Microbiology

Question 1

What is the advantage of a pus aspirate
over a pus swab?

Answer 1

A swab is more likely to be contaminated with
mucosal commensal flora that will contaminate
the pus aspirate and make it more difficult to
interpret results

Question 2

What are the key safety elements when submitting microbiological or pathological
materials to clinical laboratories?

Answer 2

Needles must be removed from syringes and disposed of correctly

End of syringe must be sealed

Syringe must be labelled

Request form completed

Question 3

What are the key safety elements when submitting microbiological or pathological materials to clinical laboratories?

Answer 3

The packaging shall consist of at least 3 components:
(a) a primary receptacle
(b) a secondary packaging
(c) an outer packaging

Question 4

Provide one clinical example of the utility of a Gram stain of pus from a dental abscess?

Answer 4

Informs empiric choice of antibiotics

Question 5

What us the likely identity of an organism causing infection in dento-alveolar bone?

Answer 5

S.Aureus

Question 6

What antibiotic is used for S.Aureus?

Answer 6

Flucloxacillin

Question 7

What is the most likely identity of an organism found in PA abscess?

Answer 7

Streptococcus Anginosus

Question 8

What AB is used for S.Anginsous?

Answer 8

Pen V

Question 9

What are the atmospheric conditions required to grow pathogens from dental abscess?

Answer 9

Normal atmospheric air only
Normal atmospheric air with extra CO2
Normal atmospheric air with no O2

Question 10

How are pathogens from dental abscesses commonly identified in the hospital
microbiology department?

Answer 10

Agar

API biochemical test

Vitek Biochemical tests

MALDI TOF

Question 11

How are pathogens from dental abscesses susceptibility tested in the hospital
microbiology department?

Answer 11

Disc diffusion

E-test gradient diffusion

Vitek 2 AST

Question 12

What is antimicrobial resistance?

Answer 12

Occurs when microorganisms such as bacteria, viruses, fungi and parasites change in ways that render the medications used to cure the infections they cause ineffective

Question 13

How is antimicrobial resistance determined clinically?

Answer 13

When infection is highly unlikely to respond even to maximum doses of antibiotics

Question 14

What clicnial factors can influence penetration of AB to the site of infection?

Answer 14

Pus

Foreign bodies

Question 15

What us an example of a Black pigmenting anaerobe?

Answer 15

P.Gingivalis

Question 16

What is the most common type of resistance mechanism for beta-lactams in Black pigmenting anaerobes?

Answer 16

Enzymatic inactivation through beta-lactamase?

Question 17

Why is Phenoxymethyl Penicillin now the first line beta- lactam for the management
of dento-alveolar infections?

Answer 17

Equally effective as Amoxicillin but less harmful to resident flora

Question 18

Which of the following micro-organisms from dental infections are usually
susceptible to metronidazole?

Answer 18

Peptostreptococcus micros

Question 19

What are the mechanisms that result in metronidazole resistance?

Answer 19

Enzymatic inactivation

Modified target

Decreased uptake

Increase efflux

Question 20

What antibiotics are part of the 4Cs group?

Answer 20

Co-amoxiclav

Clindamycin

Ceftriaxone

Ciprofloxacin

-> these are associated with Clostridium difficile infection

Question 21

How is antimicrobial stewardship best defined?

Answer 21

Teamwork to minimize antimicrobial resistance
-> coherent actions to promote use of antimicrobials responsibly

Question 22

What are the barriers to collecting pus aspirate in General practice?

Answer 22

Time

Resources (syringes, needles and postal containers)

Finance & clinical competence in obtaining samples