Canada finds more infections with NDM-1 resistance factor

Nov 11, 2010 (CIDRAP News) – A recently identified enzyme that can make gram-negative bacteria resistant to nearly all antibiotics is back in the news with reports of several recent cases in Canada and two in Austria.

Five Canadians have had infections with bacteria carrying the NDM-1 enzyme in the past 3 months, bringing the country's total of such cases to eight, according to a Canadian Press (CP) report published today.

A report just published online by Emerging Infectious Diseases (EID) describes one of the Canadian cases, in a 76-year-old British Columbia woman who died of her illness. A second new report from EID describes the first two NDM-1 cases in Austria, involving a 30-year-old man who recovered and a 14-year-old boy who is still hospitalized.

NDM-1, which stands for New Delhi metallo-beta-lactamase 1, was first reported in 2009 but made headlines in August of this year with the publication of a Lancet Infectious Diseases report on resistant bacteria in India and the United Kingdom. The researchers found 136 NDM-1–producing isolates in India and Pakistan and 37 in the United Kingdom. Many of the UK isolates were in people who had traveled to India for medical treatment.

The authors reported that the isolates, mostly Escherichia coli and Klebsiella pneumoniae, were highly resistant to all antibiotics except colistin and tigecycline, both of which pose considerable risks. They said NDM-1 has a high potential to become a global public health problem, since few antibiotics for gram-negative bacteria are in the pipeline.

The first three NDM-1 cases in the United States were reported by the Centers for Disease Control and Prevention (CDC) in June. All of them involved patients who had received recent medical care in India.

Of the 8 Canadian cases recorded so far, 4 of the patients lived in British Columbia, 1 in Alberta, 2 in Ontario, and 1 in Quebec, according to the CP report. The Quebec patient, as well as the elderly British Columbia woman, died, but the resistant pathogen was not the direct cause of death in either case, according to Dr. Michael Mulvey, chief of antimicrobial resistance for the Public Health Agency of Canada, who was quoted in the story.

At least 5 of the 8 Canadians had traveled recently to India or Pakistan, and 4 of them had been hospitalized, the CP story said.

The 76-year-old from British Columbia fell ill with diarrhea during a 3½-month visit to India and was hospitalized for 3 weeks before returning to Canada, according to the EID report. In Vancouver she was put in an intensive care unit and treated for K pneumoniae and Clostridium difficile infections. She eventually died of what was described as toxic metabolic leukoencephalopathy, probably related to sepsis.

Two K pneumoniae isolates and one Escherichia coli isolate from the woman harbored NDM-1 and other resistance factors, the EID report says. Antimicrobial susceptibility testing showed that the isolates were resistant to multiple drugs.

Dr. Linda Hoang, a medical microbiologist at the British Columbia Centre for Disease Control, told the CP that Canadians shouldn't be worried about an outbreak of NDM-1 infections, because there is no evidence that NDM-1 bacteria are spreading in hospitals or in the community.

One of the two Austrian cases described in EID involved a man who was badly injured in a motorcycle accident in Pakistan and treated in hospitals in Pakistan, India, and Austria. During his hospitalization in Austria, highly resistant NDM-1-producing K pneumoniae isolates were found. He underwent 5 months of recurrent hospitalizations and various treatments before recovering.

The other Austrian case involved a 14-year-old boy from Kosovo who had abdominal sepsis after an appendectomy in his home country. When he was hospitalized in Graz, Austria, he was found to be infected with multidrug-resistant K pneumoniae at several sites. He remained hospitalized when the EID report went to press.

See also:

EID report on British Columbia case

EID report on cases in Austria

Nov 11 CP report

Abstract of Jun 2010 CDC report on first three US cases

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