"We have developed a test chip which can accurately identify 56 virulence genes in the diarrhoea-causing Escherichia coli bacteria and 54 antimicrobial resistance genes covering all the known families of gram-negative bacteria", says Dr Muna Anjum from the UK¡¦s Veterinary Laboratories Agency in Addlestone, Surrey. The chip will speed up the process of diagnosis and treatment by giving quicker results from clinical testing laboratories. The chip will also make it possible to carry out routine surveillance studies to monitor the way genes for virulence and antimicrobial resistance are spread in the environment, food samples, or even in farm and wild animals.

The miniaturised microarray chips were developed by studying and identifying the dangerous genes from samples of gut bacteria including the diarrhoea-causing E. coli bacteria and the food poisoning bug Salmonella. In a test of the new chip screening technique, the most common antibiotic resistance gene was identified in 90% of E. coli and 56% of Salmonella bacteria from a random group of animal and human clinical samples. The tests even identified some unique and previously unknown combinations of virulence genes, whose significance still needs to be determined.

"In the near future, we are planning to automate the method to enable each sample to be tested for up to 600 genes and for 96 samples to be processed in half a day", says Muna Anjum. "This will allow large scale monitoring of bacterial pathogens to see how they gain and lose genes related to disease and its control".

MEDICA.de; Source: Society for General Microbiology