Microbiology

Question 1

What is the general media for bacteria

Answer 1

TSA (Trypticase soy agar)

TSA is a growth media for the culturing of moderately to non fastidious bacteria. It is a general-purpose, non-selective media providing enough nutrients to allow for a wide variety of microorganisms to grow.

Question 2

What is the media for yeasts and moulds

Answer 2

SDA (Sabouraud Dextrose Agar)

SDA is a selective medium primarily used for skin yeasts and moulds. The acidic pH of this medium (pH about 5.0) inhibits the growth of bacteria but permits the growth of yeasts and most filamentous fungi.

Question 3

What is the media for water bacteria?

Answer 3

R2A (Reasoner’s 2A agar)

R2A agar is a culture medium[1] developed to study bacteria which normally inhabit potable water.[2] These bacteria tend to be slow-growing species and would quickly be suppressed by faster-growing species on a richer culture medium

Question 4

What is the media for E. coli?

Answer 4

MacConkey

Question 5

What is the media for P. aeruginosa

Answer 5

Cetrimide

Question 6

What are the media for sterility test

Answer 6

Fluid Thioglycollate Medium (FTM) and
Soyabean Casein Digest Medium (SCDM).

Question 7

What is FTM used for and at what temp incubated?

Answer 7

anaerobic and aerobic bacteria - store at 30-35 °C

Question 8

What is SCDM used for and at what temp incubated?

Answer 8

fungi and aerobic– store at 20-25 °C

Question 9

What is the sample size used for a sterility test?

Answer 9

Number of samples changes dependent on batch size and product type.
For normal parenteral batches >500 then 20 containers or 2% whichever is less

Question 10

What are the two methods available for sterility test?

Answer 10

Test methods = Membrane Filtration Method and Direct Inoculation

Question 11

What do you need to do when developing the sterility test for a product

Answer 11

Need to demonstrate no anti-microbial action of the product on the sterility test. Inoculate with less than 100cfu, do the test and leave for 14 days to see turbidity.

Question 12

What do you need to do to each batch of medium for sterility test

Answer 12

1) Demonstrate it’s sterile
2) Demonstrate it grows bacteria and yeast and moulds
3) Staph, Bacillus, pseudomonus, Clostridium sporogenes (anaerobic), candida and aspergillus

Question 14

What are used to positively show sterility media grows bugs?

Answer 14

Staphylococcus , Bacillus, pseudomonus, Clostridium sporogenes (anaerobic), candica and aspergillus

SBACC

Question 15

What are methods to sanitise a purified water system?

Answer 15

Ozone
Heat
Chemical – peracetic acid and hydrogen peroxide

Question 16

How would you PQ a purified water system?

Answer 16

3 stage approach –
1 – system not in use
2 – system in use at risk
3 – system in full use

Question 17

What’s involved in stage 1 ‘system not in use’ when PQ-ing PW system?

Answer 17

• All user points and return sampled every day for 4-6 weeks.
• Sampling regime should include monitoring of feed water source, between each of the pre-treatment stages, pre- and post RO membrane, post final purification stage and storage tank
• Samples analysed for TOC, conductivity, endotoxin and micro
• Results obtained should establish alert and action levels for phase 2

Question 18

What’s involved in stage 2 ‘system in use at risk’ when PQ-ing PW system?

Answer 18

• Elevated testing should be performed including monitoring of generation system, storage vessels, user points and any concern points identified at phase 1
• Should also monitor before and after micro reduction systems like UV lamps
• Samples should be taken as intended by production
• Samples analysed for TOC, conductivity, endotoxin and micro
• SOPs finalised

Interim report issued to say can be used for routine production

Question 19

What’s involved in stage ‘ system in full use’ when PQ-ing PW system?

Answer 19

• Intended to say system ok over long usage, typical 12 months to allow for seasonal variation
• All user points monitored on a pre-defined schedule
• Trends monitored
  VSR issued

Question 20

What are organisms used for showing growth media is OK

Answer 20

Staphylococcus aureus,
Pseudomonas aeruginosa,
Bacillus subtilis,
Candida albicans,
Aspergillus

Use in the appropriate media

Question 21

Examples of GPCs?

Answer 21

Staphylococcus aureus
streptococcus

Question 22

Examples of GPRs?

Answer 22

Bacillus subtilis
Clostridia Spore formers
Geobacillus stearothermophilus

Question 23

Examples of GNRs?

Answer 23

Pseudomonas aeruginosa
E.Coli,
Salmonella
Campilobacter

Question 24

Examples of GNCs?

Answer 24

Neisseria gonorrhoeae,
Neisseria meningitidis

Question 25

What is the specification for PW?

Answer 25

100 cfu / ml
<0.25 eu/ml endotoxin (dialysis)
0.2 ppm nitrates
500 ppb TOC
<4.3 μS/cm @ 20°C
0.1ppm heavy metal (don’t need test if conductivity <1.1 μS/cm @ 20°C)
10 ppb Al (dialysis)

Question 26

What is the specification for WFI?

Answer 26

10 cfu / ml
<0.25 eu/ml (dialysis)
0.2 ppm nitrates
500 ppb TOC
<1.1 μS/cm @ 20°C
0.1ppm heavy metal
10 ppb Al (dialysis)

Question 27

What are some common pharmaceutical preservatives?

Answer 27

Benzalkonium Chloride – nasal sprays / eye drops / topicals

Parabens – creams, ointments, lotions – good against bacteria and moulds

Benzyl Alcohol – injectables and topical formulations

Sorbic Acid and its salts – effective against fungi

Thimerosal – mercury containing compound used in some vaccines and ophthalmic formulations.

Question 28

What is the test to demonstrate that media grows bugs called?

Answer 28

Growth promotion test
Or
Fertility Test

Question 29

Why is Bacillus used for sterility testing?

Answer 29

It is both aerobic and anaerobic (aerobic by preference)

Question 30

Why does the anti-microbial action test use <100 CFU

Answer 30

Otherwise the sample would be overdiluted with the growth medium from the inoculation sample. The bacteria would grow in that, reducing the sensitivity of the test and therefore giving false positives.

This is called carryover

Question 31

How long is the Growth promotion test for FTM and SDCM incubated for and how long is a sterility test incubated for

Answer 31

FTM = 3 days
SDCM = 5 days
Sterility test = 14 days

Question 32

When would you use a direct inoculation method for a sterility test?

Answer 32

When you can’t do it by membrane filtration e.g. creams or some suspensions (Cabo like paint and needs to grow, sample, grow sample, sample, grow sample until there’s sufficient clarity to see turbidity from bacteria if growth present)

Question 33

How do you prepare catgut and sutures for sterility test?

Answer 33

3 strands approx. 30 cm long