Oral Presentation Society of Environmental Toxicology and Chemistry Australasia 2021

A rapid and highly sensitive assay for on-site detection of Shiga toxin Escherichia coli in the water (#123)

Alka Rani 1 , Andrew S Ball 1 , Nitin Mantri 2
  1. Centre for Environmental Sustainability and Remediation, School of Science, RMIT University, Bundoora West, Victoria, 3083, Australia
  2. School of Science, The Pangenomics Group, RMIT University, Melbourne, VIC 3083, Australia

Escherichia coli is believed to be a commensal bacterium that benefits mammalian health; however, some mutated strains exhibit pathogenic components which can cause life-threatening diseases. Shiga-toxin Escherichia coli (STEC) strain O157:H7, classified as an enterohemorrhagic E. coli (EHEC) is the most common strain to damage the intestinal wall lining, causing symptoms ranging from bloody diarrhea to severe diseases like thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS). STEC infections estimated to infect over 2.8 million people globally every year. Several outbreaks (approximately 350) of STEC occurred in the USA, Canada, Great Britain, Japan, and Ireland between 1982 and 2006, mainly originated from contaminated water. Contamination of freshly produced agricultural products occurs through contaminated irrigation water. STEC is also associated with recreational activities like swimming, bathing, and spa.

Early and rapid diagnosis of STEC is identified as the most efficacious disease management strategy to reduce morbidity and mortality rates globally. The current standard methods for STEC detection involve sample culturing, the most probable number count (MPN), immunological testing, and polymerase chain reaction (PCR) which are laboratory-based and are expensive, laborious, less sensitive, non-specific, require a skilled person, and lack point-of-care applicability. Additionally, analysis can take up to several days.

To address these issues, a rapid, highly specific, sensitive, and affordable method has been successfully developed for the detection of STEC in water. It is a deployable platform that can fit in anyone’s pocket. The STEC contamination can be found within 20-30 minutes without using any sophisticated lab instruments. The method is fast (< 30 min) that can be done at ambient room temperature and more sensitive than current standard approaches to detect as low as 2 femtograms of DNA. In the poster, we would like to present and talk about this new development.