In vivo screening platform for shiga toxin-producing Escherichia coli (STEC) using Caenorhabditis elegans as a model

Abstract

Shiga toxin-producing Escherichia coli (STEC) strains are the main cause of bacillary dysentery, although STEC strains generally induce milder disease symptoms compared to Shigella species. This study aimed to determine the virulence of STEC using the nematode Caenorhabditis elegans as a model host. Worm killing, fertility and bacterial colonisation assays were performed to examine the potential difference in the virulence of STEC strains compared to that of the control E. coli OP50 strains on which worms were fed. A statistically significant difference in the survival rates of C. elegans was observed in that the STEC strains caused death in 8–10 days and the E. coli OP50 strains caused death in 15 days. STEC strains severely reduced the fertility of the worms. The intestinal load of bacteria in the adult stage nematodes harbouring the E. coli OP50 strains was found to be 3.5 log CFU mL-1. In contrast, the STEC strains E15, E18 and E22 harboured 4.1, 4.2 and 4.7 log CFU ml−1 per nematode, respectively. The heat-killed STEC strains significantly increased the longevity of the worms compared to the non-heated STEC strains. In addition, PCR-based genomic profiling of shiga toxin genes, viz., stx1 and stx2, identified in selected STEC strains revealed that these toxins may be associated with the virulence of the STEC strains. This study demonstrated that C. elegans is an effective model to examine and compare the pathogenicity and virulence variation of STEC strains to that of E. coli OP50 strains.

Caenorhabditis elegans, a Host to Investigate the Probiotic Properties of Beneficial Microorganisms

“…Future opportunities could be to enlarge the panel of pathogens studied. The study of Hwang et al (174) demonstrated that C. elegans is an effective model to examine and compare the pathogenicity and virulence variation of STEC strains (24 strains tested) to that of E. coli OP50 strain. White and Herman (80) demonstrated the merit of a C. elegans approach in the identification of novel genes that are involved in combating the emerging nosocomial bacterial pathogen Stenotrophomonas maltophilia infection.…”

“…Future opportunities could be to enlarge the panel of pathogens studied. The study of Hwang et al ( 174 ) demonstrated that C . elegans is an effective model to examine and compare the pathogenicity and virulence variation of STEC strains (24 strains tested) to that of E .…”

The molecular tug of war between immunity and fertility: Emergence of conserved signaling pathways and regulatory mechanisms

“…Fertility is also reduced upon exposure to Shiga toxin-producing Escherichia coli (SHEC) strains. [60,61] In fact, the dramatic fertility suppression induced by C. neoformans has been used as a rapid screening measure to identify conserved, virulence-determining pathogen genes. [62] Thus, fertility is responsive to immune perturbations and impacts are pathogen specific.…”

Role of Recent Therapeutic Applications and the Infection Strategies of Shiga Toxin-Producing Escherichia coli

“…STEC is one of the six major classifications (pathotypes) of diarrheagenic E. coli . This differentiation depends on medical syndromes, symptoms, epidemiology, the presence of antigen type Stx1 and Stx2 virulence factors, and interaction with epithelial cells ( Hwang et al., 2018 ). Infection with most types of enteropathogenic E. coli causes watery diarrhea ( Figure 1 ).…”

“…Many enteric infections lead to a short-lived dysfunction of the gastrointestinal system. In extreme cases, a severe disorder can occur based on specific pathogenic infections such as that with STEC ( Bron et al., 2017 ; Hwang et al., 2018 ).…”