Immunogenicity and protection of a Pasteurella multocida strain with a truncated lipopolysaccharide outer core in ducks

Abstract

Pasteurella multocida infection frequently causes fowl cholera outbreaks, leading to huge economic losses to the poultry industry worldwide. This study developed a novel live attenuated P. multocida vaccine strain for ducks named PMZ2 with deletion of the gatA gene and first four bases of the hptE gene, both of which are required for the synthesis of the lipopolysaccharide (LPS) outer core. PMZ2 produced a truncated LPS phenotype and was highly attenuated in ducks with a > 105-fold higher LD50 than the wild-type strain. PMZ2 colonized the blood and organs, including the spleen, liver and lung, at remarkably reduced levels, and its high dose of oral infection did not cause adverse effects on body temperatures and body weights in ducks. To evaluate the vaccine efficacy of the mutant, ducklings were inoculated orally or intranasally with PMZ2 or PBS twice and subsequently subjected to a lethal challenge. Compared with the PBS control, PMZ2 immunization stimulated significantly elevated serum IgG, bile IgA and tracheal IgA responses, especially after the boost immunization in both the oral and intranasal groups, and the induced serum had significant bactericidal effects against the wild-type strain. Furthermore, the two PMZ2 immunization groups exhibited alleviated tissue lesions and significantly decreased bacterial loads in the blood and organs compared with the PBS group post-challenge. All the ducks in the PMZ2 oral and intranasal groups survived the challenge, while 70% of ducks in the PBS group succumbed to the challenge. Thus, the P. multocida mutant with mutation of the gatA gene and part of the hptE gene proved to be an effective live attenuated vaccine candidate for prevention of fowl cholera in ducks.

Development of Veterinary and Sanitary Measures for the Prevention of Pasteurellosis Infection in Cattle: The Case of the Republic of Kazakhstan

“…The introduction of appropriate vaccines can provide immunity against P. multocida and significantly reduce the risk of infection. Research results show that for effective vaccination, it is necessary to determine the most effective vaccine and develop and follow the vaccination schedule (El-Jakee et al 2020;Mostaan et al 2020;Zhao et al 2022). Currently, in Kazakhstan, vaccines against pasteurellosis have shown mixed results, but none of them provided full protection (Kirkimbaeva et al 2014).…”

A Comprehensive Review on Bacterial Vaccines Combating Antimicrobial Resistance in Poultry

“…Moreover, the use of bacterial vaccines against M. gallisepticum and P. multocida reduced their bacterial loads and improved the immunity in poultry [ 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 ].…”