Getting out of a sticky situation

Biofilms get a pretty bad rep, and rightly so. Colloquially known as ‘slime’, these sticky scaffolds of polysaccharides, proteins and DNA are produced by colonies of bacteria and let them cling to wet surfaces, whether those are crustacean shells, water pipes or artificial cardiac valves.

Bacteria within biofilms are difficult to kill, which makes them a real problem in hospitals. The bacterial colonies are often more resistant to antibiotics than their free-living relatives, perhaps because the biofilm cocoons the bacteria in the centre and prevents drugs from reaching them. Biofilms are also tricky to remove by cleaning and are impervious to many detergents. Once they’re there, you’re kind of stuck with them, if you’ll excuse the pun.

But what if we could harness the adhesive power of biofilms for good? Could we use them to deliver useful molecules or drugs? A group of researchers is working on that very problem, right now.

Cholera loves chitin

The Broad Street pump

Last year, I was lucky enough to visit the Wellcome Collection’s Dirt exhibition, which featured several microbiology treasures. Among other objects, I saw an original van Leeuwenhoek microscope and a first edition of Robert Hooke’s Micrografia. I also had the chance to get close to an original copy of John Snow’s cholera map.

Snow, who is commonly considered to be the father of modern epidemiology, is most famous for identifying where cases of cholera were occurring during an epidemic in London in 1854. This allowed him to trace the source of the outbreak – a contaminated water pump on Broad Street.

Today, very few cases of cholera are reported in the UK; however, it is endemic in many other countries and resulted in more than 100 000 deaths in 2010. It is caused by the bacterium Vibrio cholerae, which produces toxins in the small intestine of an infected person, causing them – if untreated – to produce more than ten litres of diarrhoea a day. Death comes as a result of dehydration.

As shown by Snow in 1854, people get the disease through drinking contaminated water. This is a real problem in much of the world, where clean drinking water is not accessible for local populations.