Sereny test

Sereny test is a microbiological test used to determine the virulence of certain bacteria, specifically those belonging to the genus Escherichia coli (E. coli) and Shigella. This test is named after the Hungarian physician Béla Serény, who developed it in the 1950s to identify strains of bacteria capable of causing conjunctivitis in humans, a condition often referred to as "pink eye". The Sereny test is particularly significant in the study of enterobacteria that are capable of invading epithelial cells and causing gastroenteritis and other invasive diseases.

Procedure

The Sereny test involves the inoculation of a live animal, typically a guinea pig, with a bacterial culture. The bacteria are applied directly to the conjunctival sac of the guinea pig's eye. After a period of 24 to 48 hours, the animal is observed for signs of eye infection, such as redness, swelling, and the production of pus. A positive Sereny test, indicated by the development of conjunctivitis in the guinea pig, suggests that the bacterial strain being tested possesses virulence factors enabling it to invade epithelial cells and cause disease.

Applications

The Sereny test has been primarily used in research settings to study the pathogenic mechanisms of E. coli and Shigella strains. It helps in distinguishing between invasive and non-invasive strains of these bacteria, which is crucial for understanding their disease-causing potential and for developing appropriate treatments and preventive measures. Although the use of the Sereny test has declined with the advent of molecular biology techniques that allow for the identification of virulence genes directly, it remains a valuable tool in certain contexts where such technologies are not available or when a phenotypic confirmation of virulence is required.

Ethical Considerations

The use of live animals in the Sereny test raises ethical concerns regarding animal welfare. As with any research involving animals, it is essential that the principles of the Three Rs (3Rs) (Replacement, Reduction, and Refinement) are applied to minimize animal use and suffering. Alternatives to the Sereny test, such as in vitro assays and molecular techniques, are increasingly being developed and utilized to reduce the reliance on animal models in microbiological testing.

See Also

• Microbiological culture
• Virulence
• Conjunctivitis
• Gastroenteritis
• Escherichia coli
• Shigella