins Could represent a more virulent infection 5  Campylobacter (1) The most common bacterial cause of human gastroenteritis in the world. Commonest bacterial cause of GI infection in the UK One of most common causes of traveller’s diarrhoea in UK Source: undercooked meats, contaminated water, animal contact Low risk of person-to-person spread 6  Campylobacter (2) Generally mild illness Can be fatal – very young, elderly, immunosuppressed Diarrhoea, abdominal pain, fever Less common: bloody diarrhoea, vomit Lasts 2-3 days No active public health management of sporadic cases As no person-to-person transmission Animal PH authorities involved if there are clusters – may indicate issues with poultry 7  Cryptosporidiosis Cryptosporidium parasite Contact with animals, person to person, contaminated water Outbreaks: public water supplies, swimming pools Profuse watery diarrhoea, abdominal cramps, vomiting, fever Last 10-14 days if healthy Immunocompromised – chronic diarrhoea, life-threatening 8 9  Enteric fever (typhoid, paratyphoid) Salmonella typhi and paratyphi – same symptoms and management Serious disease, life-threatening High fever, abdominal pain, headache, constipation/diarrhoea Antibiotics Lasts several weeks Predominantly acquired abroad: contaminated food / water Highly contagious Travel vaccine available (not perfect in typhi, ineffective for paratyphi) Microbiological clearance if in risk group Three negative samples, 48hr apart, a week after antibiotics 10  Giardiasis Giardia lamblia Person-to-person spread common, waterborne, animal contact Outbreaks: infected food handlers, swimming pools Diarrhoea, greasy stools, abdominal pain, flatulence, Can last 6 weeks Antibiotic treatment Cysts (excreted in stool) are resistant to chlorination No swimming for 2 weeks after recovery 11  Hepatitis A Person-to-person spread, foreign travel contaminated food/water Sexual intercourse (e.g. MSM), injecting drug abuse Symptom severity increases with age; 90% asymptomatic 2500 serotypes of Salmonella Can be used to trace where infections have come from (WGS) E.g. salad farms, frozen mice used to feed snakes 17  Shigella (bacterial dysentery) Diarrhoea (watery, slimy, or bloody), fever, abdominal cramps Shigella sonnei, boydii, dysenteriae, flexneri Shigella sonnei: mild illness Illness lasts one day to 1-2 weeks Spread: person-to-person, environment-to-person, sexual contact – MSM foreign travel – contaminated food/water Antibiotic treatment Microbiological clearance (1 negative stool 18 sample)  Shiga toxin producing Escherichia coli (STEC) Mild gastroenteritis, severe bloody diarrhoea, haemolytic uraemic syndrome (HUS), death HUS: kidney failure, thrombotic thrombocytopaenic purpura Main reservoir: cattle, other ruminants (goat, sheep, deer, giraffes) Low infectious dose, from… Consumption of contaminated food or water Direct or indirect contact with animals or their faeces 19 Person-to-person spread (usually young children)  Escherichia coli [The Gajraj classification*] Good E. coli Gut flora. (But note can cause UTI) Naughty E. coli Don’t produce Shiga toxin Diarrhoea – usually mild and self-limiting Evil E. coli: STEC O157 O26, O123, O113, O88, O55, O9, O37, O38, O78, O114, O146, O156, O174, O183, etc 20 Diarrhoea OR severe GI infection OR HUS/death