Lecture 16: Clinical Microbiology

“Miasmatic theory” • Disease transmitted by miasma • ‘Poisonous vapour or mist’

Louis Pasteur (1822-1895) a. Developed pasteurisation in 1864 b. PROVED SPONTANEOUS GENEROUTION DIDNT OCCUR c. showed that things could be contaminated e.g., food • Propose microorganisms are cause of many diseases • highly controversial when first proposed

• founder of public health • developed - “Koch’s Postulates” • Late 1800s discovered causal agents of: a. tuberculosis b. Cholera c. Anthrax

• Vaccination - big impact on mortality a. E.g., Small pox vaccination (1950s) • Antibiotics a. Pneumonia - penicillin, sulfia • Public health measures a. sanitation b. sewage supplies c. water supplies d. failure to follows things often leads to outbreaks • Social measures a. better housing b. reduction of poverty + over-crowding

• Bacterial disease: 8 million / year a. 47% lower respiratory tract infections b. 20% TB c. 22% Diarrhoeal - 1.8 million; 2/3 kids d. 11% Other

• Biggest cause of infant mortality world wide • Everyday ~200 million people have diarrhoea worldwide

• Increase antibiotic resistance 2. New diseases

• Pressure on doctors and patients to prescribe when not needed • Prescription of antibiotics without doctor knowing cause of infection • Use of antibiotics in animals for growth promotion and prophylaxis

• Salmonella Typhimurium DT104 • Enrofloxacin • licensed for animal use in 1993 • outbreak in 1999/2000 • Multidrug resistance

• Viruses a. Ebola b. COVID c. H5N1 flu (bird flu) d. H1N1 flu e. SARS virus f. West Nile Virus • Bacteria a. Plague b. MDR salmonella c. Clostridium difficile d. TB

• no city more than 24hours from another • ~500,000 people flying at any moment

• First global epidemic of 21st century 2. 8098 patients + 774 deaths

pathogens ->