Superbugs

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Special Series: Fast Forward

Antimicrobial Resistance

By David Kattenburg

The American nation is in a “moment of crisis,” Donald Trump declared, as he launched into his nomination acceptance speech at the Republican National Convention in Cleveland last week. “The attacks on our police, and the terrorism in our cities, threaten our very way of life.”

America faces numerous frightful threats, said Trump: terrorism, immigrants, crime, violence, gangs, drugs, lawlessness, government regulation, media elites; the growing reputation for being weak. Nowhere in his 4300-word screed did Trump have anything to say about multidrug-resistant bacteria.

 

A serious gap in his threat assessment. According to the US Center for Disease Control, an estimated two million Americans get infected by antibiotic-resistant bacteria each year — among these “superbugs” that no antibiotic can arrest — and at least 23,000 end up dying. Visions of a future where lots and lots of Americans die from routine infections or seemingly insignificant scrapes, a return to pre-antimicrobial centuries, do not seem to trouble Trump.

McMaster University microbiologists Eric Brown and Gerry Wright (David Kattenburg)

McMaster University microbiologists Eric Brown and Gerry Wright (David Kattenburg)

They should. A 2013 CDC report identified eighteen drug-resistant bacterial species, assigning them to three threat categories — “urgent,” “serious” and “concerning.”

Among the urgent threats:

  • Gut bacterium Clostridium difficile causes potentially fatal diarrhea among a half million Americans each year, and kills 15,000, at an estimated billion dollar cost to the health care system. Almost four billion could be saved over five years by countering the C. diff. threat, the CDS says.
  • Carbapenem-resistant Enterobacteriaceae (Klebsiella, E. coli) are responsible for 9000 drug-resistant infections annually, and 600 deaths, particularly within US health facilities. Blood-borne infections have a fifty percent mortality rate. “CRE have become resistant to all or nearly all the antibiotics we have today,” the CDE says.
  • Of the 820,000 gonorrhea infections in the US each year, a quarter million are drug-resistant.
  • Drug-resistant pathogens the CDC considers “serious” or “concerning: the humble yeast Candida (denizen of human urogenital tracts), the common hospital bug Pseudomonas, the common but potentially opportunistic skin resident Staphylococcus aureus; also drug-resistant Streptococcus pneumoniae and tuberculosis.
Dr. John Embil, Infection Prevention and Control Unit, Winnipeg Health Sciences Centre

Dr. John Embil, Infection Prevention and Control Unit, Winnipeg Health Sciences Centre

Of course, antibiotic resistant bugs are nothing new. Alexander Fleming, the discoverer of penicillin, observed the phenomenon back in the late twenties. Darwinian theory (which many Trumpsters deny) in action.

As bacteria split in two at their customary pace, replicating their chromosomes at each round (gut bug E. coli divides every twenty minutes on standard growth medium), DNA errors crop up. These are called mutations. Most bacterial mutations neither help nor harm a microbe. An estimated one in ten million bacterial cells will spin off a mutation that renders them antibiotic-resistant. In the absence of a given antibiotic, that mutation serves no purpose and may actually be a burden. It costs energy and material to produce the protein it codes for.

But douse the bug with antibiotic, and this mutation — a “resistance gene” — places its owner at a “selective advantage.” Impervious to the antibiotic, the bacterium divides and divides (while its non-resistant neighbors die) and now you’ve got a population of drug-resistant bugs.

Dr. Ayush Kumar, University of Manitoba

Dr. Ayush Kumar, University of Manitoba (David Kattenburg)

The most threatening, drug-resistant bacteria are resistant to three classes of antibiotics (as defined by their mode of action or bacterial target). The baddest bugs of the bunch are unbeatable. They can block, pump out, or degrade any antibiotic we’ve got to throw at them. “They just scoff” at drugs, says McMaster University Gerry Wright in this audio doc. Click on the SoundCloud link above.

The good news: It’s antibiotic use that promotes the spread and acquisition of drug-resistant infection. Stop prescribing antibiotics, and drug resistance-conferring genes will “wash out,” says Wright. Drug-resistant bugs will always be present. You can’t get rid of them.

But we can reduce their numbers. Here’s how:

  • Ill people can opt to avoid antibiotics. Most respiratory or GI infections resolve naturally. That’s what acute infection is all about. If antibiotics are prescribed, people should take their full drug course, rather than stopping when they think they feel better. Stopping in the middle, before pathogens are squashed, promotes resistance.
  • Physicians can stop prescribing antibiotics for flu infections (antibiotics don’t kill viruses). When a bacterium is to blame, doctors can prescribe narrow, rather than broad-spectrum antibiotics, thus reducing selective pressure on resistance genes.
  • Avoid antimicrobial household products. They cause more harm than good. As discussed in the audio doc above, antimicrobials like Triclosan are ubiquitous: in cutting boards, tooth paste, undershirts. Their presence promotes the development of multi-drug resistance. Their use should be reduced or eliminated.
  • Get antibiotics out of the livestock and fish farming industries.

The last of this list may be the most critical and challenging measure to be taken in the fight against superbugs. A 2004 report by the Cambridge, Massachussetts-based Union of Concerned Scientists estimated that 25 million pounds of antimicrobials were being administered to livestock annually, the vast majority for non-therapeutic purposes. That is to say, simply to promote animal growth.

Eric Brown & Gerry Wright (David Kattenburg)

Eric Brown & Gerry Wright (David Kattenburg)

Twelve years later, the tonnage of antibiotics administered to US and Canadian livestock has surely grown. Astonishingly, US and Canadian farmers are free to administer antibiotics for prophylactic and growth promotion reasons without a veterinary prescription. Here in Canada, farmers are able to purchase antibiotics in the States and bring them into Canada, no questions asked.

In 2014, in regard to the “complex and evolving public health issue” surrounding antimicrobial use in livestock, Health Canada announced that its Veterinary Drugs Directorate was now “engaging provincial/territorial authorities, the pharmaceutical industry, veterinarians, food animal producers and other stakeholders” to promote the reduction of non-therapeutic antibiotic use. Health Canada would be “moving forward,” the announcement stated, together with the Canadian Animal Health Institute.

How far Canada has moved forward on this issue in the past two years is unclear. Judging from an analysis by CBC Medical Science reporter Kelly Crowe at the time of Health Canada’s announcement, it may not be very far.

Listen to the voices in this audio doc. Decide for yourself where multi-drug resistance ranks in the list of crises facing Donald Trump’s America, and the world, today.

Fast Forward: Stories of Challenge & Change is produced with the generous support of the Government of Canada, the Social Justice Fund of Unifor, and the Community Radio Fund of Canada. Thanks to Roger Dumas for his wonderful human brain ‘sonifications’, one of which appears in Fast Forward intros/extros. For more information about Roger’s Pieces of Mind CD, go here.

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