Infection Session 1- Infection And Microbes Introduction

Question 1

What is an infection?

Answer 1

Invasion of a host’s tissues by micro organisms and disease caused by microbial multiplication, toxins and host response

Question 2

State 3 ways a person can get an infection

Answer 2

Patient to patient contact
Animals
Intermediary
Environment (water, food, air, surfaces)

Question 3

Define microbiota

Answer 3

Normally harmless micro organisms carried on skin and mucosal surfaces transfer to other sites and can be harmful

Question 4

Name 3 modes of horizontal transmission

Answer 4

Contact
Inhalation
Ingestion

Question 5

How does vertical transmission take place?

Answer 5

Mother to child before or after birth

Question 6

How do microorganisms cause disease?

Answer 6

Virulence factors

Host cellular damage

Question 7

How do we determine if a patient has an infection? (3 steps)

Answer 7

History
Examination
Investigations

Question 8

Give 3 examples of supportive investigations

Answer 8

Full blood count
CRP
Liver and kidney function tests
X-Ray
Ultrasound
MRI

Question 9

How do we test specifically for a bacterial infection?

Answer 9

1. Sample (swab/ fluid/ tissue)

2. Microscopy, culture, antibiotic susceptibility

Question 10

How do we test specifically for a viral infection?

Answer 10

Antigen detection
Antibody detection
Detecting viral nucleic acid

Question 11

Name the 4 different types of microbe

Answer 11

Virus
Bacteria
Parasites
Fungi

Question 12

What are the 4 main structural features of a virus?

Answer 12

Envelope (may or may not be present)
Protein coat
Nucleic acid (DNA or RNA, single or double stranded)
Spikes (for attaching to specific cell surfaces)

Question 13

Give an example of a single stranded, non enveloped DNA virus

Answer 13

Parvovirus 19

Question 14

Give an example of a double stranded, non enveloped DNA virus

Answer 14

Adenovirus

HPV

Question 15

Give an example of a double stranded, enveloped DNA virus

Answer 15

Herpes
Hep B
Molluscum

Question 16

Give an example of a single stranded, +ve strand, icosahedral, non enveloped RNA virus

Answer 16

Echovirus
Hep A
Hep E
Norovirus

Question 17

Give an example of a single stranded, +ve strand, icosahedral or helical, enveloped RNA virus

Answer 17

HIV
Hep C
Rubella

Question 18

Give an example of a single stranded, -ve strand, helical, enveloped RNA virus

Answer 18

Ebola
Measles
Mumps
Influenza

Question 19

Give an example of a double stranded, icosahedral, non enveloped RNA virus

Answer 19

Rotavirus

Question 20

What is the main type of bacteria that cause human disease?

Answer 20

Eubacteria (true bacteria)

Question 21

What is the difference in the cell wall of gram +ve and gram -ve bacteria?

Answer 21

\+ve = thicker peptidoglycan
-ve = thinner peptidoglycan and lipopolysaccharide present

Question 22

Give an example of gram +ve cocci

Answer 22

Staph aureus

Streptococcus pneumoniae

Question 23

Give an example of gram +ve bacilli

Answer 23

Bacillus anthacis

Bacillus cereus

Question 24

Give an example of gram -ve cocci

Answer 24

Neisseria meningitidis

Neisseria gonorrhoeae

Question 25

Give an example of gram -ve bacilli

Answer 25

E. Coli

Salmonella typhi

Question 26

What are the 2 types of fungi? Give examples of each

Answer 26

Yeasts (single celled) eg. Candida albicans, cryptococcus neoformans
Molds (multicellular) eg. Aspergillus species, dermatophytes

Question 27

What are the 2 types of parasites? Give examples of each

Answer 27

Protozoa (single celled) eg. Plasmodium falciparum

Helminths (worms, multicellular) eg. roundworms, tapeworms, flukes