A microtitration agglutination test for detecting group E streptococcus infection in swine

Area of Science:

• Veterinary Microbiology
• Immunodiagnostics
• Swine Infectious Diseases

Background:

• Streptococcic lymphadenitis in swine is primarily caused by Streptococcus group E type IV.
• Accurate diagnostic methods are crucial for controlling this disease in pig populations.

Purpose of the Study:

• To develop and evaluate a microtitration agglutination test for detecting Streptococcus group E type IV infection in swine.
• To assess the reliability and reproducibility of the developed test in multiple laboratory settings.

Main Methods:

• Development of whole cell agglutinogens from Streptococcus group E type IV.
• Testing agglutinogens against reference and specific antisera, including normal swine sera.
• Evaluation of the microtitration agglutination test in experimentally infected swine and in duplicate serum samples from two laboratories.

Main Results:

• Type-specific agglutinogens of Streptococcus group E type IV showed high specificity, reacting only with homologous antisera.
• Experimentally infected swine developed significant titers (>/=4) two to six weeks post-exposure.
• Two laboratories achieved high agreement (94.1%) in titer readings, with minor discrepancies in test-positive/negative status for 10.2% of samples.

Conclusions:

• The microtitration agglutination test is a reliable and reproducible method for diagnosing Streptococcus group E type IV infection in swine.
• This diagnostic tool can aid in the management and control of streptococcic lymphadenitis in swine herds.