Microbial Infection

Question 1

What is bacteria?

Answer 1

A prokaryote
Have poorly define cytoskeleton
Have flagellum for mobility
E.g. mycobacterium TB, Neisseria meningitidis

Question 2

What can be found in the cell walls of bacteria?

Answer 2

Peptidoglycans

Question 3

How does bacteria replicate?

Answer 3

Binary Fission

Question 4

What is a virus?

Answer 4

An obligate parasite
Contain RNA or DNA
E.g. HIV, Smallpox, Polio, HPV

Question 5

How are viruses transmitted?

Answer 5

Blood, airbourne vectors, faecal-oral

Question 6

How do viruses replicate?

Answer 6

Use host cell machinery

Divide by budding out of host cell

Question 7

What are fungi?

Answer 7

Single cell eukaryotes
Includes yeasts and filaments
E.g. Candida Albicans

Question 8

How does fungi replicate?

Answer 8

yeast buds or divides

filaments extend

Question 9

What are protezoa?

Answer 9

Unicellular eukaryotic organisms
Many have lifecycle including 2 hosts
E.g. Plasmodium falciparum, Leishmania Spp.

Question 10

How is protozoan infection transmitted?

Answer 10

vector transmission or ingestion

Question 11

How does protozoa replicate?

Answer 11

In host by binary fission or by formation of trophozoites inside cell

Question 12

What are helminths?

Answer 12

Multicellular eukaryotes
They’re worms: Flatworm, roundworm, tapeworm
Have lifecycles outside human host
E.g. schistosoma Spp.

Question 13

How do helminths replicate?

Answer 13

Sexally- adult produces shedding eggs

Question 14

What is Neisseria Meningitidis?

Answer 14

Gram negative diplococci- bacteria
Lives harmlessly in 20% of population but can become hostile
Nose and throat commensals
Has rapid onset

Question 15

What are symptoms of Neisseria Meningitidis?

Answer 15

non-blanching rash, septicaemia, blocked blood vessels, can penetrate blood-brain barrier and cause meningococcal meningitis

Question 16

What is mycobacterium TB?

Answer 16

Bacteria
Intracellular rod
Causes TB
Respiratory disease but can be systemic
BCG vaccine doesn't work well in endemic regions
Very hard to treat, can be lifelong

Question 17

What is Shigella?

Answer 17

Bacteria
Has no flagella but moves using actin to push itself between cells
Infects the GI tract and in severe cases can lead to huge amounts of tissue damage and cause death
Faecal-oral transmission
Lots of blood diarrhea

Question 18

What is HIV?

Answer 18

ssRNA Virus
Uses reverse transcriptase to turn RNA to DNA
Infects T- cells- very low CD4 count increases risk of infection
Leads to AIDS

Question 19

What causes smallpox?

Answer 19

Variola Virus

Question 20

What is Candida Albicans?

Answer 20

Fungi
Combination of yeast and filaments
Natural yeast in our bodies- commensal of mouth and skin but opportunistic
Can cause candidiasis (thrush)

Question 21

What is plasmodium falciparum?

Answer 21

Protozoa
Mosquito vector
Infects liver and affects blood cells ability to develop
Forms trophozoites inside cells
People with sickle cell and B- thalassaemia can’t get malaria

Question 22

What are symptoms of a plasmodium falciparum infection?

Answer 22

Fever
Headache
Anaemia
Hepatosplenomegaly
Jaundice

Question 23

What is Leishmania Spp.?

Answer 23

Protozoa
Infection acquired via sandfly
Replicates in blood, immune cells and other tissues
Replicated by binary fission
Has 3 forms: cutaneous, mucosal and visceral
Can cause leishmaniasis: lesions, hepatosplenomegaly

Question 24

What is Schistosoma Spp.?

Answer 24

Helminth
Is a flatworm
Intermediate vector is a snail
3 main types of schistosoma can be transmitted when people enter contaminated water
Adult lives in hepatic portal vein of humans
Produces spirey eggs which allows them to enter gut