Quiz 4

Question 1

Aminoglycosides act on DNA synthesis.

Answer 1

FALSE

Question 2

All bacteria have lipopolysacharide (endotoxin) in their cell walls.

Answer 2

FALSE

-Only gram negative organisms have endotoxin in their cell wall.

Question 3

Light microscopy can be used in the routine laboratory to examine unstained specimens of urine and cerebrospinal fluid (CSF) for the presence of pus cells (white blood cells).

Answer 3

TRUE

Question 4

An organism which is sensitive to an antibiotic will always be killed by it.

Answer 4

FALSE

Question 5

Penicillin allergic patients may also be allergic to cephalosporins.

Answer 5

TRUE

Question 6

Light microscopy can be used in the routine laboratory to screen faeces for the presence of vires.

Answer 6

FALSE

-Viruses can only be seen by electron microscopy.

Question 7

Third generation cephalosporins (eg, ceftazidime) have better anti-staphylococcal activity than the earlier cephalosporins

Answer 7

FALSE

Question 8

Concerning diagnostic methods: direct immunofluorescence can be used to identify specific organisms in clinical material.

Answer 8

TRUE

Question 9

Pasteurisation results in sterilisation of milk.

Answer 9

FALSE
-Pasteurization can be used on many other liquids (eg plasma) but it will only reduce the bacterial load, not sterilize the liquid.

Question 10

All bacteria have lipopolysaccharide (endotoxin) in their cell walls.

Answer 10

FALSE

-Only Gram negative organisms have endotoxin in their cell wall.

Question 11

Malaria is never passed from human to human.

Answer 11

FALSE

-Malaria can be transferred via blood transfusion.

Question 12

Amphotericin B treatment should not be started until laboratory sensitivity results are available.

Answer 12

FALSE

Question 13

Concerning diagnostic methods: A single elevated IgM titre is generally acceptable as serological proof of infection.

Answer 13

TRUE

-IgM represents the acute response and therefore suggests current infection.

Question 14

Prophylaxis should be given before every operation.

Answer 14

FALSE

Question 15

The complement fixation test detects killed virus in the patients blood.

Answer 15

FALSE

Question 16

Gentamicin is associated with ototoxicity, and all aminoglycosides are ototoxic.

Answer 16

TRUE

Question 17

Trimethoprim interferes with protein synthesis at the ribosomal level.

Answer 17

FALSE

Question 18

Concerning diagnostic methods: a single elevated IgG titre is generally acceptable as serological proof of infection.

Answer 18

FALSE

-A rising litre would be required.

Question 19

An infection should be treated with an antibiotic with high MIC for the causative organism.

Answer 19

FALSE

Question 20

Neisseria gonorrhoea is an example of a Gram-negative bacillus.

Answer 20

FALSE

-It is a gram negative cocci.

Question 21

Escherichia coli is an example of Gram-negative bacillus.

Answer 21

TRUE

Question 22

Metronidazole is widely used to treat anaerobic infection.

Answer 22

TRUE

Question 23

Amphotericin acts against a wide range of bacteria.

Answer 23

FALSE

Question 24

Blood and Cerebrospinal (CSF) have their own normal bacterial flora.

Answer 24

FALSE

-These are sterile sites.

Question 25

Concerning diagnostic methods: ELISA (also called EIA) tests can be designed to measure antigen or antibody in serum.

Answer 25

TRUE

Question 26

A four fold rise in antigen is required to make a serological diagnosis.

Answer 26

FALSE -Antigen is either present or absent. A four fold rise in antibody titre is usually required for a serological diagnosis the difference between antigen and antibody is basic and important.

Question 27

Diagnosis of malaria is made by visualisation of parasites in a peripheral blood film.

Answer 27

TRUE

Question 28

Bacterial exotoxins are released on cell death.

Answer 28

FALSE | Exotoxins are usually released by the live organism. Endotoxin is released on cell death.

Question 29

Concerning diagnostic methods: a single elevated IgG titre is generally acceptable as serological proof of infection.

Answer 29

FALSE | -A rising litre would be required.

Question 30

Concerning bacterial culture: all clinically important bacteria grow within 48 hours.

Answer 30

FALSE | - There are many slow growing organisms (eg, Mycobacterium tuberculosis can take 4 - 6 weeks to grow).

Question 31

Fluconazole is active against yeasts but not against filamentous fungi such as Aspergillus.

Answer 31

TRUE

Question 32

The complement fixation test measures only IgG antibody in the patients serum.

Answer 32

FALSE -The complement fixation test measures antibody in the patients serum by virtue of its ability to fix complement. Thus it detects a mixture of IgG and IgM and does not distinguish between them.

Question 33

Clostridium tetani is an example of a Gram-positive coccus.

Answer 33

FALSE

Question 34

Concerning diagnostic methods: A single elevated IgM titre is generally acceptable as serological proof of infection.

Answer 34

TRUE | -IgM represents the acute response and therefore suggests current infection.