SL22105 PA-2 Bacterial Infections 2 2024 PDF

Specialised Integrated Unit 1 : Immunity, inflammation and infections and Gastrointestinal disease. Sl22105 PA-2 Bacterial infections 2 Dr Miriam Ellis Department of Pharmacy & Pharmacology  Bacterial Inf...

Specialised Integrated Unit 1 : Immunity, inflammation and infections and Gastrointestinal disease. Sl22105 PA-2 Bacterial infections 2 Dr Miriam Ellis Department of Pharmacy & Pharmacology  Bacterial Infections Respiratory tract Urinary Tract Sexually Transmitted Diseases Gastrointestinal Tract – Mouth – GI tract Infections ‘Food Poisoning’ Antibiotic associated C. diff infections Central Nervous System- Skin, bone and soft tissue Blood and heart  The GI tract. The mouth Dental infections Caries: Streptococcus mutans Abscess. Grows on plaque on teeth, Produces Lactic acid Infection from tooth-decay Cause tooth decay. spreads to underlying tissue Treatment Treatment Fillings/ extraction Can be treated with antibiotics (not antibiotics) Need dental treatment Damdent, Wikimedia Commons © Mayo Foundation for Medical Educaion and Research Peridontal disease Bacteria colonise crevice between the teeth and gums. (Gum disease): Gums inflamed, bleed recede Bacteroides, Teeth may fallout. Actinomyces Treatment Good oral hygiene (not antibiotics) Dr Agustín Zerón, Wikimedia Commons Opportunistic superinfections of the mouth Oral thrush: Candida albicans Imbalance in natural microflora of the mouth. Overgrowth of one micro- orgnanism. Seen in: Immunocompromised patients After Treatment with oral Centers for Disease Control and Prevention antibiotics/ long course of antibiotics James Heilman, Wikimedia Commons are eukaryotic – naturally resistant to antibiotics targeting prokaryotic  Gastrointestinal Tract Centers for Disease Control and Prevention Infections Viral * e.g. rotavirus Protozoa Parasites Common examples: Escherichia coli Bacterial Salmonella enterica Many species! Shigella Campylobacter *Most common Agricultural Research Service Will all produce slightly different symptoms Diarrhea is the most common symptom!  E. coli Centers for Disease Control and Prevention 700 different strains Gram Negative rod. Commonly lives in digestive tract and don’t cause disease! 200 strains can cause GI disease -Classed into 6 different groups based on epidemiology (way they cause disease) Enterohaemorrhagic E. coli (EHEC) e.g. H7 and 0157:H7 Bacteria bind to epithelial cells of large intestine. Produce toxins which act directly on these cells- they excrete fluid & cause diarrhoea Can cause haemorrhagic colitis and haemolytic-uraemic syndrome Symptom-Severe Bloody Diarrhoea Enterotoxigenic (ETEC) E. coli Bacteria bind to epithelial cells of small intestine Produce plasmid-associated toxins which act directly on these cells & cause diarrhoea (self limiting) ‘Travellers’ diarrhoea – important to treat with fluid replacement.  Salmonella enterica (i) Self-limiting diarrhoea * From raw meat, poultry, eggs, unprocessed milk S. enterica Enteritidis (abbreviated to Salmonella Enteritidis) S. enterica Typhimurium (abbreviated to Salmonella Typhimurium) Bacteria invade epithelial cells in terminal portion of small intestine. Induce inflammatory response which then causes diarrhoea. (ii) Systemic disease: typhoid fever From contaminated water S. enterica serovar Typhi, S. enterica serovar Paratyphi Bacteria penetrate gut mucosa, divide in macrophages, transported to lymph nodes and enter bloodstream where they infect many organs Causes fever & malaise which progresses to cause acute illness * Most common  Campylobacter Most common cause of diarrhoea in humans in UK Self-limiting diarrhoea Agricultural Research Service - From poultry, milk or water e.g. Campyobacter jejuni Clinically similar to self-limiting diarrhoea seen with salmonellae but sometimes has a longer incubation and longer duration Treatment rehydration and antibiotics (erythromycin) if required ‘Food Poisoning’ Bacterial toxins cause disease Food poisoning may also result from bacterial toxins present in food. Will cause symptoms with no bacterial infection. Bacteria are destroyed when food is properly cooked, but toxins may be resistant to heat and acid (in stomach). They cause the