Part III: The terrifying realities of antimicrobial resistance that will keep you up at night

As promised, today’s post will focus on the terrifying realities of antimicrobial resistance. I'm generally not an alarmist, but these two issues are Not Good. We are on our way to a post-antibiotic age of medicine.

The terrifying realities of antimicrobial resistance that will keep you up at night

CRE: Carbapenem resistant enterobacteriaceae This week, I saw headlines about a “nightmare bacteria” that killed two people and infected at least five more. Turns out the nightmare wasn’t such a surprise—the infections were caused by carbapenem-resistant enterobacteriaceae, or CRE.

Enterobacteriaceae are a family of bacteria that includes familiar disease-causing bugs including as Salmonella, E. coli, Enterobacter, and Shigella as well as other bacteria that don’t make us sick. In fact, some of the bacteria found in this family live benignly in the digestive tracts of humans and animals. Others, however, can cause serious illness or death.

What’s particularly frightening is that carbapenems, a particular class of antimicrobials, are usually used as the last-ditch effort to fight infection when other antimicrobials have failed. Bacterial infections treated with carbapenems are nearly always resistant to multiple other drugs. This means that if bacteria are resistant to carbapenems, they’re almost certainly resistant to all other antimicrobials. There are a few drugs that are used to treat CRE, though none of them are particularly effective. If those fail, you're in big trouble.

That’s right: CRE are resistant to basically every antimicrobial. If you get a CRE infection, your chances of survival are 50-50.

CRE are a serious threat to hospital patients. People are unlikely to come across CRE in their daily lives. However, people who are receiving hospital treatment are vulnerable to CRE infections.

I haven’t found any direct evidence linking CRE directly to animal agriculture. However, because carbapenem is only used when all other antimicrobials fail, if the bacteria weren’t already resistant, carbapenem wouldn’t have to be used in the first place! If you’d like to learn more, I recommend starting with Carl Zimmer’s piece “The ‘Nightmare Bacteria:’ An Explainer.”

Foodborne illness is a direct result of animal agriculture When you get food poisoning, it doesn’t matter whether the culprit is ground beef or cantaloupe: the microbes that traveled from your salad to your stomach came from the fecal matter of an animal. Maybe it was the cow you were eating, or one of its neighbors, or maybe it was an animal whose manure runoff contaminated the ground that the cantaloupe grew on. Either way, your gastrointestinal distress is tied directly to the bugs living in the digestive systems of agricultural animals.

CDC estimates that 48 million, or 1 in 6, Americans get a foodborne illness each year. Antimicrobial-resistant infections from food cause 430,000 illnesses each year in the US. Multi-drug resistant Salmonella causes 100,000 illnesses annually. Some strains of illness-causing microbes are becoming less resistant, while others are getting stronger.

A white paper from the Center for Science in the Public Interest shows a bleaker picture. It identifies 55 foodborne illness outbreaks from 1973 to 2011 that were associated with antimicrobial resistant microbes. Foods most likely to be implicated in these outbreaks were dairy, ground beef, and poultry. More than half of the outbreaks were due to multi-drug resistant microbes.

Maybe even more concerning is the fact that 58% of the outbreaks in that 38 year period occurred between 2000 and 2011. That’s right—more than half of foodborne illness outbreaks caused by drug resistant microbes since 1973 have occurred in the 21st century. The number of human illnesses caused by food contaminated by resistant microbes is on the rise.


This series has raised a lot of questions for me, and I plan to continue exploring this issue. Are there any related questions you’d be interested in having me research? I’ll totally do the work for you!


Special thank you to John Phillips for setting me straight on carbapenems. He's going to be a great pharmacist.

Part II: Evidence of the link between animal agriculture and antimicrobial resistance

Yesterday, I wrote about the basics of animal agriculture and antimicrobials. Today, I’ll dive deeper into the issues.

Part II: Evidence of the link between animal agriculture and antimicrobial resistance

What is antimicrobial resistance and why should I care about it? Antimicrobial resistance occurs when microbes have developed the ability to evade antimicrobials, survive antimicrobial treatment, multiply, and infect others. Microbes are able to survive partly because antimicrobial treatment may kill off the sensitive microbes and leave the more adapted ones to adapt to the antimicrobial and multiply.

Microbes can become resistant to multiple drugs. This makes the infection difficult or impossible to treat. By its very nature, an infection will spread to others, endangering more people with resistant infections.

The FDA has a pretty great video explaining the process of antimicrobial resistance.

