“
“Background Enteric infections represent a major threat to human health worldwide affecting both children and

adults in developing and industrialized countries. These infections are caused by a number of pathogens including Salmonella, Shigella, Campylobacter species, Aeromonas, Plesiomonas, Vibrio, Yersinia entercolitica, E. coli 0157:H7 and Rotavirus. Among these enteric pathogens, Salmonella enterica with more than 2500 serovars is considered as a key pathogen that can infect a wide range of host species and is the leading cause of acute gastroenteritis. The increased mortality, morbidity and limited availability of specific Barasertib ic50 drugs against these infection demands an alternative to reduce the global disease burden. One such promising alternative is the development of live-attenuated vaccines. These vaccines are attenuated forms of the pathogen itself which can provide defense against the infection from the same pathogen. In case of Salmonella, a facultative intracellular pathogen, specific cell mediated immune response is critical to control and clear the pathogen from the host [1–4]. In order to stimulate cellular immunity with higher efficacy, live attenuated Salmonella are preferred over the inactivated or killed vaccine Ro 61-8048 chemical structure candidates [5–7]. Ideally, a live attenuated vaccine

strain should be able to withstand the host stress, provide defense against the concerned MM-102 solubility dmso pathogen and should successfully colonize the host lymphoid tissues while retaining its avirulent nature. Researchers have Protein kinase N1 established mice models in order to efficiently screen the possible vaccine attributes of genetically modified Salmonella enterica strains or their derivatives [8–12]. However, many live attenuated strains are known to develop systemic infection when administered to immune deficient individuals [13–15]. In order to prevent the systemic infection in immune-compromised patients, it is very crucial to attain sufficient attenuation. Many attenuated Salmonella vaccine strains carrying deletion mutation either in the metabolic gene or in the virulence factors have been developed but with a little success in the clinical

trials [16]. This study primarily focuses on the development of an improved live-attenuated S. Typhimurium strain. A number of S. Typhimurium mutants developed, are known to elicit optimal immune response but showed reduced survival efficacy [17–26]. Earlier studies have shown that only a few such mutants have been actually tested in a pilot study in order to investigate their protection efficacy [27–29]. When tested, such a few proposed vaccine strains resulted in developing diseases in the hosts of variable immune status [20, 30–32]. Therefore, the development of a safer immunogenic live-attenuated S. Typhimurium strain is a need of an hour [33] and can be accomplished by development of a suitably attenuated strain with an avirulent property in immunocompromised individuals.