HEALTH Project set to track body bacteria
Researchers studying disabled immune systems in bone-marrow transplant patients
A $400,000 pilot project is underway at Vancouver General Hospital to study how bone-marrow transplant patients rebuild an array of bacteria living in their bodies after invasive treatments knock it out.
Research on the human microbiome — the billions of microorganisms living in our gut, respiratory tract and on our skin — has exploded as its influence on our immune systems is unravelled.
The complex, two-year project is centred on three specially outfitted rooms at Vancouver General Hospital. It’s taking a multipronged approach by keeping air, water and surfaces in the room as sterile as possible while profiling the types of bacteria in and on the patients and their nurses.
Bone- marrow transplant patients are unique because they undergo chemotherapy and radiation that disable white blood cells and their infection-fighting abilities before an operation. After the transplant, antibiotics are prescribed to ward off infection which in turn wipe out many of the bacteria in their digestive tracts.
“We remove their normal immunity in order that they will accept the donor cells,” explained Dr. Elizabeth Bryce, regional medical director for Infection Prevention and Control at Vancouver Coastal Health, one of three researchers leading the work.
“That makes them very vulnerable because we’ve virtually wiped out their white blood cells and their immunity — and then it’s replaced.
“The question is, what happens to their microbiome? How is it influenced by the room they’re in and the health care staff they work with. This has not really been looked at before.”
THE ROOM
Hospitals are constantly looking for better ways to keep infections from spreading — most commonly with handwashing campaigns — but patient rooms in the study have an elaborate range of measures. Both the air and water are filtered and motion-detection devices eliminate water taps.
High-touch surfaces like table tops, bed rails, arm rests and toilet seats are covered with a germ-killing metal veneer made of copper and nickel.
Canada’s national body for evaluating health technologies, CADTH, reported earlier this year that antimicrobial copper and copper alloys kill 99 per cent of bacteria on their surfaces within two hours.
In the bathroom, an ultraviolet light will come on automatically to kill surface microorganisms when motion detectors confirm that there is no one in the room.
Much of the material and labour to refit the rooms has been donated by the makers of the metal surfaces and other devices to the tune of $80,000, notes Bryce.
THE SAMPLES
Between six and 10 transplant patients will be recruited for the research. They will receive treatment as usual with the addition of regular testing to gather microbes from their skin, nasal passages and stool samples.
The nursing staff will undergo similar tests to find out what bugs they are carrying. About 20 health workers will take part for each patient, and Bryce says they have been “wonderful” in stepping up for the research.
THE BUGS
All samples from patients and hospital staff will then go to the B.C. Centre for Disease Control for advanced genetic sequencing in which every organism — be it viral, fungal or bacterial — will be identified.
Medical microbiologist Dr. Linda Hoang, from the centre’s B.C. Public Health Lab, heads up the enormous work of creating a microbial profile for each person in the study, looking for any patterns of bugs being passed back and forth.
This team will also examine samples from the room — air, water and furniture swabs — for other clues.
THE BIG ISSUE
Healthcare-associated infections, also called hospitalacquired infections, cause an estimated 8,000 deaths per year in Canada. The World Health Organization says seven per cent of hospital stays in developed countries result in such an infection, rising to 10 per cent in the developing world.
They cost more than $15 million per year in the Vancouver Coastal Health regions alone.
The most well-known offenders are methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and Clostridium difficile or C. diff.
Intensive- care units have among the highest rates of infections, but studying bone-marrow transplant patients makes more sense because they are physically isolated, says Hoang.
The third lead researcher is Dr. Raewyn Broady, director of the Bone Marrow Transplant Program of B.C. The project is funded by Genome BC, the VGH and UBC Hospital Foundation, and the Public Health Agency of Canada.