Is there any evidence of association between antimicrobial use in animal agriculture and antimicrobial resistance in humans? Yes. Most of the evidence is based on studies of foodborne illness such as Salmonella and Campylobacter because the foodborne route is the most common way that resistant microbes are transferred from animals to humans.

Some resistant bacteria will themselves endanger human health. Others which cannot make humans ill will share their resistant genetic code with microbes that can make humans ill. These previously vulnerable, pathogenic microbes become resistant when they receive the resistant genes.

Using antimicrobials at sub-therapeutic levels to enhance growth means that all bacteria in an animal’s body is regularly exposed to low levels of antimicrobials. The most susceptible microbes will be killed or incapacitated, but the surviving ones will become increasingly resistant to the antimicrobial used.

How does using antimicrobials in animal agriculture contribute to human foodborne illness? The CDC report “Antibiotic resistance threats in the United States, 2013” outlines exactly how these two issues are related:

  1. Antimicrobial-resistant microbes may be formed through biological (e.g. selective pressure, mutations) or human (e.g. antimicrobial misuse, inadequate diagnostics) avenues.
  2. Antimicrobials used in animal agriculture kill off susceptible microorganisms while allowing resistant microbes to survive.
  3. Resistant microbes can be passed from animals to humans through fecal or other forms of contamination of food.
  4. When humans eat contaminated food, they develop infections (e.g. coli) that cannot be treated with antimicrobials. For generally healthy people, this may not be problematic, as their immune system will fight the infection itself. However, some people will need a boost from antimicrobials—antimicrobials that are now useless.

Beacause of this strong connection between animal antimicrobial use and human illness, CDC recommends that antimicrobials are used only to treat infections rather than to enhance growth. The CDC calls this antibiotic stewardship. 

What are some other ways animal agriculture-induced antimicrobial resistance affects human health?

  • Infections that would not have otherwise occurred
  • Treatment failures
  • Increased severity of infections (Source.)

Is animal agriculture the only cause of antimicrobial resistance? Definitely not. The other major contributor to antimicrobial resistance is improper human medical use. For example, when doctors prescribe antibiotics for a viral infection, the antibiotic will not treat the viral infection. However, the antibiotic may kill off a few bacteria from a minor bacterial infection, leaving only the remaining bacteria resistant to the drug.

 

Come back tomorrow for Part III: The Stuff That Will Keep You Up At Night

Part I: The basics of animal agriculture + antimicrobial resistance

Before antimicrobials, strep throat could be fatal. Nearly every child who had bacterial meningitis died. A small cut, once infected, could kill a person. In my mind, antimicrobials are neck-and-neck with vaccines and basic sanitation as the most important health and medical discoveries. And yet we are quickly losing our grasp on treating infections. Multi-drug resistant tuberculosis is on the rise, as is drug resistant gonorrhea, and MRSA strikes fear into anyone working or staying in a hospital.

Animal agriculture may have something to do with this. Antimicrobials are used extensively in the livestock and poultry industries. This piece is Part I of my exploration of the links between animal agriculture and the looming public health crisis of antimicrobial resistance.

The basics of animal agriculture and antimicrobial resistance

What is the difference between antibiotics and antimicrobials? Strictly speaking, an antibiotic is a substance produced by a microorganism that is used to kill or inhibit the growth of other microorganisms. Penicillin, grown from fungus, is an antibiotic.

An antimicrobial can be naturally-occurring, semi-synthetic, or entirely synthetic compound that it used to kill or inhibit the growth of other microorganisms. Antimicrobials include sulfonamides and amoxicillin. Antimicrobials can be used against bacteria, viruses, fungi, and protozoa such as malaria and toxoplasma gondii.

When discussing animal agriculture, the term antibiotic resistance is often used. However, because it doesn’t include synthetic or semi-synthetic antimicrobials, I’m going to follow the lead of the United Nations, the World Health Organization, and the World Organization for Animal Health and use antimicrobial resistance.

How are antimicrobials used in animal agriculture? Antimicrobials are primarily used as growth promoters and are given to livestock and poultry at sub-therapeutic levels, meaning that the levels at which the antimicrobials are administered are below the threshold that would fight off infection. Using antimicrobials as growth promoters is a direct result of the ever-increasing demand for meat and animal products.

Antimicrobials increase animal growth rate by 2-10% and feed conversion efficiency 3-9%. It’s unclear how or why this happens, but some researchers suggest that cytokines released when the immune system fights off infection may stimulate growth-inhibition hormones. Others suggest that antimicrobials keep animals’ gut bacteria in check, allowing the energy that would have been used to stave off infection to instead be used for growth.

