Efforts to detect and halt the global spread of drug-resistant bacteria are being hindered by a poor understanding of the limitations of crucial laboratory tests. Because infected patients need to be isolated quickly to avoid spreading infections, the failure to identify antibiotic-resistant pathogens is increasing the risk of untreatable outbreaks, microbiologists argue.
This month at the European Congress of Clinical Microbiology and Infectious Diseases in London, Herman Goossens, director of the Laboratory of Medical Microbiology at the Vaccine and Infectious Disease Institute of the University of Antwerp in Belgium, presented data about one type of commercial kit often used to identify particular drug-resistant pathogens1.
The tests contain mixtures of chemicals that encourage some bacteria to grow and discourage others. Samples from stools or rectal swabs are streaked across the growth medium on a plate and then left overnight. The next day, different-coloured growths indicate the presence of different species of resistant bacteria.