bacterin

Bacterin is a vaccine preparation made from inactivated (killed) bacteria or their components that is used to induce an immune response against the corresponding bacterial pathogen. Because the organisms are killed, bacterins cannot cause disease but can still stimulate antibody production and cellular responses to target bacterial antigens.

Production: Bacteria are cultured and then inactivated by heat, formaldehyde, phenol, or other chemical methods, and the resulting material is formulated as a suspension. Some bacterins use whole fixed cells (whole-cell bacterins), while others use isolated components such as surface proteins or polysaccharides (subcellular bacterins). Adjuvants are often added to enhance immunogenicity.

Uses: Bacterins have been used in both human and veterinary medicine. Examples include whole-cell vaccines against Bordetella pertussis in older pertussis vaccines and various killed-bacteria vaccines for leptospirosis, salmonellosis, pasteurellosis, and other bacterial diseases in animals. In practice, bacterins provide protection against specific strains included in the vaccine and may require periodic boosters.

Advantages and limitations: They carry a favorable safety profile compared with live vaccines but may be less effective against diverse strains. Proper manufacturing, storage, and adjuvant choice are important to quality and safety.

History: The concept of using killed bacteria to provoke immunity arose with the broader development of inactivated vaccines in the late 19th and early 20th centuries, expanding the vaccine toolbox for infectious diseases.