A pathogen that colonises work surfaces and dishcloths, arms itself against gradual drying out by growing into an unusually large, ribbon-like organism, Wageningen microbiologists have discovered. In addition, the bacteria is becoming resistant to disinfectants such as bleach.
Under the microscope it looks as though the rod-shaped bacteria gets bigger as it dries up, but this is not the case. Instead, it loses the ability to divide. New cells are made, but they do not split off. ‘This is called filamentation,’ explains Beumer. ‘In the lab it’s possible to grow salmonellas with fifty to a hundred cell nuclei. We don’t know why this happens. If the bacteria gets enough water, though, the new organisms do split off.’
The monster-salmonellas are resistant to bleach and once they have formed, they are more difficult to get rid of – useful information for the food industry and for households. Beumer’s group is now examining how effective filamentous bacteria are at infecting human gut cells. The research has been published in the Journal of Food Protection.