symptoms of food poisoning when they reach the small intestine. Diarrhoea (& vomiting) caused by food poisoning occurs rapidly after eating (within hours or sometimes minutes) of contaminated food Campylobacter jejuni (77%) Salmonella enterica (21%) E. coli 0157: H7 (1.4%) Clostridium botulinum – one of most powerful toxins known- causes paralysis Bacillus cereus - toxins in poorly stored food /reheated rice cause D&V S. aureus – toxins produce severe vomiting (no diarrhoea)  Antibiotic-associated diarrhoea Opportunistic superinfection following treatment with broad spectrum antibiotics →overgrowth by Candida albicans →overgrowth by Clostridioides difficile Rehani et al. 2007, J Med Case Reports, 1: 99 Klinikum Dritter Orden (München), Wikimedia Commons  Clostridioides difficile Most commonly diagnosed bacterial cause of HAI associated diarrhoea Obligate anaerobic, spore-forming bacteria, Klinikum Dritter Orden (München), resistant to many antibiotics Wikimedia Commons Spores are resistant to most disinfectants- and once on a ward it becomes difficult to remove. Can over-colonise gut when patient is treated with a broad spectrum antibiotic Found naturally in gut of some healthy individuals and can be spread by Health Care workers- spores are hard to kill and so easy to spread through a ward. Produces toxins which cause severe diarrhoea & abdominal cramps. Can progress, causing severe bloody diarrhoea, inflame intestine- Colitis pseudomembranous colitis and toxic megacolon, can lead to death Organism of concern due to increase in prevalence. https://www.youtube.com/watch?v=N2kXkgUN6wE  Infections of CNS: Bacterial meningitis Meningitis is an inflammation of the meninges –the membranes enveloping the brain. Causes (important to know what type to give effective Viral treatment) meningitis * most common & less severe Bacteria: Neisseria meningitidis* - most common in children < 5’s, or 18-25’s 80% of all cases in UK Streptococcus pneumoniae – most common in 60’s. (very young/ elderly immuno-compromised) very dangerous- 20% mortality with treatment. Haemophilus influenza (Type B) most common in patients Approx Respirat 6% of patients ory Tract 28 500 patients , died from Clinical HAI sepsis HAI is one of the biggest killers Urinary Surgical Tract in developed countries site 13,900 HCAI in health care professionals 6 most common sites of HAI 2017 Guest JF, Keating T, Gould D, et al. Modelling the annual NHS costs and outcomes attributable to HCAI in England. BMJ Open 2020;10:e033367. doi:10.1136/ bmjopen-2019-033367 Why do people acquire infections in a hosptital/ health care setting?  HAI: 5 organisms of concern for the NHS: fact Files Clostridioides difficile E. coli – Causes severe diarrhoea. Lives in your The most common cause of UTIs in gut- hospitals. Forms spores-Highly persistent can (Huge problem particularly amongst remain dormant on the hospital ward. catheterised patients) Outbreaks can cause closure of wards Klebsiella pneumonia- Causes a variety of HAI-pneumonia, MRSA- Antibiotic resistant bloodstream infections, wound or Staphylococcus aureus surgical site infections, and meningitis. Commensal bacteria which lives on It doesn’t usually affect healthy people. your skin- Problem for those catheterised, on a Can cause skin infections- ventilator, on long term antibiotics In hospital causesing wound infections. -MRSA now prevalent Pseudomonas aeruginosa– What is CRE? Gram negative opportunistic pathogen – CRE: Carbopenem Resistant common in soil and water Enterobacteriaceae Causes respiratory and blood stream Antibiotic resistant forms infections in those who are already sick E.coli and Klebsiella are members of the or immune compromised. family Enterobacteriaceae ( Gut living) Multidrug resistant strains. CRE-forms of both are a Huge problem in hospital  Bacterial Infections Respiratory tract Urinary Tract Sexually Transmitted Diseases Gastrointestinal Tract – Mouth – GI tract Infections ‘Food Poisoning’ Antibiotic associated C. diff infections Central Nervous System- Meningitis Skin, bone and soft tissue- Cellulitis - leads to secondary infection Blood and heart- Endocardidtis / Sepsis HAI – a huge problem – affects high proportion of in patients. Also effects staff