Gastrointestinal Infections PDF

Gastrointestinal Infections Saran Shantikumar Associate Clinical Professor, Public Health With thanks to Dr Roger Gajraj, UKHSA West Midlands Warwick University 2024  Learning outcomes 1. Outline principles of public health management of gastrointestinal (GI) infections 2. Ide...

Gastrointestinal Infections Saran Shantikumar Associate Clinical Professor, Public Health With thanks to Dr Roger Gajraj, UKHSA West Midlands Warwick University 2024  Learning outcomes 1. Outline principles of public health management of gastrointestinal (GI) infections 2. Identify key GI pathogens 2  Amoebiasis Histamine Poisoning (scombrotoxin) Bacillus Listeriosis Botulism Marine biotoxins Campylobacteriosis Norovirus Cholera Rotavirus Clostridium difficile Salmonellosis Clostridium perfringens Sapovirus Cryptosporidiosis Shiga toxin producing Escherichia Coli Cyclosporiasis Shigellosis Non-STEC Escherichia coli Worm Infestation Enteric Fever Vibriosis Giardiasis Worm infestation Hepatitis A Yersiniosis Hepatitis E 3  General principles Identify source Identify mode of transmission – defines control measures Diarrhoea: greater contamination and risk of spread Enteric precautions Risk groups Stool sampling Exclusion 4 48 hours or microbiological clearance (negative stool samples)  Common symptoms What could be the symptoms of gastrointestinal infections? 5  Bristol Stool Chart 6 Bristol Stool Chart | NHS  Transmission of gastrointestinal infections How could GI infection be spread? 7 Primary Prevention Food safety – “Farm to fork”, Milk pasteurisation Water quality – filtering and disinfection Public awareness – Open farms, summer BBQ, lambing season Foreign travel – advice on food/water use, vaccines 8  Food safety and hygiene: how to stay safe At home Cooking your food Chilling Cleaning Cross-contamination Buying and eating food Food hygiene ratings Best before and use-by dates Visiting open farms Lambing season and pregnant women 9  Food hygiene law Businesses responsible for complying with food hygiene law Hazard Analysis and Critical Control Point (HACCP) Review business: what could go wrong, what risks to food safety Identify critical control points to ensure risks removed or reduced to safe levels Decide action necessary if something goes wrong Ensure procedures followed and working Keep records to show procedures working 10  Food hygiene rating scheme Inspections How safely the food is handled in practice e.g. food storage, handling, preparation The premises: overall cleanliness, facilities, layout Measures to maintain hygiene standards: e.g. internal systems & policies Frequency of inspections Depends on the potential risk to public health: Type of food Number and type of customers, e.g. vulnerable groups Types of processes before food sold or served Hygiene standards at last inspection 11  Enteric precautions advice Personal hygiene Environmental cleaning Disposal of soiled materials 12  Personal hygiene: hand washing Hand washing (hand hygiene) The single most important method of preventing & controlling spread of infection NHS Hand Washing Poster 13  Personal hygiene: hand washing (2) Wash hands thoroughly with warm running water & soap: Before eating or before handling, preparing or serving food After using the toilet, changing a baby’s nappy, attending to anyone with D&V After handling or washing soiled linen, cleaning the toilet or child’s potty After contact with animals Dry hands thoroughly after washing Disposable paper towels/dedicated towel Supervise young children or others (e.g. learning disability) 14  Environmental cleaning Toilet and bathroom areas Spillages Soiled linen or clothing Using gown, gloves Disposal of soiled materials 15  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 16 17  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. 19  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 20  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 21  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 22  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 23 24  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 25  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 26  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 32  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 33 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 34 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 35 Diarrhoea OR severe GI infection OR HUS/death  www.kahoot.it 37