It's a deep explanation about the principles of agglutination specifically bacterial agglutination.

1. Bacterial Agglutination
Author: Multiple Authors
Citation: Multiple Authors. 2011. Bacterial agglutination.
Publication Date: November 2011

2. Serogrouping of Shigella sonnei
Serogrouping of a Shigella sonnei isolated from a patient stool sample. Results indicate agglutination in group D
antisera. (Rebecca Buxton, University of Utah, Salt Lake City, UT)
American Society For Microbiology ©

3. Serogrouping of a Salmonella Species
Serogrouping of a Salmonella species isolated from a patient stool sample. Results indicate agglutination in polyvalent and
group B antisera. (Rebecca Buxton, University of Utah, Salt Lake City, UT)
American Society For Microbiology ©

4. American Society For Microbiology ©
Lancefield Grouping for Streptococcus Showing Agglutination
Lancefield grouping for Streptococcus showing agglutination. Agglutination is occurring in only one of the six combinations of antigen-
antibody used in this test. An unknown species of Streptococcus was subjected to analysis with the Lancefield grouping test, a
commercially available latex agglutination immunological assay that detects carbohydrate in the cell wall of streptococci. A standard
amount of enzyme-extracted Streptococcus was applied to each of the six rings on the plastic card. A different solution of latex beads
coated with a specific Lancefield group antibody was then put into each of the six wells, where presumably only one antibody would
recognize the carbohydrate antigen of the unknown Streptococcus. Agglutination occurs when the latex beads coated with antibody
specifically bind to the antigen in the ring and crosslinks of multiple latex beads result. Visible agglutination or clumping of the latex
beads only occurred in well 4, which corresponds to Lancefield group D and thus identifies the unknown species as one of the group D
Streptococcus. Agglutination tests are widely used for identifying many different pathogens and are quick, sensitive, and specific.
(Janelle Hare, Morehead State University, Morehead, KY)

5. American Society For Microbiology ©
Lancefield Grouping for Streptococcus Showing Agglutination (Labeled view)
Lancefield grouping for Streptococcus showing agglutination. Agglutination is occurring in only one of the six combinations
of antigen-antibody used in this test. An unknown species of Streptococcus was subjected to analysis with the Lancefield
grouping test, a commercially available latex agglutination immunological assay that detects carbohydrate in the cell wall of
streptococci. A standard amount of enzyme-extracted Streptococcus was applied to each of the six rings on the plastic card.
A different solution of latex beads coated with a specific Lancefield group antibody was then put into each of the six wells,
where presumably only one antibody would recognize the carbohydrate antigen of the unknown Streptococcus.
Agglutination occurs when the latex beads coated with antibody specifically bind to the antigen in the ring and crosslinks of
multiple latex beads result. Visible agglutination or clumping of the latex beads only occurred in well 4, which corresponds to
Lancefield group D and thus identifies the unknown species as one of the group D Streptococcus. Agglutination tests are
widely used for identifying many different pathogens and are quick, sensitive, and specific.
(Labeled view) (Janelle Hare, Morehead State University, Morehead, KY)

6. American Society For Microbiology ©
Effect of Different Ratios of Antibody and Antigen on Agglutination
An illustration of the effect of antibody and antigen concentrations on the amount of antibody-antigen precipitate observed
in an agglutination reaction. Precipitation occurs when the concentrations of antibody and antigen allow the formation of
crosslinked networks, created when antibodies bind two or more antigen epitopes. Maximal precipitate is observed in the
concentration range termed "zone of equivalence." In the prozone region, the concentration of antibody exceeds the
concentration of antigen and little antibody-antigen precipitation will be formed. In the postzone region, the concentration of
antigen exceeds the concentration of antibody, again, limiting the production of antibody-antigen precipitate. (D. Sue Katz,
Rogers State University, Claremore, OK)

7. Positive and Negative Agglutination
Positive and negative agglutination.
(A) Positive agglutination of Salmonella by anti-Salmonella antibodies.
(B) No agglutination is observed when anti-Salmonella antibodies are mixed with Escherichia coli. (Anne Hanson, University
of Maine, Orono, ME)
American Society For Microbiology ©

8. Agglutination Test
Agglutination test. The color-enhanced latex slide test (Fisher) was used for the detection of the protein–A associated with
Staphylococcus aureus.
(A) Staphylococcus aureus showing a positive agglutination reaction indicated by red clumps and a change of background
color from purple to blue.
(B) Staphylococcus epidermidis showing a negative agglutination reaction with no clumping and no color change. Tests were
prefomed on cultures incubated on tryptic soy agar for 24 hours at 37oC. (Tasha Sturm, Cabrillo College, Aptos, CA)
American Society For Microbiology ©

9. Streptococcal Latex Agglutination Assay Testing
Streptococcal latex agglutination assay testing. The assay shows agglutination indicating a positive reaction for group A
Streptococcus (left) and no agglutination indicating a negative reaction for group B Streptococcus (right). (Ken Van Horn,
Focus Diagnostics, Inc., Cypress, CA)
American Society For Microbiology ©

10. Agglutination Assay in Tube
Tube agglutination assay. An unknown organism shows agglutination in the left tube and no agglutination in the right tube.
(Ken Van Horn, Focus Diagnostics, Inc., Cypress, CA)
American Society For Microbiology ©

11. Streptex Latex Agglutination Assay
Streptex (Remel) latex agglutination assay for typing of beta-hemolytic streptococci. The assay shows agglutination indicating
a positive reaction for group F streptococci. (Ken Van Horn, Focus Diagnostics, Inc., Cypress, CA)
American Society For Microbiology ©