Wednesday 28 October 2009
Scientists uncover 'family tree' of deadly bacteria
Cronobacter sakazakii attached to neonatal enteral feeding tube
Scientists at Nottingham Trent University and the University of Warwick have traced the genetic lineage of a deadly form of meningitis-causing bacteria that can be found in powdered baby formula. The research, however, has also now revealed a new lineage of the Cronobacter sakazakii bacteria which appears to be found only in clinical or hospital environments, suggesting that there are multiple 'culprits' for incidents of infection amongst newborn babies.
The study has analysed samples of the bacteria dating back to 1951, and collected from every continent in the world. Professor Stephen Forsythe - a specialist in food microbiology from Nottingham Trent University's School of Science and Technology – and Professor Chris Dowson from the University of Warwick, used a DNA typing method known as Multilocus Sequence Typing (MLST). A 'family tree' was then produced, showing the bacteria's various strains and how they relate to different sources.
The results have revealed that there are in fact several lineages or 'stable clones' of the meningitis-causing bacteria. One lineage is primarily associated with powdered infant formula, but another has been found to be present in both infant formula and clinical samples taken from hospitals. Of particular interest, however, is a third strain that is almost uniquely clinical.
The researchers are now extending the database of samples used for DNA typing, whilst their methodology and resultant DNA databases are now available online to act as an international resource for comparisons with other researchers work.
Professor Forsythe said: "Our research has yielded some fascinating results and it's now clear that we have more to learn about the emergence and distribution of this form of bacteria. We will focus our work going forward on the differences between the virulence of each of the genetic lineages that we've identified."
He added: "By understanding the lineages of the meningitis-causing bacteria and their sources, it is hoped the research will help to minimise incidents of infection amongst newborn babies. Further data may also lead to processes for better identification of the actual source of infection for newborn babies."
The findings have been published in the online journal BMC Microbiology.
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View the research paper published in BMC .
The researchers methodology and resultant DNA databases are now available online to act as an international resource for comparisons with other researchers work – visit the Cronobacter MLST website for more information.
Professor Stephen Forsythe
Professor Forsythe's main areas of research are in food borne and clinically important pathogens. This spans from food hygiene in factories (including HACCP implementation and microbial risk assessment) through to detection methods (ATP bioluminescence, enrichment broth and chromogenic agar), molecular characterisation (pulsed-field gel electrophoresis and PCR probes) and virulence (using mammalian tissue culture).
Nottingham: The Science City
Nottingham was designated as a Science City in 2005 in recognition of its rich scientific heritage, industrial base and role as a leading research centre. Nottingham has since embarked on a wide range of business, property, knowledge transfer and educational initiatives (Nottingham Science City website) in order to build on its growing reputation as an international centre of scientific excellence. Nottingham Trent University is a partner in Nottingham: the Science City, with Vice-Chancellor Professor Neil Gorman chairing the board.
