More than 2,890 hospital patients in Canada are infected with a so-called “superbug,” or an antibiotic-resistant organism, at any one time, according to new Canadian research, which also found that most infections were acquired in a health-care facility.

The findings, released Monday and published in the journal Infection Control and Hospital Epidemiology, offer the first comprehensive look at the prevalence of superbug infections in Canadian hospitals.

According to the study:

  • 4.2 per cent of patients were carriers of or infected with methicillin-resistant Staphylococcus aureus (MRSA)
  • 0.5 per cent with vancomycin-resistant enterococci (VRE)
  • 0.9 per cent with Clostridium difficile (C. difficile)

In total, 1 in 12 adults in hospital either carried or was infected by one of the three superbugs, which are resistant to most antibiotics.

“They are often serious infections, often life-threatening and more difficult to treat,” lead study author Dr. Andrew Simor told CTV News.

The figures come from data gleaned in November 2010 from 176 acute-care hospitals that have at least 50 beds.

The study also broke down prevalence rates of each superbug across Canada. There was little difference in MRSA and C. difficile rates between provinces or regions of the country. However, VRE rates were much lower in Eastern Canada compared to other parts of the country. As well, C. difficile rates were lowest in Eastern Canada.

Researchers were not able to explain those differences.

Simor, chief of microbiology and infectious diseases at Toronto’s Sunnybrook Health Sciences Centre, said the study provides “a much-needed baseline” of infection rates that should guide the development of infection prevention and control policies. As well, the findings also serve as a warning that doctors must “use antibiotics wisely.”

Doctors say that the proper use of antibiotics in hospitals and in the community is critical to slowing the spread of treatment-resistant bugs. Inappropriate use can speed up antibiotics resistance.

“We are at a critical new point, where we need to encourage development of new drugs, but at the same time do everything we can to stop antibiotic resistant bugs from growing and spreading,” Simor told CTV.

Studies suggest that about 8,000 people die each year from hospital-acquired infections.

Carriers of superbugs often do not exhibit symptoms unless they have full-blown illness, but can still become sick themselves, as well as transmit the superbug to others.

With MRSA, for example, between one-quarter and one-third of carriers can become infected and develop either a form of pneumonia or an infection of the bloodstream. Between 30 and 60 per cent of patients with pneumonia brought on by MRSA and between 20 and 40 per cent of those with bloodstream infections will die.

The good news is that Canadian hospitals have lower rates of these antibiotic-resistant organisms than U.S. hospitals. However, there are higher rates in Canada than in European hospitals.

The study found lower rates of some superbug infections when patients carrying the organisms were isolated in private rooms, as well as in hospitals that had aggressive cleaning protocols -- though researchers say the study doesn’t confirm cause and effect. They say more studies are needed to strike the right balance between just how much cleaning keeps the most infections in check.

Dr. Joel Kettner, of the International Centre for Infectious Diseases in Winnipeg, called the study an important step in understanding the extent of this problem.

“We don't want to frighten or scare Canadians about hospitals,” Kettner told CTV. “ (But) we need to take it seriously, and see if the problem gets worse or stable.”

Kettner also noted that most people do not become seriously ill when carrying these bacteria, however, monitoring levels and how well precautions are working is important.

Researchers already conducted a second survey, in a similar number of hospitals, a few months ago. They are analyzing the data to see if these largely hospital-acquired infections are increasing or decreasing. That data will be made public in October.

Future surveys will also include other treatment-resistant infections, including NDM-1, a treatment resistant bacteria first seen 2009.

With a report from CTV’s medical specialist Avis Favaro and producer Elizabeth St. Philip

Have you contracted a hospital-acquired infection? Tell us in the comments section below.