Introduction to Medical Microbiology

Question 1

Where can you find infection?

Answer 1

Essentially everywhere. This can include:
Intensive care 
General Practice 
Children 
Haematology and Oncology patients 
Hospital acquired infection (HAI)

Question 2

State the categories of microorganism that cause disease

Answer 2

Bacteria 
Viruses 
Fungi 
Parasites 
Prions

Question 3

State the sterile specimen types

Answer 3

Blood
Bladder
Cerebrospinal fluid (CSF)
Lung

Question 4

State the non-sterile specimen types

Answer 4

Skin
Urethra
Nasopharynx
Gut

Question 5

State what is meant by the term ‘sterile’

Answer 5

Containing no microorganisms

Question 6

State the specimen type collected for bacterial culture:

Urinary tract infection

Answer 6

Mid-stream urine (MSU)

Question 7

State the specimen type collected for bacterial culture:

Chest infection

Answer 7

Sputum

Question 8

State the specimen type collected for bacterial culture:

Tonsillitis/pharyngitis

Answer 8

Throat swab

Question 9

State the specimen type collected for bacterial culture:

Wound

Answer 9

Swab or pus

Question 10

State the specimen type collected for bacterial culture:

Diarrhoea

Answer 10

Faeces

Question 11

State the specimen type collected for bacterial culture:

Bacteraemia

Answer 11

Blood culture

Question 12

State the specimen type collected for bacterial culture:

Meningitis

Answer 12

Cerebrospinal fluid (CSF)

Question 13

Explain the role of microscopy and culture in the diagnosis of bacterial infection

Answer 13

Microscopy allows for the staining and rapid detection (not identification) of bacteria in a sample. However it is insensitive.
Culturing allows the bacteria to grow overnight on a specific medium. After incubation, the colonies are visible to the naked eye. Stains can then be identified by colonial appearance and growth patterns.

Question 14

Unstained microscopy is done to view

Answer 14

Pus cells (Urine, CSF)
Parasites (faeces)

Question 15

Gram stain microscopy is done to view

Answer 15

Bacteria and yeast/fungi

Question 16

ZN/auramine stain microscopy is done to view

Answer 16

Mycobacteria

Question 17

State the type microorganism of that cannot be seen under the light microscope

Answer 17

Viruses

Question 18

Describe gram staining and microscopy

Answer 18

It is rapid, NOT sensitive and cannot usually identify a particular species

Question 19

Describe bacterial culture

Answer 19

It is slow, sensitive and the culture conditions are suitable for expected species

Question 20

How do you identify a species?

Answer 20

Use observable characters (biochemical, morphological and physiological)

DNA based tests

Question 21

Describe the methods of detecting viruses.

Answer 21

Virus can only grow/divide inside other cells/the host cell. Therefore a cell line must be inoculated.
Electron microscopy is used to due small size of viruses.
Antigen detection and nucleic acid amplification is more widely used to diagnose (serology less common)

Question 22

Describe the diagnostic principles in parasitology

Answer 22

• Cell cultures rarely possible for parasites
• Serology can sometimes be useful
• Microscopy of different stages can help to understand the parasites easier

Question 23

Describe basic infection control measures

Answer 23

Wash hands before touching patients/in between touching different patients.

Use of alcohol gel as well.

Swab stethoscope between patients

Wear plastic apron AND dispose when finished

etc