Canada’s anti-superbug initiative
Canada’s federal government is launching an initiative to combat antibiotic resistant bacteria. This is a very sensible thing to do, given how bacterial evolution is creating resistant strains at a higher rate than the one at which we are inventing new antibiotics. MRSA and its relatives could well signal a return to a world in which morbidity and mortality from bacterial illness start shifting back towards the levels prevalent before antibiotics were widely available.
We largely have ourselves to blame for the existence of these bugs. Every time a doctor prescribes unnecessary antibiotics in order to get a patient out of their office, we give them another chance to get stronger. The same goes for when a patient stops taking an antibiotic prescription when they feel better, rather than when it runs out, potentially leaving a few of the most resistant bugs behind to infect others. The same is true for all the ‘antibacterial’ soaps and cleaning products out there. Putting triclosan in soap is pretty poor prioritization. Outside the body, it makes the most sense to kill bugs with things they cannot evolve resistance to: like alcohol or bleach. Using the precious chemicals that kill them but not us to clean countertops is just bad thinking. Finally, there is the antibiotic-factory farming connection discussed extensively here before.
The federal plan involves a number of prudent steps, many of them specifically targeted to MRSA and Clostridium difficile. These include more active patient screening, better sanitization of hospital rooms, use of prophylactics like gloves and masks, and the isolation of patients with resistant strains. Given that there were 13,458 MRSA infections in Ontario hospitals in 2006, it seems that such an initiative is overdue. It would be exceedingly tragic if we comprehensively undermined one of the greatest discoveries in the history of medicine through carelessness and neglect.
February 4th, 2008 at 1:41 pm
Defenceless against influenza
National Post Published: Monday, February 04, 2008
The World Health Organization announced mystifying news last week: The garden-variety influenza virus H1N1 that periodically besets the world, and is doing so this winter, seems to be developing a startling new resistance to Tamiflu (oseltamivir), the first and most important of antiviral drugs for influenza.
That such a thing should happen is curious. No one bothers much with Tamiflu as a primary weapon of attack against the regular flu– at least not outside Japan, where aggressive marketing by a subsidiary of the global patent-holder, Hoffman-La Roche, has convinced the populace to more or less pop the stuff like candy. For flu programs in nursing homes and hospitals elsewhere, other antivirals come a lot cheaper and work just as well.
February 5th, 2008 at 10:42 am
Epidemic community-associated methicillin-resistant Staphylococcus aureus: Recent clonal expansion and diversification
Emerging and re-emerging infectious diseases, especially those caused by drug-resistant bacteria, are a major problem worldwide. Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) appeared rapidly and unexpectedly in the United States, resulting in an epidemic caused primarily by isolates classified as USA300. The evolutionary and molecular underpinnings of this epidemic are poorly understood. Specifically, it is unclear whether there has been clonal emergence of USA300 isolates or evolutionary convergence toward a hypervirulent phenotype resulting in the independent appearance of similar organisms. To definitively resolve this issue and understand the phylogeny of USA300 isolates, we used comparative whole-genome sequencing to analyze 10 USA300 patient isolates from eight states in diverse geographic regions of the United States and multiple types of human infection. Eight of 10 isolates analyzed had very few single nucleotide polymorphisms (SNPs) and thus were closely related, indicating recent diversification rather than convergence. Unexpectedly, 2 of the clonal isolates had significantly reduced mortality in a mouse sepsis model compared with the reference isolate (P = 0.0002), providing strong support to the idea that minimal genetic change in the bacterial genome can have profound effects on virulence. Taken together, our results demonstrate that there has been recent clonal expansion and diversification of a subset of isolates classified as USA300. The findings add an evolutionary dimension to the epidemiology and emergence of USA300 and suggest a similar mechanism for the pandemic occurrence and spread of penicillin-resistant S. aureus (known as phage-type 80/81 S. aureus) in the 1950s.
