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Toxin production by Burkholderia pseudomallei strains and correlation with severity of melioidosis
Abstract:
An exotoxin lethal to cells in culture (cytolethal toxin, CLT) was identified in culture filtrates of Burkholderia pseudomallei, the causative organism of melioidosis. CLT could pass through a 10-kDa cut-off ultrafilter and its properties suggest that it is a peptide. Isolates from soil, animals and man showed differential cytolethality in vitro. The isolates were divided into low, medium and high CLT producers with soil isolates being low producers and isolates from patients with melioidosis encephalitis being high producers. CLT levels are subject to regulation, as a strain isolated from an infected goat was one of the highest producers whereas the same strain isolated from soil was a low producer. In addition to CLT, all isolates produced a protein with cell-elongating activity which was also present in culture filtrates.
Insights
Burkholderia pseudomallei produces a cytolethal toxin (CLT) lethal to cells. CLT production varies by isolate source, with higher levels found in patients with melioidosis encephalitis.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Toxinology
Background:
- Melioidosis is a serious infectious disease caused by Burkholderia pseudomallei.
- Bacterial exotoxins play a crucial role in the pathogenesis of infectious diseases.
- Understanding bacterial toxins is vital for developing effective treatments and preventative strategies.
Purpose of the Study:
- To identify and characterize exotoxins produced by Burkholderia pseudomallei.
- To investigate the differential production of cytolethal toxin (CLT) by various isolates.
- To explore the potential role of CLT in the pathogenesis of melioidosis.
Main Methods:
- Culture filtrates of Burkholderia pseudomallei isolates were analyzed.
- Ultrafiltration was used to assess the molecular weight of the toxin.
- In vitro cytolethality assays were performed on different isolates.
- Cell-elongating activity was also assessed in culture filtrates.
Main Results:
- A cytolethal toxin (CLT), lethal to cells in culture, was identified in B. pseudomallei.
- CLT is a peptide-like molecule, passing through a 10-kDa ultrafilter.
- Isolates showed differential CLT production: soil isolates were low producers, while isolates from melioidosis encephalitis patients were high producers.
- A cell-elongating protein was consistently found in all isolates.
Conclusions:
- Burkholderia pseudomallei produces a potent cytolethal toxin (CLT).
- CLT production is regulated and varies significantly depending on the isolate's source and environment.
- The differential production of CLT may correlate with disease severity in melioidosis.