Analysis of the genome sequence of one of the bacteria living in the human gut should help to identify those more at risk from bacterial infections after intestinal surgery.
The focus of the genome study, which involves researchers from Queen's University Belfast and the Sanger Centre in Cambridge, is Bacteroides fragilis. The Bacteroides family is one of the major groups of bacteria that inhabit the human body, particularly the colon.
Most of the time B fragilis is of great benefit to the human body and aids the process of excluding food poisoning bacteria such as salmonella from the intestinal tract. The main problem arises if it escapes from the gut following for example a ruptured appendix or abdominal surgery, Dr Sheila Patrick of the Department of Microbiology at Queen's explained.
"This opportunistic pathogen is the main anaerobe, a bacterium that lives in the absence of oxygen, observed in peritonitis. It has the potential to severely limit the success of gastro-intestinal surgery," Dr Patrick stated.
Prior to the introduction of antibiotics, mortality from infection arising from colonic perforation was between 30 and 100 per cent. This was largely due to a lack of knowledge about the role of anaerobes, bacteria that can survive in the absence of oxygen, in these infections and a lack of treatments.
Now there are antibiotics that will keep peritonitis under control. Dr Patrick believes however that antibiotic resistance is now a growing problem.
If resistance to the antibiotics used in the treatment of peritonitis was to develop it would seriously reduce the amount of abdominal surgery being carried out. "It would be impossible to offer the patient the same level of protection during and after surgery."
One way to defeat an enemy is to understand it better. Dr Patrick is one of the main researchers involved in an initiative to sequence the genome of B fragilis as a way to gain this knowledge. Dr Patrick is an expert on B fragilis, having studied it since 1981.
It is hoped that the sequencing of B fragilis will help create an understanding of how the bacterium operates. This will enable researchers to target areas unique to the bacterium but not to the host and get information about the molecules that allow the infection to develop.
"The human genome project will also change the way we look at all types of bacterial infection," Dr Patrick said. "When combined with the whole area of bioinfomatics, we will be able to match knowledge of bacteria with knowledge of the human genome and see why some people are more susceptible to infectious diseases than others," she explained.
The B fragilis genome is being sequenced at the Sanger Centre, Cambridge, UK, using DNA from Dr Patrick's laboratory at Queen's. Dr Patrick believes that knowledge of the genome sequence will potentially revolutionise the understanding of the virulence of this microbe. The sequence information can be viewed via the Welcome Trust Beowulf Genomics and Sanger Centre web sites:
http://www.beowulf.org.uk/home.htm
http://www.sanger.ac.uk/projects/microbes/