February 18th, 2008 at 9:16 pm
Tracking global E.coli ‘crucial’
A system must be set up to monitor the global spread of a drug-resistant form of E.coli which can cause fatal blood poisoning, Canadian scientists urge.
March 23rd, 2008 at 5:45 pm
Meat wagon: pork superbug!
May 27th, 2008 at 4:57 pm
The Pink-Bubble-Gum- Flavored Dilemma
Why doctors give out antibiotics you don’t need.
By Zachary Meisel
Posted Wednesday, May 21, 2008, at 3:21 PM ET
The profligate prescription of antibiotics—for children and adults with upper respiratory infections, sinus infections, and even middle-ear infections—is a problem because most of these illnesses are caused by viruses, not bacteria, which are what conventional antibiotics attack. Of more concern is the direct connection between antibiotic use and the emergence of drug-resistant “superbugs”: As the medicine eliminates germs that are sensitive to it, drug-resistant mutant strains prosper. The result is a major public-health problem. Antibiotic-resistant infections such as methicillin-resistant Staphylococcus aureus may cause more deaths in the United States than AIDS does.
In the doctor’s office or the ER, it’s hard to tell the difference between bacterial and viral infections, and so doctors are tempted to prescribe antibiotics whenever they’re unsure. That’s especially true when doctors think that patients expect to take the medicine home, according to a recent study. Investigators interviewed patients with respiratory infections who went to the ER in 10 hospitals affiliated with medical schools, asking whether the patients expected to receive antibiotics and about whether they were satisfied with the care they received when they were discharged. The researchers also asked physicians why they prescribed antibiotics. The main conclusion was that doctors were significantly more likely to prescribe if they believed that patients expected them to—but did a lousy job predicting which patients those actually were. And the patients most satisfied with their care were the ones who left the ER with a better understanding of their condition, antibiotics or no antibiotics. The take-home message for doctors like me: Spend an extra five minutes talking to your patients about their medical problems, and you can send them away happy and without unnecessary medicine.
June 26th, 2008 at 10:23 am
In the presence of drugs, pathogens have evolved sophisticated mechanisms to inactivate these compounds (e.g. by pumping out compounds, mutating residues required for the compound to bind, etc.), and they do so at a rate that far exceeds the pace of new development of drugs. Examples include drug resistant strains of Staphylococcus aureus, Klebsiella pneumonia, and Pseudomonas aeruginosa, and Mycobacterium tuberculosis (TB) among bacterium and HIV-1 among viruses. Indeed, no new antibiotics have been developed against TB in thirty years. Efforts to develop new antibiotics by the pharmaceutical industry by large-scale screens of chemical libraries which inhibit bacterial growth have largely failed, and new tetracycline and sulfanilamide analogs will likely engender resistance and will quickly be rendered useless.
June 26th, 2008 at 10:28 am
Vancomycin-resistant Staphylococcus aureus
August 11th, 2008 at 12:37 am
The new generation of resistant infections is almost impossible to treat
By Mark Frauenfelder
I’ve read a lot of stories about antibiotic-resistant infections, but this New Yorker piece by Jerome Groopman called “Superbugs” stands out.
Frederick Ausubel, a bacterial geneticist at the Massachusetts General Hospital, in Boston, is searching for drugs to combat bacterial virulence, using tiny animals like worms, which have intestinal cells that are similar to those in humans, and which are susceptible to lethal microbial infection. The worm that Ausubel is studying, Caenorhabditis elegans, is one and a half millimetres in length. “You are probably going to have to screen millions of compounds and you can’t screen millions of infected mice,” Ausubel said. “So our approach was to find an alternative host that could be infected with human pathogens which was small enough and cheap enough to be used in drug screens. What’s remarkable is that many common human pathogens, including Staphylococcus and Pseudomonas, will cause intestinal infection and kill the worms. So now you can look for a compound that cures it, that prevents the pathogen from killing the host.”
August 26th, 2008 at 7:49 am
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