Medical Microbiology

Question 0

What is meant by contamination?

Answer 0

The presence of an organism in a culture that was not present in the original sample

Question 1

Define the term medical microbiology

Answer 1

The study of microorganisms which are of medical importance and capable of causing diseases in humans

Question 2

What is meant by colonisation?

Answer 2

The presence of an organism at a site, not causing tissue reaction or disease
(ie. Normal flora)

Question 3

What is meant by infection?

Answer 3

When organisms invade a body site and initiate a tissue reaction (symptoms)

Question 4

What is the most basic way of classifying bacteria?

Answer 4

Based on what they look like under a microscope. -shape and gram staining

Question 5

What colour do gram positive bacteria appear when stained?

Answer 5

Purple

Question 6

What colour do gram negative bacteria appear when stained?

Answer 6

Pink

Question 7

Why are gram positive cells a different colour?

Answer 7

Because they contain more peptidoglycan in their cell walls

Question 8

Describe the gram staining process

Answer 8

1. Stain the slide with crystal violet
2. Flood the slide with iodine
3. Wash the slide with acetone (for 2-3seconds)
4. Stain with safranin counter-stain
5. View under the microscope

Question 9

Give an example of a gram negative rod

Answer 9

E.coli

Question 10

The characteristic shape and arrangement of Streptococci is what?

Answer 10

Gram positive cocci in pairs

Question 11

Gram positive cocci arranged in bunches is characteristic of what type of bacteria?

Answer 11

Staphylococcus

Question 12

Describe the stages in the chain of infection

Answer 12

1. Means of entry
2. Susceptible host
3. Infectious agent
4. Reservoir
5. Means of exit
6. Mode of spread

Question 13

What are some of the typical symptoms of infection?

Answer 13

Pain
Redness
Swelling 
Tachycardia
Confusion
Pyrexia
Pus production

Question 14

What are the three methods of decontamination?

Answer 14

Cleaning
Disinfection
Sterilisation

Question 15

What is low-risk equipment?

Give an example

Answer 15

Items that are in contact with healthy, intact skin, or not in contact with the patient

Wheelchairs and infusion pumps

Question 16

What level of decontamination is used for low-risk equipment?

Answer 16

Cleaning

Question 17

What level of decontamination is used for intermediate-risk equipment?

Answer 17

Disinfection

Question 18

What level of decontamination is used for high-risk equipment?

Answer 18

Sterilisation

Question 19

What is intermediate-risk equipment?

Answer 19

Items that are in contact with mucous membranes, contaminated with body fluids or are to be used on an immuno-compromised patient

Question 20

What is high-risk equipment?

Give an example

Answer 20

Items that are in contact with broken skin, mucous membranes or are introduced into a sterile body cavity

Surgical instruments

Question 21

In order to differentiate between colonisation and significant infection, what can be counted?

Answer 21

The number of bacteria in a urine sample

Question 22

How many patients are estimated to die from a healthcare associated infection every year?

Answer 22

5,000

Question 23

What are the standard precautions for infection prevention in a hospital setting?

Answer 23

Hand washing
Environmental cleaning
Patient isolation
Sharps management
Use of PPE

Question 24

What percentage of patients are likely to acquire an infection while in hospital?

Answer 24

10%

Question 25

Which part of the body is most heavily colonised by bacteria?

Answer 25

The gastrointestinal tract

Question 26

An elderly patient from a care home being admitted for a hip replacement should have what?

Answer 26

A nasal swab to test for MRSA

Question 27

What is the most appropriate method to decontaminate physically soiled hands?

Answer 27

Wash hands with soap and water and then use alcohol hand gel