Microbiology

Question 1

What is microbiology?

Answer 1

The study of living organisms of microscopic size including bacteria, fungi, algae, protozoa and viruses.

Question 2

List the microorganisms involved in the following processes;

1. Yogurt & cheese
2. Wine
3. Penicillin
4. Disease
5. Soil food & deterioration

Answer 2

1. Lactobacillus and streptococcus
2. Saccharomyces cerevisiae
3. Penicillin notatum
4. Vibrio cholera
5. Fungus

Question 3

What is pharmaceutical microbiology?

Answer 3

The study of microorganisms associated with the manufacture of pharmaceuticals.

Question 4

List 3 examples where microorganisms are used in the manufacturing process of pharmaceuticals.

Answer 4

• Minimising the number of microorganisms in a process environment.
• Excluding microorganisms & bi-products such as endo and exo-toxins from water.
• Ensuring finished pharmaceutical product is sterile.

Question 5

What are endotoxins and exotoxins?

Answer 5

ENDOtoxins - a toxin inside a bacterial cell that is released from cell wall of gram negative bacteria when it disintegrates.

EXOtoxin - toxin released by living bacterial cell into its surroundings.

Question 6

What is industrial microbiology?

Answer 6

The production of medicinal products such as antibiotics, vaccines, beverages, chemicals, etc. by genetically engineered organisms.

Question 7

What is GMP?

Answer 7

Good Manufacturing Practice ensures products are consistent against quality standards & minimises risks in production that cannot be eliminated in the final product.

Question 8

What is the purpose of GMP?

Answer 8

Minimises human error
Prevent contamination
High quality & consistent production

Question 9

What are the GMP guidelines for a laboratory?

Answer 9

PPE - eg. lab coat, goggles
Environment - air, temperature & humidity
Equipment - cleaned & stored
Validation - stability & conformity

Question 10

List the 5 microbial tests for pharmaceuticals.

Answer 10

1. Microbial limit test (Bioburden test)
2. Sterilisation test
3. Bacterial endotoxin (LAL testing)
4. Growth promotion test
5. Water testing

Question 11

What is involved in water testing?

Answer 11

Different water forms include;
- non-potable/potable
- sterile
- purified
Water is used in;
- solvents
- raw materials
- formulations
Total viable count rules out microbial contamination
Fungal contamination big risk

Question 12

What is involved in the growth promotion test?

Answer 12

Measures the ability of any media to support growth when the inoculum contains a small number of microorganisms. Tests quality.

Question 13

What is involved in LAL testing?

Answer 13

LAL = Limulus Amoebocyte Lysate, is an aqueous extract from Limulus polyphemus (horseshoe crab blood cells) that can detect and quantify endotoxins, which is toxic to humans. LAL reacts with the endotoxins and membrane of bacteria.

Question 14

What is involved in the sterility test?

Answer 14

Tested on products such as eye drops where contamination will result in product not working in desired way.

Question 15

What is the microbial limit test?

Answer 15

Estimates the total number of viable microorganisms & microbial content of a product. This includes the total bacteria count (TBC) and total yeast mould count (TYMC) which is compared against quality standards.

Question 16

What are the 6 ecological sources of contamination for microorganisms? Briefly describe each.

Answer 16

1. Atmosphere - air must be filtered by; filtration, chemical disinfection or UV light @ 240-280nm
2. Water - Quality (raw, softened, de-ionised, distilled) needs to be disinfected by filtration, chemical or UV.
3. Skin & respiratory tract flora - PPE
4. Raw materials - good quality chosen
5. Packaging - protect from moisture & spoilage
6. Equipment - easy to dismantle & clean, smooth surfaces & rounded edges.

Question 17

What is meant by spoilage?

Answer 17

Chemical and physical deterioration of pharmaceuticals through microbial attack to form less potent or inactive forms.

Question 18

Give 2 examples of spoilage.

Answer 18

1. Inadequately preserved olive oil is discoloured, oil-depleted phase, oil globule-rich layer, coalesced oil layer & fungal growth causing bad taste and smell.
2. Tablet stored in humid conditions shows fungal growth of penicillium & sparseness of mycelium & conidiophores.

Question 19

What are chemical disinfectants, antiseptics or preservatives? What are their purpose?

Answer 19

Chemicals that have the ability to destroy or inhibit growth of microorganisms used for a given purpose.

Question 20

What are the 3 things evaluated in a microbial assay?

Answer 20

1. Production - potency, quality control in large scale production - assay high concentration of pure substance.
2. Pharmacokinetics - determination assay with low concentration of pure drug substance in a biological fluid.
3. Antimicrobial chemotherapy - managing, controlling & monitoring assay with low concentration of pure drug in a biological fluid.

Question 21

What are the 2 ways to carry out a microbial assay?

Answer 21

1. Plate diffusion - drug slowly diffused into agar plate with microbial population & gives rise to specific zone of growth inhibition in 1, 2 or 3 dimensions.
2. Rapid reliable reproducible - growth rate over short incubation period either; urease activity (plasma-urea conc.) or luciferase assay (ATP).