jueves, 24 de mayo de 2012

Taking the Pulse of CDC's PulseNet

PulseNet must to develop new pathogen tests that don’t depend on cultures

In December of 2010, 8 people in 3 different states came down with E. coli infections that were eventually linked to hazelnuts from an Oregon distributor. Fifteen years ago these cases most likely would not have been connected, and the outbreak would have gone undiscovered.
But thanks to PulseNet, the government database that tracks DNA information for foodborne pathogens, the pieces of this outbreak puzzle and thousands of others have been put together since the system was launched in 1996.
Of the 10 largest outbreaks in the U.S. in the last decade, 8 would not have been detected had it not been for information stored in PulseNet, according to John Besser, Deputy Chief of CDC's Enteric Diseases Laboratory Branch, who spoke Sunday at the APHL meeting.
The ability to identify a pathogen's unique DNA fingerprint through pulsed-field gel electrophoresis, or PFGE, and to store this data in a central location, has drastically increased the number of outbreaks detected by connecting cases in different states to the same outbreak.
Future Challenges
Though 87 public health laboratories currently contribute specimen data to the system, there is still a backlog of samples waiting to be analyzed that can lead to delays in test results.
Some state labs also receive supplemental funding in the form of CDC's FoodNet and FoodCORE programs. States supported by these programs have been able to boost lab capacity but those lacking this funding remain behind in their ability to process samples as quickly as they come in.
Another challenge faced by PulseNet is the development of new pathogen tests that don't depend on cultures, meaning that they can be done rapidly without isolating and growing bacteria or viruses before analyzing them. While these culture-independent tests can be fast, the results they produce aren't always as accurate as PFGE, and they produce a different characterization of a pathogen from the type recognized by PulseNet.
If PulseNet can evolve to accommodate these new types of information, the process of pathogen identification could potentially be sped up. Another advantage of incorporating results of culture-independent tests is that they could provide better insight into how closely pathogens are related. Whatever happens with culture-independent tests, it must be decided on in a coordinated effort with input from expert’s worldwide.
The reason the German E. coli outbreak linked to sprouts in the spring of 2011 was so devastating was that Germany lacked the coherent pathogen surveillance system that the U.S. has.
Source:  www.foodsafetynews.com
Aporte:  Julia Lissek

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