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Superbug: What you need to know

Is this new superbug the end of the world? No, says ASU researcher.
May 31, 2016

ASU researcher explains how realistic all those "end of the world" headlines are

Last week the Department of Defense issued a report detailing the case of a 49-year-old Pennsylvania woman who had a rare E. coli infection resistant to all antibiotics, including colistin, which is a harsh drug used only on the sickest patients.

The superbug is the first known case of its kind in the United States, and the report sparked strong reactions. The concern was that traits of the infection could jump to other bacteria that respond only to colistin, creating an unstoppable superbug.

ASU Now talked with Dr. Shelley E. Haydel, an associate professor in the School of Life SciencesThe School of Life Sciences is an academic unit in the College of Liberal Arts and Sciences. and a researcher in the Center for Infectious Diseases and Vaccinology at the Biodesign Institute at Arizona State University, about how realistic the threat is.

Question: The World Health Organization said the superbug is the biggest threat to global health.

Answer: I wouldn’t say that. A couple of the headlines were quite misleading. I don’t remember all of them, but they were all —

Q: We’re going to die.

A: “We’re going to die and it’s not treatable.” That’s not true. If I could explain as simply as possible what was in the paper that came out that caused all these headlines, and why it’s not the end of the world as we know it related to microbiotic resistance, and why some of the information from that report is important, and why it’s not the end of the world.

Everyone has a chromosome, including you and me. Bacteria have these little small plasmid DNA molecules, separate from the chromosome. These can be passed into another bacterium. The chromosome can’t, but these can be passed easily. This is one of the ways antibiotic resistance is spreading rapidly.

What this paper showed is that one of the last-resort antibiotics, which is called colistin, for the first time they found the resistance gene for colistin on a plasmid. Previously the resistance gene had always been in the chromosome. So, mutations that occur in the chromosome, I can’t pass that. I can’t pass that to anyone, but these plasmids I can.

ASU associate professor Shelley E. Haydel

ASU researcher Shelley E. Haydel. Photo by Deanna Dent/ASU Now

One of the reports actually described colistin resistance in CRE. CRE is one of the big issues in antibiotic-resistance bacteria because of this first C, which stands for carbapenem. Carbapenem is part of a group of antibiotics that are reserved for people in ICU, who are really, really sick.

Q: Heavy-duty stuff.

A: Heavy-duty stuff, and we really didn’t see that before the last five to 10 years. It was our best antibiotics that work against a lot of different bacteria, so save those for the sickest people. Now we have resistance to carbapenems. So what we’re seeing in the carbapenem-resistant Enterobacteriaceae — which is what the E stands for — this is the only antibiotic that would work for patients with CRE.

Now, this antibiotic was taken off the market 50 or 60 years ago because it destroyed your kidneys. Now we’ve gone back to that antibiotic because it was the last remaining antibiotic that could be used to treat patients with CRE. Have we seen patients with CRE and colistin resistance? Yes. The strain in the Pennsylvania woman, she was not resistant to carbapenems. Is it bad? Yes, because we’re seeing colistin. And it’s on a plasmid. Could that plasmid get into CRE streams? Absolutely.

So, a little bit of issue related to the headlines: It wasn’t colistin and colistin resistance in a CRE strand of bacteria; there are antibiotics that were still active against her infection. It’s the colistin resistance on that plasmid, meaning eventually we’re going to see it.

Q: Has this come about by overprescribing antibiotics, or people becoming more resistant by having more antibiotics in their systems?

A: Both. Antibiotic stewardship is that basically people demand antibiotics for viral infections, people demand antibiotics for everything, and it’s a matter of not prescribing antibiotics when they’re not needed. We have millions of infections each year that aren’t caused by bacteria but antibiotics are administered. It’s problems associated with the genetic passage of DNA between the organisms; the best way to confer resistance is to pass a little DNA. Exposure of the organisms to antibiotics used in livestock — it’s a combination of all of those things.

Q: That’s true; they’re pumping cows and chickens full of everything.

A: They’re healthier and they’re fatter and they’re bigger and they make more money from the meat.

Q: So it’s not all the fault of doctors? We can lay some of the blame on farmers as well?

A: Farmers and patients. One of the stories I read in the past was a mom or dad who has been dealing with a baby who has been crying for two weeks because they have an ear infection or a viral infection and they’re at their wit’s end and they go in and demand antibiotics. The justification is that it’s a viral infection but maybe that baby will get a secondary infection, so here’s your prescription for antibiotics. Part of it is to get that patient out of the door. They think it’s going to help, and most of the time you ask that mom or dad did it help, and they’re going to say yes. Did it help? Probably not, because it never was a bacterial infection.

