Toxin detection

Molecular detection of toxins and other virulence factors associated with Vibrio cholerae

Isolate (pure culture) from urine, stool, blood, environmental, food, other.

Isolate provided on solid culture medium for Vibrio cholerae (slant/stab).

Send as growth on solid culture medium or in appropriate solid transport medium. Culture vessel should be leak-proof or sealed appropriately.

Shipping of specimens shall be done by a TDG certified individual in accordance with TDG regulations. For additional information regarding classification of specimens for the purposes of shipping, consult either Part 2 Appendix 3 of the TDG Regulations or section 3.6.2 of the IATA Dangerous Goods Regulations as applicable.

Gastroenteritis, septicemia, infection, other

Completed Enteric Diseases requisition form.

N/A

Testing is performed, in whole or in part, using a lab-developed test which has not been fully validated/verified due to a lack of well-characterized panel.

In-house developed PCR-based identification of genes encoding:
Toxin:
• ctx (Cholera toxin): causes severe diarrhea; indicative of toxigenic Vibrio spp.\

• vhlyA (Cytolysin): Vibrio cholerae cytolysin (VCC) also called ‘El Tor hemolysin’ is a pore-forming exotoxin which contributes to host cell death particularly of erythrocyte (red blood) cells. VCC is widely thought to enhance virulence of V. cholerae as an accessory toxin with potential capacity to induce increased diarrheal symptoms within hosts infected by ctx-negative strains

• rtx (repeat/accessory toxin): associated with toxin transportation

Whole genome sequencing based methodologies may be applied to aid in toxin or virulence gene confirmation (Not accredited to ISO/IEC 17025 at this time)

7 calendar days. Note: Turnaround times for routine isolates may be extended during major foodborne outbreak activities or due to limited availability of resources.

1. Chow KH, Ng TK, Yuen KY, Yam WC. Detection of RTX toxin gene in Vibrio cholerae by PCR. J Clin Microbiol. 2001 Jul;39(7):2594-7. doi: 10.1128/JCM.39.7.2594-2597.2001. PMID: 11427575; PMCID: PMC88191.
2. Debellis L, Diana A, Arcidiacono D, Fiorotto R, Portincasa P, Altomare DF, Spirlì C, de Bernard M. 2009. The Vibrio cholerae cytolysin promotes chloride secretion from intact human intestinal mucosa. PLoS One 4:e5074.
3. Fields, P.I. et al. 1992. Use of Polymerase Chain Reaction for the Detection of Toxigenic Vibrio cholerae O1 strains from Latin American Cholera Epidemic. J. Clin. Microbiol. Aug: 2118-2121.
4. Saka HA, Bidinost C, Sola C, Carranza P, Collino C, Ortiz S, Echenique JR, Bocco JL. Vibrio cholerae cytolysin is essential for high enterotoxicity and apoptosis induction produced by a cholera toxin gene-negative V. cholerae non-O1, non-O139 strain. Microb Pathog. 2008 Feb;44(2):118-28. doi: 10.1016/j.micpath.2007.08.013. Epub 2007 Aug 31. PMID: 17919878.
5. Sathyamoorthy V, Huntley JS, Hall AC, Hall RH. Biochemical and physiological characteristics of HlyA, a pore-forming cytolysin of Vibrio cholerae serogroup O1. Toxicon. 1997 Apr;35(4):515-27. doi: 10.1016/s0041-0101(96)00163-8. PMID: 9133706.