Assessment of novel live attenuated Salmonella Enteritidis mutants ΔaceE, ΔasmA and ΔaceE/ΔasmA as vaccine candidates.

Abstract

Salmonella enterica serovar Enteritidis is a non-typhoidal strain of Salmonella bacteria which was responsible for numerous Salmonellosis epidemics in recent years. It usually infects humans indirectly via the consumption of infected food products including poultry and eggs. In this project, we aim to create a live attenuated Salmonella Enteritidis mutant by knocking out an ATP synthesis-related gene, aceE, from the wild-type genome using the Lambda Red recombinase system. This ΔaceE mutant, along with two other mutants created previously in other projects namely ΔasmA mutant and ΔaceE/ΔasmA double mutant, were screened through a battery of in vitro and in vivo tests to investigate their use as possible vaccines against Salmonellosis. We found out that the mutants had retarded growth rates, were less invasive, and elicited weaker antibody response in the host system, as compared to the wild-type strain.