The Bioburden and Objectionable Organisms

Question 1

What is Bioburden?

Answer 1

• Number and type of microorganisms present in or on a pharmaceutical raw material, medicine or medical device
  
  • Number: Counting methods
  • Type: Absence of objectionable organisms
    
    1. Pathogen: may cause infection
    2. Presence indicate poor quality raw materials/poor manufacture

Question 2

Describe the Characteristics of E. Coli

Where is it found?

Answer 2

• Found in colon of mammals
  
  • Presence might indicate faecal contamination
  • e.g. gelatin used in products, made from animal skin, could be contaminated with faeces
    
    • Test for E. coli & salmonella

Question 3

Describe the Characteristics of Pseudomonas Aeruginosa

Answer 3

• Common contaminant of non-sterile medical products (hospital: food, sinks, taps, mops e.t.c)
• Gram-negative rods, widespread in nature
• Very simple nutritional requirements: grow in distilled water
• Characterised by blue-green puss
• Produces coloured compounds
• Forms biofilms

Question 4

What Coloured Compounds does Pseudomonas Aeruginosa Produce?

Answer 4

• Pyocyanin
  
  • ​Blue, secondary metabolite
  • Cause oxidative stress
  • Virulence factor
• Pyoverdine
  
  • ​Steal iron from host
  • Yellow-green, fluorescent
  • Virulence factor

Question 5

What are biofilms?

Answer 5

• Organised communities attached to surfaces
• 1000x more resistant to drugs than planktonic form
• e.g. dental plaque, catheders

Question 6

What are the Characteristics of Burkholderia Cepacia Complex (BCC)?

Answer 6

• Gram-negative bacteria composed > 18 different species
• Infect immunocompromised people
• Cause ‘swamp foot’ in healthy people
• Forms biofilms
• Produce antinematodal and antimicrobial compounds - used as biocontrol agent
• Highly drug resistant, persist in betadine

Question 7

What are the Characteristics of Candida Albicans?

Answer 7

• Vaginal candida infection
  
  • Normal body flora
  • Can be introduced via sexual contact
  • Cause: prolonged use of antibiotics
  • Also a common cause for UTI
• Oral candidiasis common in:
  
  • Immunocompromised people e.g. AIDs sufferers
  • Babies

Question 8

What are the Factors that can Cause a Microorganism to be Objectionable?

Answer 8

• Cause illness or injury or cause harm with anticipated use of the product
• Affect product stability
• Affect container/closure system
• Affect analytical testing
• Affect active ingredient
• Produce off odours, flavours or undesirable metabolites
• Have potential to grow and exceed total aerobic count specification
• High virulence, low infective dose
• Resistance to antimicrobial therapy

Question 9

What Two Methods are used to test susceptibility to antibiotics?

Answer 9

• Disc diffusion assay
• Broth dilution method

Question 10

Describe the Characteristics of the Disc Diffusion Assay

Answer 10

• Bacteria grown as a lawn on agar
• Discs containing antibiotic placed on plate
• Zone of inhibition (clear) measured

Question 11

Describe the Characteristics of the Broth Dilution Method (Determination of MIC)

Answer 11

• Serial dilutions of antibiotic in medium
• Organism added and grown 18hr
• Measure the lowest concentration of drug able to prevent growth (MIC)