Lecture 16: Clinical Microbiology

Question 1

What did they think caused disease in pre-1850?

Answer 1

“Miasmatic theory”

1. Disease transmitted by miasma
2. ‘Poisonous vapour or mist’

Question 2

What was germ theory (post 1850)

Answer 2

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 

1. Propose microorganisms are cause of
   many diseases
2. highly controversial when first proposed

Question 3

Who was Robert Koch?

Answer 3

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

Question 4

How did we control infectious disease?

Answer 4

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

Question 5

What are the causes of death today?

Answer 5

1. 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

Question 6

What is diarrhoeal disease and how impactful is it?

Answer 6

1. Biggest cause of infant mortality world
   wide
2. Everyday ~200 million people have
   diarrhoea worldwide

Question 7

Why is infectious disease-related mortality not decreasing anymore?

Answer 7

1. Increase antibiotic resistance

2. New diseases

Question 8

Why has antibiotic resistance occured?

Answer 8

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

Question 9

What is an example of antibiotic misuse

Answer 9

1. Salmonella Typhimurium DT104
2. Enrofloxacin
3. licensed for animal use in 1993
4. outbreak in 1999/2000
5. Multidrug resistance

Question 10

What are some emerging infectious diseases

Answer 10

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

Question 11

How big of a problem is air travel for the spread of infectious diseases?

Answer 11

1. no city more than 24hours from
   another
2. ~500,000 people flying at any
   moment

Question 12

Outline the SARS outbreak

Answer 12

1. First global epidemic of 21st century

2. 8098 patients + 774 deaths

Question 13

Major factors behind emerging infectious diseases

Answer 13

pathogens ->