Isolation, characterization, and application of a novel polyvalent lytic phage STWB21 against typhoidal and nontyphoidal Salmonella spp.

Abstract

Salmonella is one of the common causal agents of bacterial gastroenteritis-related morbidity and mortality among children below 5 years and the elderly populations. Salmonellosis in humans is caused mainly by consuming contaminated food originating from animals. The genus Salmonella has several serovars, and many of them are recently reported to be resistant to multiple drugs. Therefore, isolation of lytic Salmonella bacteriophages in search of bactericidal activity has received importance. In this study, a Salmonella phage STWB21 was isolated from a lake water sample and found to be a novel lytic phage with promising potential against the host bacteria Salmonella typhi. However, some polyvalence was observed in their broad host range. In addition to S. typhi, the phage STWB21 was able to infect S. paratyphi, S. typhimurium, S. enteritidis, and a few other bacterial species such as Sh. flexneri 2a, Sh. flexneri 3a, and ETEC. The newly isolated phage STWB21 belongs to the Siphoviridae family with an icosahedral head and a long flexible non-contractile tail. Phage STWB21 is relatively stable under a wide range of pH (4–11) and temperatures (4°C–50°C) for different Salmonella serovars. The latent period and burst size of phage STWB21 against S. typhi were 25 min and 161 plaque-forming units per cell. Since Salmonella is a foodborne pathogen, the phage STWB21 was applied to treat a 24 h biofilm formed in onion and milk under laboratory conditions. A significant reduction was observed in the bacterial population of S. typhi biofilm in both cases. Phage STWB21 contained a dsDNA of 112,834 bp in length, and the GC content was 40.37%. Also, genomic analysis confirmed the presence of lytic genes and the absence of any lysogeny or toxin genes. Overall, the present study reveals phage STWB21 has a promising ability to be used as a biocontrol agent of Salmonella spp. and proposes its application in food industries.

Controlling the bacterial load of Salmonella Typhi in an experimental mouse model by a lytic Salmonella phage STWB21: a phage therapy approach

“…Our aim was to evaluate the efficacy of phage STWB21 in an animal model that would be advantageous in the future for the treatment of illnesses brought on by the Salmonella Typhi bacterium. In our previous work, we have shown Salmonella phage STWB21 fulfils the initial criteria to be a potential antibacterial agent [25]. In this study, we report that the phage STWB21 can control Salmonella invasion both prophylactically and therapeutically in mice.…”

“…In our previous study, we reported a T5-like phage STWB21, a member of the Siphoviridae family with a dsDNA of length 112,834 bp and a 40.37% GC content [25]. The phage STWB21 against pathogenic S. Typhi was found to successfully eliminate or reduce the bacteria in vitro.…”

Application of a novel lytic Jerseyvirus phage LPSent1 for the biological control of the multidrug-resistant Salmonella Enteritidis in foods

“…In addition, in either treatment, the higher the phage MOIs, the higher the biofilm eradication rate was detected, with an MOI of 50 displaying the highest reduction rates. Many previous studies advocate the efficiency of bacteriophages to eradicate Salmonella biofilms ( Islam et al, 2019 ; Esmael et al, 2021b ; Hosny et al, 2022 ; Mondal et al, 2022 ).…”

Characterization of Salmonella phage of the genus Kayfunavirus isolated from sewage infecting clinical strains of Salmonella enterica

“…10. 3389/fmicb.2024.1391777 Frontiers in Microbiology 08 frontiersin.org identified were found to have a limited range of hosts, however T7-like phages with a wider host range have also been reported (Zhang et al, 2021;Cao et al, 2022;Mondal et al, 2022). Phage vB_SalP_792 was tested for their infectivity against other gram-negative and grampositive clinical pathogens such as E. coli, K. pneumoniae, A. baumannii, P. aeruginosa, Serratia, Citrobacter, Proteus, S. aureus, Streptococcus, and Enterococcus and was recognized as Salmonella specific/Genus specific.…”