London, July 28 - Researchers have developed a technique to capture live images of how bacteria infect their host.

While most studies of bacterial infection are done after the death of the infected organism, this system developed by scientists at the Universities of Bath and Exeter is the first to follow the progress of infection in real-time with living organisms.

Researchers used developing fruit fly embryos as a model organism, injecting fluorescently tagged bacteria into the embryos and observing their interaction with the insect's immune system using time-lapse confocal microscopy.

Confocal microscopy is an optical imaging technique used to increase micrograph contrast and/or to reconstruct 3-D images. A micrograph is a photograph or similar image taken through a microscope.

The researchers can also tag individual bacterial proteins to follow their movement and determine their specific roles in the infection process.

'Cells often behave very differently once they have been taken out of their natural environment and cultured in a petri dish,' explained Will Wood, research fellow in biology and biochemistry at Bath University.