Infection, Normal Flora, Infectious Agents

Question 1

Describe:

• Saprophytes
• Commensals include examples
• Opportunistic pathogens include examples
• True Pathogens

Answer 1

Saprophytes: Are plant, fungi or microorganism that lives off dead or decaying matter.

Commensals is deemed a ‘normal flora’
e.g: Staphylococcus epidermidis, Candida albicans, Escherichia coli.

Opportunistic pathogens: is normally commensal but not always and cause disease when the opportunity arises. e.g: S.epidermidis, C.albicans, E.coli.

True pathogen: Causes disease in virtually any susceptible host.
e.g: S.aureus, N.gonerrheae, Covid-19

Question 2

Define:

• Infection

- Infectious disease (communicable disease)

Answer 2

Infection: process of microbial invasion eg. common cold, tonsillitis, UTI, infected leg ulcer.

infectious disease: infective diseases that are readily transmitted from person to person. eg. respiratory infections (eg. TB, Common cold, Covid-19, GI infections, STI’s).

Question 3

Infection in the 21st century: Developed nations.

6 infections of concern in the developed world.

Answer 3

1. Pneumonia: HAP/CAP 30,000 deaths PA in uk.
2. Tuberculosis: (10 mil new cases PA) and drug resistance TB (560K new cases PA) globally.
3. GI infections (norovirus, campylobacter, C.difficle
4. Device-related infections (catheters, prosthetic joints).
5. Healthcare associated infections: (MRSA, C.difficle, Carbapenemase-producing G-ve).
6. Sexually Transmitted infections (Chlamydia, gonerrhea, sphyilis, herpes, genital warts, HIV).

Question 4

Infection in the 21st century: developing nations.

6 infections of concern in the developing world.

Answer 4

Asia and sub-Saharan Africa.

1. HIV 70% the worlds HIV burden, 70% of all new HIV infections.
2. AIDS: 80% of AIDS related deaths
3. Malaria: 90% of the global malaria burden
4. TB 40% of all new TB cases.
5. Diarrhoeal Disease: (parastic, bacterial, viral).
6. Ebola.

Question 5

Name some bacteria:

• Gram Positive Cocci
• Gram positive bacilli (aerobic and anaerobic)
• Gram negative cocci
• Gram negative aerobic bacilli
• Gram negative anaerobic bacilli

Answer 5

Gram + cocci: Staphylcoocus eg. S.aureus, MRSA, S.epidemidis & Streptococcus eg. S.pyrogenes, S.pneumoniae.

Gram + Bacilli Aerobic: Bacillus anthracis
Gram + Bacilli Anaerobic: Clostriodies difficle

Gram - Cocci: N.gonerrheae

Gram - aerobic bacilli: - Enterobacteria: (E.coli) Psudomonads: (P.aeruginosa) Parvobacteria: (H.influenzae) Vibrios: (Campylobacter)

Gram - Anaerobic Bacilli: Bacteroides sp.