The vaccine's attenuation capability has been associated with a deletion in the ery operon that is detected by PCR Sangari et al., 1994, amplifying a 361-bp fragment that distinguishes the B. abortus S19 strain from other B. abortus vaccines and field strains, in which a 1063-bp amplicon has been identified Mukherjee et al., 2005.
La atenuación de esta cepa se ha asociado con una eliminación en el operón ery, que se detecta por PCR Schurig et al., 2002: en la cepa B. abortus S19 se amplifica un fragmento de 361 pb mientras que para otras cepas vacunales y de campo, el amplicón es de 1063 pb Mukherjee et al., 2005.