Possible Short Notes

Question 1

Define colonisation

Answer 1

presence of a microorganism on/in a host, with growth and multiplication of the organism, but without interaction between host and organism (no clinical expression, no immune response).

Question 2

Define infection

Answer 2

any illness or condition caused by bacterial growth or toxins

Question 3

Define normal microflora

Answer 3

Normal flora are microorganisms (bacteria, fungi, protozoa, and viruses), mostly bacteria that continuously inhabited the human body

Present in large numbers

Present nearly everywhere other than the lungs

Question 4

Principle and use of latex agglutination kits (staphaurex)

Answer 4

Rapidly identify and differentiate staphylococci which possess coagulase and/or protein A, particularly Staphylococcus aureus

White latex particles are coated with human fibrinogen for detection of clumping factor and specific IgG for detection of protein A.

When mixed on a slide with a suspension of S. aureus, reaction of clumping factor with the fibrinogen and/or protein A with the IgG causes rapid, strong agglutination of the latex particles.

Question 5

Principle and use of latex agglutination kits (pneumo dry spot)

Answer 5

Antibody sensitised blue latex particles dried onto cards covering most of the recognised serological types of pneumococci3,4.

The latex will agglutinate in the presence of sufficient antigen to form visible clumps

Question 6

Lancefield grouping

Answer 6

Lancefield grouping is a serological method for classifying streptococci into one of 20 groups (designated by a letter) based on the presence of polysaccharide and teichoic acid antigens in the bacterial cell wall

These streptococcal group antigens can be extracted from the cells and their presence demonstrated with latex particles previously coated with group-specific antibodies. These latex particles will agglutinate in the presence of homologous antigen, but will remain in smooth suspension in the absence of such

reagents are provided for groups, A, B, C, D, F, and G. The use of a new enzymatic extraction procedure considerably shortens the time required for antigen extraction and much improves the antigen yield, particularly for Group D streptococci.