L1 Intro to Medical Bacteriology

Question 1

Features of bacteria

Answer 1

• Small
• Unicellular
• Prokaryotic (no compartmentalisation)
• Diverse
• Ubiquitous

Question 2

Bacteria being useful…

Answer 2

• Ecosystem
• Source of useful compounds
• Food production

Question 3

Bacteria being bad…

Answer 3

• Used in destructive processes e.g. disease
• Food spoilage
• Biofouling and corrosion

Question 4

What % of human diseases are caused by bacteria?

Answer 4

35% (538 species)

Question 5

Infectious disease in today’s society

Answer 5

Top 3 deaths in industrial population were all bacterial infections, but medical intervention has improved this

Question 6

Koch’s postulates

Answer 6

DEMONSTRATES CAUSE AND RELATION TO SPECIFIC DISEASES

1. Microorganism must be present in every case of the disease (not within healthy animals)
2. Microorganism must be isolated from diseased host and grown in pure culture
3. Specific disease must be reproduced when a pure culture of microorganism is inoculated into healthy susceptible host
4. Microorganism must be recoverable from experimentally infected host and shown to be identical to original causative agent

Question 7

Types of bacteria in disease (3)

Answer 7

• Pathogenic: only a small %
• Opportunistic: only cause disease in predisposed conditions e.g. illness
• Non-pathogenic: don’t cause disease

Question 8

Site of infection

Answer 8

Can be superficial or within body and is more common on certain sites e.g. skin compared to stomach

Question 9

Why is it difficult to get specimen only from the body?

Answer 9

Provides colonisation resistance and includes numerous conditional pathogens

Question 10

Endogenous infections

Answer 10

Result from microbiome initiating infection e.g. skin infection and UTIs

Question 11

Exogenous infections

Answer 11

Coming from outside of the body e.g. during food poisoning

Question 12

What is zoonosis?

Answer 12

When an infectious disease can be transmitted from animal to a human

Question 13

Examples of zoonotic human pathogens

Answer 13

• Anthrax
• Campylobacteriosis
• E.coli
• Plague (Yersina pestis)

Question 14

What organism causes Tuberculosis?

Answer 14

Mycobacterium tuberculosis

Question 15

Where is Tuberculosis primarily an infection of?

Answer 15

Lungs

Question 16

Symptoms of Tuberculosis

Answer 16

-Cough
-Chest pain
-Fever
-Weight loss
-Fatigue
(symptoms only shown in active infection - not in latent infection)

Question 17

What does Tuberculosis lead to?

Answer 17

Granuloma formation (spherical bundle of immune cells aggregated)
Necrosis (cell death)
Fibrosis (tissue scarring)

Question 18

Statistics about Tuberculosis

Answer 18

-1/3 world’s population are latently infected
-1/10 latent infections become active
-Untreated active kills 1/2
Increased transmission where reduced medical care and overcrowding

Question 19

What organism is pneumonia caused by?

Answer 19

Streptococcus pneumonia’s

Question 20

Symptoms of Pneumonia

Answer 20

• Cough
• Fever
• Chest pain

Question 21

Consequences of pneumonia

Answer 21

O2 transport through alveoli is compromised and leakage of bacteria occurs into bloodstream

Question 22

What is a major cause of human disease?

Answer 22

Synergy between viral and bacterial disease
e.g. influenza and bacterial pneumonia
HIV and TB

Question 23

Influenza and bacterial pneumonia synergy

Answer 23

Viral disruption of bronchial and lung cells

Question 24

HIV and TB synergy

Answer 24

HIV individuals are 800x more likely to develop active TB

Question 25

Foodborne infection

Answer 25

Don’t 100% know definite numbers as majority aren’t reported:
1 million cases per year in UK
20,000 hospital admissions
500 deaths

Question 26

Types of food borne bacterial disease

Answer 26

• Infectious: Campylobacter (zoonotic associated with poultry)
• Toxic mediated: driven by organism growing in food that we’ve eaten, ingesting heat stable toxin which causes effects

Question 27

Methods of prevention and treatment of bacterial diseases

Answer 27

• disinfection/ sterilisation
• aseptic techniques
• decolonisation and prophylactic antibacterial
• vaccination
• antibacterial chemotherapy
• anti-toxin
• other e.g. surgery, electrolyte replacement