Where do antibiotic resistant microbes come from?

The increasing threat from antibiotic resistant microbes is sufficient to cast the world back into the dark-ages of medicine according to Prime Minister David Cameron, speaking at the launch of an inquiry last year.

It is estimated that microbial strains that are resistant to drugs are responsible for 5,000 deaths a year in the UK and as many as 25,000 in Europe.

One academic from Bangor University is contributing to the battle against antibiotic resistance, and is researching on several ‘fronts’, including developing a quick and efficient test that would identify bacterial strains that carry antibiotic resistant genes.

Merfyn Williams and his team at the School of Medical Sciences are researching the differences within the DNA of families of bacteria, which enable some of those bacteria to exhibit resistance to antibiotics. Many bacteria are not naturally antibiotic resistant in the environment which surrounds us, rather, some bacteria have undergone an evolutionary change in their DNA which gives them the potential to withstand antibiotics.

“The easiest way to describe what happens some bacteria that carry genes that enable them to be potentially resistant to some antibiotics is to describe them as having a ‘switch’ which is turned on when they are stressed or come into contact with antibiotics, and it is only at that point that they exhibit antibiotic resistance,” explains Merfyn Williams.

These strains which have the potential to resist antibiotics are around us in the environment and inside us possibly as part of our normal gut flora and are, on the whole quite harmless while we are healthy. What triggers their antibiotic resistance is the exposure to the antibiotic itself.

Therefore, what is needed is a fast, cheap and efficient test that can be carried out by biomedical scientists, to identify these bacteria which show the potential to withstand antibiotics. If they are identified in the patient that require treatment then it would be best not to administer treatment with those antibiotics that have the potential to select for resistant strains but to use other antibiotic groups.

“So far we have been able to detect the carriage of various genes that encode for bacterial resistance in E.coli and coliform bacteria from the environment and from clinical isolates. We have also detected some strains that carry resistance genes but do not exhibit antibiotic resistance in the laboratory and one of our current studies is to see whether we can induce antibiotic resistance in these strains to enable us to further study and look how this occurs. These studies are time consuming and we are hopeful of some progress over the next two years. ”

Merfyn is also interested in researching how antibiotic resistance and genetic changes within these microbes can vary within populations of the same microbe. His team is also currently working on an epidemiological study, detecting and comparing differences in the genetics and antibiotic resistance of the same microbial family of bacteria found in North West Wales as compared to those in North East Wales

Merfyn Williams is also Director of the Biomedical Science degree at Bangor University and also works as a Senior Biomedical Scientist for Public Health Wales.

Publication date: 29 January 2015