Customised pathogen arrays for diagnosing
multiple infections simultaneously
The Bacterial Microarray Group at St George’s (BµG@S), University of London, has been working with OGT to develop microarrays with whole-genome coverage of a variety of pathogenic organisms, such as C. difficile, C. jejuni, M. tuberculosis, H. influenzae and others. BµGS was established in 2000 as a Wellcome Trust funded multi-collaborative facility that provides DNA microarray technology to approximately 100 groups from the microbial pathogen research community throughout the UK.
“We have a very well established partnership with OGT and we have recently arranged for all of our custom pathogen microarrays to be manufactured by them,” said Philip Butcher, Professor in Medical Microbiology at St George’s and a principal investigator within BµGS. “We realised that for BµGS to survive as a community resource, our microarrays must stay up to date. OGT’s ink jet in situ synthesis technology is hugely powerful, making it easy to design or modify arrays really quickly. In the past, it took months to make a pathogen array, but now OGT can manufacture a microarray for us within a week of a new pathogen genome sequence being released! This enables us to make immediate use of any new genome sequence information being released so as to keep the gene content of the arrays up to date very easily. This is an important feature for the research community. The printing technology allows densities of up to 244,000 spots per slide, allowing for multiple probes per gene, covering all intergenic regions of a genome and covering both strands of DNA. These high density arrays provide more precise dissection of genetic diversity in comparative genomic hybridisation experiments, allow detailed analysis of transcriptional activity of a genome and permits ChIP-on-chip experiments to look at DNA binding proteins. It also means we can have multiple copies of genomes on each slide, which is highly cost-effective.”
OGT and BµGS are currently developing a diagnostic microarray for simultaneously detecting a range of known pathogens that indicate the presence of sexually transmitted infections, from just one patient sample. “The pan-pathogen array will be particularly useful in genito-urinary medicine because many patients may have multiple infections, such as gonorrhoea, Chlamydia and Herpes simplex. Certain syndromes associated with STIs may have multi-pathogen aetiologies. Not all of these may be tested for by conventional microbiology screening,” Philip explained. “Having a test that can identify all of these simultaneously would be hugely beneficial to clinicians because they could offer appropriate treatment to cover all of the infections at once.”
“Our relationship with OGT has been very successful,” continued Philip. “We have worked closely with a number of people there and found their scientific expertise to be excellent. Our collaboration is very much a two-way partnership, as OGT sends bacterial array queries to us and, equally, we direct groups to OGT’s technology. I hope that OGT and BµGS will remain in partnership for many more years so that academics in the pathogen community can make the best use of the current and emerging OGT microarray technologies.”