But that’s a placebo effect on mom or dad. Eventually the viral infection in children, babies, adults, you’re going to get better over time. It might’ve been that two-week time when it was about to get better and the antibiotics just happened to be available at that given time. That’s a big education point. You hear about it every time it’s in the news: Antibiotics do not work against viral infections. If you have a cold, don’t take an antibiotic. If you have the flu and feel awful, antibiotics won’t work.

Q: So your coach’s old advice wasn’t so bad after all — spit on it and take a lap.

A: That’s right.

Q: What’s going to be a solution? A bigger gun?

A: Inevitably a new drug — a new miracle drug that will generate resistance to it.

Top photo: A closeup of E. coli, which is an example of Enterobacteriaceae, a normal part of the human gut bacteria, that can become carbapenem-resistant. Carbapenems are a class of broad-spectrum antibiotics. Courtesy of the National Institute of Allergy and Infectious Diseases.

Scott Seckel

Reporter , ASU Now


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Effects of marijuana on health, finances

Marijuana use leads to few physical health problems, ASU researcher finds.
Marijuana use increases risk of IQ, socioeconomic decline, says ASU researcher
June 1, 2016

ASU researcher’s team finds that cannabis use may not cause physical health problems but does increase risk of IQ decline, downward socioeconomic mobility

As states increasingly legalizeAt last count, 24 states and the District of Columbia have legalized the use of marijuana in some form. Four states and the District of Columbia have legalized it for recreational use. the use of marijuana, the debate surrounding its benefits vs. risks wages on. There is still much unknown about the effects of cannabis.

Thanks to the research of ASU assistant professor Madeline MeierMadeline Meier is an assistant professor in the Department of Psychology, an academic unit of ASU’s College of Liberal Arts and Sciences., though, we are closer to understanding how marijuana affects three key things: IQ, physical health and socioeconomic mobility.

In 2012, Meier and colleagues published a report in the journal PNAS indicating that adolescents who use marijuana for many years show a drop in IQ from childhood to adulthood. This research has influenced public policy, particularly decisions to keep marijuana out of the hands of teens. Now in 2016, Meier answers the question of whether long-term marijuana users are in worse physical health. It turns out that they are not.

Her research“Associations Between Cannabis Use and Physical Health Problems in Early Midlife: A Longitudinal Comparison of Persistent Cannabis versus Tobacco Users” published this month in the journal JAMA Psychiatry shows that aside from having bad teeth, marijuana users have few physical health problems at midlife. For example, marijuana users did not have worse lung function, higher levels of inflammation or worse metabolic health than non-users.

ASU assistant professor Madeline Meier in her office.

Assistant professor of psychology Madeline Meier’s latest research on long-term marijuana use aside from having bad teeth, persistent marijuana users have few physical health problems at midlife. However, her other research has shown marijuana’s detrimental effects on key social and financial factors. Photo by Charlie Leight/ASU Now

This latest finding comes on top of another paper“Persistent cannabis dependence and alcohol dependence represent risks for midlife economic and social problems: A longitudinal cohort study” published in Clinical Psychological Science in March, in which Meier and colleagues found that persistent cannabis use is associated with worse socioeconomic outcomes. 

Study participants who reported using marijuana regularly (four or more days per week) showed a drop in social class compared with their parents. A standardized measure of social class was used, looking at things like a participant’s credit score, whether they relied on government assistance and the amount of debt they had.

The results were then controlled for potential alternative explanations. For example, one alternative explanation could have been that participants who reported regular use of marijuana showed a drop in social class not because of their marijuana use but because they had been incarcerated.

To test that possibility, the team members analyzed a subset of participants who had never been incarcerated. They found that even among that subset, a drop in social class was still observed among those who had regularly used marijuana.

“What this shows is that incarceration cannot explain marijuana users’ drop in social class,” said Meier.

On the flip side, Meier and her colleagues were also able to determine that participants who had never used marijuana actually ended up in a slightly higher social class than their parents.

Meier’s work on IQ, physical health and socioeconomic mobility was based on the same datasetThe Dunedin Multidisciplinary Health and Development Study of more than 1,000 New Zealanders followed from birth to age 38.

“We used the same sample, followed over the same time frame, and we found that marijuana is associated with adverse effects in some domains but not others,” said Meier.

Given her findings, Meier says we can’t label marijuana as “good” or “bad” for someone. It’s not that simple.

“It’s pretty clear that marijuana use increases risk for psychosis and can impair cognitive functioning, but marijuana use may not cause physical health problems, at least by midlife,” said Meier.

Emma Greguska

Reporter , ASU Now

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