Pigment array sensor identifies infectious bacteria

Hospitals have used blood cultures as the standard for identifying blood-borne bacterial infections for more than a century. Blood samples are incubated in vials for 24–48 hours, when a carbon dioxide sensor in the vials will signal the presence of bacteria. But after a culture is positive, doctors still need to identify which species and strain of bacteria is in the vial — a process that takes up to another day.

’The major problem with the clinical blood culturing is that it takes too long,’ said Suslick. ’In 72 hours they may have diagnosed the problem, but the patient may already have died of sepsis.’

While there has been some interest in using sophisticated spectroscopy or genetic methods for clinical diagnosis, Suslick’s group focused on identifying bacteria based on the complex mixture of chemicals that they emit as byproducts of their metabolism. Each species of bacteria produces its own unique blend of gases, and even differing strains of the same species will have an aromatic ’fingerprint’.