Defra - Department for Environment, Food and Rural Affairs.

Science Search

Science and Research Projects

Return to Science Search homepage   Return to Project List

Viable but Non-Culturable (VNC) pathogen states and their infectivity potential - CB0442

Description
Biofilms can form on pipe and tank walls associated with mains drinking water supply systems and building water supplies. Previous work has demonstrated how bacterial pathogens can be incorporated into biofilm
structures and survive for extended periods of time. The biofilm itself can create a protective niche for such pathogens, protecting them from mechanical and chemical attack. Earlier work has shown how both non-spore
forming and spore forming species can display high resistance to commonly used disinfectants and how standard methods of detection (primarily culture-based) are ineffective at assessing the viability of these pathogens. When in a stressful environment, bacteria can enter a viable but non-culturable (VBNC) state, where they are unable to grow on highly nutritious or selective media but are still viable and potentially infective. The presence of these VBNC cells has been clearly shown using alternative methods but there is no technique currently available which can accurately measure and quantify the entire viable population. In addition, it is important to be able to show that these VBNC cells retain their infectivity to be able to assess the public health risk they pose.

We propose developing the propidium monoazide/real-time PCR (PMA-PCR) technique for use in detecting and quantifying VBNC bacteria. This is a highly sensitive and specific molecular technique which has been used on different sample types. Preliminary work has indicated that this could be a valuable approach for the rapid, sensitive and specific detection and quantification of VBNC pathogens. To determine the infectivity state of VBNC bacteria, we propose using a nematode model system. Current methods utilise animal models or the use of single-celled amoebae. For numerous reasons, neither of these approaches is favourable. Nematodes are routinely used as model organisms in many research areas and recent work has suggested that they can provide an effective infectivity model. The development of these techniques will aid in the assessment of public health risks which can be posed by such pathogens and the improvement of routine and emergency disinfection and decontamination protocols.
Time-Scale and Cost
From: 2010

To: 2011

Cost: £47,809
Contractor / Funded Organisations
University - Southampton
Keywords
              
Fields of Study
Chemicals and Nanotechnology