Rights: The University of Waikato Published 18 June 2008 Download

ESR scientist Dr Brent Gilpin is involved with PulseNet – a system of monitoring disease outbreaks in the world. PulseNet uses pulsed field gel electrophoresis to identify individual strains of bacteria, which can help identify the source of the outbreak and can be used to limit the spread of the disease.


PulseNet is an organisation that was set up in the United States following an outbreak of food-borne disease at a burger restaurant. There was a burger chain in the US that had contaminated their meat that they use for cooking burgers and, unfortunately, they cooked that meat neither long enough nor hot enough to actually kill the bacteria in the middle. So when people ate their hamburgers, they were also eating E. coli O157. As a result, there was at least 700 people became ill, a number of people died, and a number of people who required liver transplants and other fairly serious consequences. To actually identify this outbreak – because it was across a number of states – they used a technique called PulseNet gel electrophoresis. The trouble is, is that there is often lots of outbreaks going on at once, so to find out whether a number of cases are actually linked together, you use a DNA fingerprinting technique to say that these patients have the same organisms infecting them, the genetic profile of that organism is indistinguishable, therefore there may be a common source, whereas some other people infected from different sources may have a completely different genetic profile of the organism that caused their illness. So the key to PulseNet has been getting people to use the same methodology to produce these DNA fingerprints, and then to have electronic databases which are able to compare the fingerprints robustly and reliably, not just within one lab, but between different labs, between different countries and in real time, so that a pattern can be sent to us from somewhere in the US, or in Hong Kong, and we can compare it with icelets we have, and say that we have something very similar, in which case, it may be something that has been internationally spread, or that we don't have anything very similar at all. So there has been an expansion of this network beyond the US, throughout the whole world, and there is now PulseNet networks worldwide using the same methodology, the same standardised methodology to analyse bacteria.