But some bacterial diseases such as pneumonia are difficult to cure, even with antibiotics; and when a medical device such as a catheter is inserted in the body, it often gets infected with bacteria that cause many problems for the patient. In these cases, the bacteria are not acting as independent cells, but are all stuck together by gluey substances that they secrete, in unison.
Many, many cells of this infection will then form a slimy or sticky colony which is called a biofilm. The gluey slime acts as a barrier to stop antibiotics getting to the cells, and sticks the colony firmly to any surface (such as the lining of the lungs, or the plastic medical insert).
There is also a problem that many of the infections caused by these biofilms are resistant to common antibiotics, even if the slimy mass can be disrupted.
Biofilms of micro-organisms are also widespread in natural and industrial situations.
Every day food items
Bacteria in biofilms talk to each other
In a previous article, I wrote of the amazing ability of trees to communicate with each other (and with other beneficial organisms) using volatile chemicals and soluble chemicals travelling through the soil. (au.christiantoday.com)
Similarly, individual bacterial cells in a slimy biofilm can send chemicals to communicate with each other – and in this way they co-ordinate some of their behaviour such as moving to spread the film in an organised way, and producing chemicals to kill other bacteria in the neighborhood. The slime acts like a colony. (www.learner.org)
Scientists already knew that individual cells inside an animal communicate by using chemical and electrical stimulations. When an embryo is growing to be a baby, or when every tissue in your adult body is regenerated as old cells die and new ones form, there is a sophisticated communication network going on between the newly formed cells to make sure the right thing happens. The finding that living bacterial cells communicate in similar ways was expected.
The bacteria use 'roadways' of extra DNA to guide them as the film grows
Australian researchers at the University of Technology, Sydney have found that there are also physical properties of a biofilm that enable the bacteria to co-ordinate the way they grow. By using several different types of high-resolution microscopes, in real time, enhanced by computer graphics, they could literally watch the cells moving as the biofilm expanded.
First, they found that little railway tracks, or furrows, formed in the slimy biofilm and helped the bacteria line up as they multiplied, ready to all move off in the one direction. Next, they noted that DNA excreted to the outside of the cell acted like a long rope, to guide the growing line of bacterial cells and keep the expansion of the slime co-ordinated. It also acted as one type of glue to keep the cells stuck in the film. (This DNA is different from the molecules inside the cell that contain the genetic information.) (www.abc.net.au)
In any shop
Some new ways to get rid of the slimy mass
Many chemical tricks have been tried over the years to dissolve part of the slime and allow antibiotics in. Some are partly successful. Tea-tree oil, for example, is a powerful solvent (have you ever tried to keep it in a plastic container? Don't – it dissolves the plastic and leaks out). It can be used to clean catheters and other devices, to stop the biofilms forming. But it eventually gets washed away and it can be irritating to bodily tissues.
A very recent article has described a new urinary catheter design that physically disrupts the biofilm and stops it sticking to the surface. The interior of the researchers' new catheter has a thin rubber film that stretches when fluid moves through the inside of the tube, like a rubber band stretching and relaxing. This just 'pops' the biofilms right off the surface, and the running fluid washes them away. (www.sciencedaily.com)
So far, they have only built a prototype using – wait for it – a 3-D printer, but they have shown proof of principle. If it works, and it seems it will, then the same type of mechanics can be used in other places where biofilms are a problem – such as the bottoms of boats, air conditioning ducts, milk processing (and many other examples).
In the meantime, until scientists find better ways of controlling biofilms, hygiene is the most effective way to keep safe. Those who need to deal with any medical inserts should follow the advice of their medical practitioners. Usually this means adhering to strict handwashing and hand-DRYING before touching the insert, and using any antiseptic or antibiotic that is recommended.
There are many places in the Bible where cleanliness is decreed, and it helped the ancients reduce the spread of disease. Some verses are practical as well as metaphorical, for example, Psalm 51:7 "Purge me with hyssop, (an antiseptic and medication for coughs and tummy ache) and I shall be clean; wash me, and I shall be whiter than snow."
Dr Mark Tronson is a Baptist minister (retired) who served as the Australian cricket team chaplain for 17 years (2000 ret) and established Life After Cricket in 2001. He was recognised by the Olympic Ministry Medal in 2009 presented by Carl Lewis Olympian of the Century. He mentors young writers and has written 24 books, and enjoys writing. He is married to Delma, with four adult children and grand-children.
Mark Tronson's archive of articles can be viewed at www.pressserviceinternational.org/mark-tronson.html