CEA-Leti’s experts have collaborated with a team of French and Swiss scientists to demonstrate a lens less imaging technique that could easily be implemented in cost-effective and compact devices in phage laboratories to accelerate phage therapy diagnosis.
The growing number of drug-resistant bacterial infections worldwide is driving renewed interest in phage therapy. The WHO has warned of “a slow tsunami” of antibiotic resistance that by 2050 could result in 10 million annual deaths from antibiotic-resistant infections.
“We report bacterial susceptibility to anti-Staphylococcus aureus phage in three hours and estimation of infectious titer in eight hours and 20 minutes,” the paper explains. “These are much shorter time-to-results than the 12-to-24 hours traditionally needed, since naked eye observation and counting of phage plaques is still the most widely used technique for susceptibility testing before phage therapy. Moreover, the continuous monitoring of the samples enables the study of plaque-growth kinetics, which enables a deeper understanding of the interaction between phage and bacteria.”
“This shows that our prototype is also a suitable device to track phage resistance,” said Pierre Marcoux, a scientist in CEA-Leti’s Department of Microtechnologies for Biology and Health. “Lensless imaging is, therefore, an all-in-one method that could easily be implemented in cost-effective and compact devices in phage laboratories to help with phage-therapy diagnosis.”
In a recent research article, “Phage Susceptibility Testing and Infectious Titer Determination Through Wide-Field Lensless Monitoring of Phage Plaque Growth”, the team reported a lensless technique for testing the susceptibility of the bacterium to the phage on agar and measuring infectious titer, among other results.
In addition to CEA-Leti, the team included a Grenoble consortium of researchers from CEA-Interdisciplinary Research Institute of Grenoble (CEA-Irig), the French National Centre for Scientific Research-Laboratoire des Technologies de la Microélectronique (CNRS-LTM), and the phage-therapy team from Lausanne University Hospital in Switzerland, better known as CHUV in French.
In addition to investigating computer-assisted methods to ease and accelerate diagnosis in phage therapy, the team studied phage plaque using a custom-designed, wide-field lensless imaging device, which allows continuous monitoring over a very large-area sensor (8.64 cm2).