AUTHOR=Burkhardt Wiebke , Salzinger Carina , Fischer Jennie , Malorny Burkhard , Fischer Matthias , Szabo Istvan 

TITLE=The nematode worm Caenorhabditis elegans as an animal experiment replacement for assessing the virulence of different Salmonella enterica strains

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1188679

DOI=10.3389/fmicb.2023.1188679

ISSN=1664-302X

ABSTRACT=<p><italic>Caenorhabditis</italic> (<italic>C</italic>.) <italic>elegans</italic> has become a popular toxicological and biological test organism in the last two decades. Furthermore, the role of <italic>C. elegans</italic> as an alternative for replacing or reducing animal experiments is continuously discussed and investigated. In the current study, we investigated whether <italic>C. elegans</italic> survival assays can help in determining differences in the virulence of <italic>Salmonella enterica</italic> strains and to what extent <italic>C. elegans</italic> assays could replace animal experiments for this purpose. We focused on three currently discussed examples where we compared the longevity of <italic>C. elegans</italic> when fed (i) with <italic>S</italic>. <italic>enterica</italic> serovar Enteritidis vaccination or wild-type strains, (ii) with lipopolysaccharide (LPS) deficient rough or LPS forming smooth <italic>S</italic>. <italic>enterica</italic> serovar Enteritidis, and (iii) with an <italic>S. enterica</italic> subsp. <italic>diarizonae</italic> strain in the presence or absence of the typical pSASd plasmid encoding a bundle of putative virulence factors. We found that the <italic>C. elegans</italic> survival assay could indicate differences in the longevity of <italic>C. elegans</italic> when fed with the compared strain pairs to a certain extent. Putatively higher virulent <italic>S. enterica</italic> strains reduced the lifespan of <italic>C. elegans</italic> to a greater extent than putatively less virulent strains. The <italic>C. elegans</italic> survival assay is an effective and relatively easy method for classifying the virulence of different bacterial isolates <italic>in vivo</italic>, but it has some limitations. The assay cannot replace animal experiments designed to determine differences in the virulence of <italic>Salmonella enterica</italic> strains. Instead, we recommend using the described method for pre-screening bacterial strains of interest to select the most promising candidates for further animal experiments. The <italic>C. elegans</italic> assay possesses the potential to reduce the number of animal experiments. Further development of the <italic>C. elegans</italic> assay in conjunction with omics technologies, such as transcriptomics, could refine results relating to the estimation of the virulent potential of test organisms.</p>