A Belfast scientist believes her research could help reduce the risk of deadly infection after stomach surgery.
Bacteroides fragillis lives in the colon
Dr Sheila Patrick, from Queen's University, has discovered how the bacterium responsible fools the body's defences.
Bacteroides fragillis lives in the colon and can cause infections if it escapes as a result of surgery, a burst appendix or childbirth.
By mapping its genes she hopes new drugs could help neutralise its effect.
The bacterium makes up as much as half of human faeces. Although it helps with digestion and fights against food poisoning bacteria such as salmonella, it can cause serious infections.
Before effective antibiotics were available, up to a third of infections from this bug proved fatal.
Now some resistant bacteria have appeared and there is concern that resistance may spread, as it has with other types of bacteria.
As part of her research, Dr Patrick has discovered why molecules on the surface of the bacterium are so variable.
With the Pantogen Sequencing Unit at the Sanger Institute in Cambridge, she has been analysing and mapping all the genes of the B. fragilis genome. Over 4,000 genes have been identified.
According to Dr Patrick, the variation in the bacterium is caused by inversion of bits of the DNA. No other bacterium is known to use this same mechanism so extensively.
"The link between bacteria and disease was first proven at the end of the 19th century, so we have come a long way in just over 100 years," she said.
"Because of these and other complete bacterial genome sequencing projects, we are at the start of a revolution in our ability to understand what makes bacteria tick and also our ability to combat those that cause disease."