Because nearly all animals raised for food are kept in cramped, stressful conditions, antimicrobials are also used for disease prevention and control (metaphylaxis). The animals live in such a way that makes infectious disease likely—packed in very closely, standing their own excrement—and rather than make changes to their living conditions, the various industries choose to feed the animals preventative antimicrobials.

Antimicrobials are also used when animals get sick, or after an injury or surgery. However, these uses make up just a small portion of the antimicrobials used.

Does animal agriculture really use 80% of the world’s antimicrobials? This statistic is often cited. However, there doesn’t seem to be much evidence to support it. However, this figure includes ionophores, which are not used in human medications but are used as growth promoters.

Which antimicrobials are used in animal agriculture? This table shows a selection of the antimicrobials identified as both critical to human medicine and regularly used in animal agriculture in the Congressional Research Service brief “Antibiotic use in agriculture: Background and legislation” by Geoffrey S. Becker. I added the columns “Common drugs in this class” and “Human infections treated by this class (selected).”

Antimicrobial class Common drugs in this class Human infections treated by this class (selected) Use in animal agriculture Level of importance for human medicine as defined by the FDA, based on level of difficulty of transmitting resistance across genera and species
Cephalosporin (3rd generation) Cedax, Fortaz, ceftriaxone Gonorrhea; urinary tract; respiratory; pelvic inflammatory disease; pneumonia Disease treatment in cattle and swine Critical
Fluoroquinolone Cipro, Floxin, Avelox Anthrax; hospital-acquired infections, especially pneumonia; urinary tract Disease treatment in cattle Critical
Penicillin penicillin, amoxicillin, flucoxacillin Meningitis; syphilis; Lyme disease; strep throat Disease treatment in cattle; growth and disease treatment in swine High
Macrolide Zithromax, erythromycin Legionnaire’s Disease; chlamydia Disease treatment and prevention in cattle; growth, disease treatment and prevention in swine Critical
Tetracycline doxycycline, tetracycline, Chlamydia; acne and rosacea; typus; plague Disease treatment and prevention in cattle; growth, disease treatment and prevention in swine High
Lincosamide clindamycin, lincomycin Toxic Shock Syndrome Disease treatment in swine High
Streptogramin pristinamycin, quinupristin Vancomycin-resistant Staphylococcus aureus (VRSA) and enterococcus (VRE) Growth, disease prevention in chickens High

How does antibiotic resistance happen? The National Institute of Allergy and Infectious Disease (NIAID) cites seven ways that microbes can become drug resistant:

Biological causes

  • Selective pressure: only the microbes with genes that make them resistant to antimicrobials are able to survive
  • Mutations: random changes in the genetic code protect some microbes from antimicrobials
  • Gene transfer: microbes can get genes from other, drug-resistant microbes

Human causes

  • Inappropriate use: prescribing antimicrobials for a disease that cannot be cured by them—for example, prescribing an antibiotic for a cold
  • Inadequate diagnostics: using a broad-spectrum antimicrobial when a specific one may be more effective, or being unsure of the underlying cause of illness and prescribing a drug “just in case”
  • Hospital use: hospital patients are susceptible to infections, but giving them high doses of antimicrobials puts them at risk for resistant infections
  • Agricultural use: NIAID states that agricultural use of antimicrobials is still debatable as a public health issue.

Now that we’ve covered the basics, check out Part II!

"Eating clean" is dangerous to your health

Clean eating salad Since becoming vegan last spring, I have found myself immersed in the “clean eating” community. There is a natural tendency, when you are constantly reading labels to figure out if there’s whey hidden in that loaf of bread, to become a little fixated on the contents of your food. I’ve witnessed--and granted, this is all online as I’m not overwhelmed with an abundance of vegan friends--a shift from reasonably avoiding animal products to becoming obsessed with eliminating every potential source of non-vegan ingredients. Sometimes, this obsession morphs into not only following a hyper-strict vegan diet, but avoiding GMOs, non-organic foods, artificial sweeteners, or anything else that can be perceived as impure.

But vegans aren’t the only people who are susceptible to buying into the idea of “eating clean.” And yes, I will continue to use quotation marks around it because I think the term is, well, bullshit.

The creeping realization that the Standard American Diet (SAD) is a major contributor to our problems with obesity, cardiovascular disease, cancer, and diabetes means that Americans are becoming increasingly health-conscious. About 1 in 5 Americans are on a diet at any given time, many of whom may be motivated by vanity but certainly some want to become healthier. Americans privileged enough to have the choice have been turning away from convenience foods and choosing “cleaner” options. Even Wal-Mart sells organic items now that many Americans are convinced that GMOs are dangerous to consume (even though scientists believe they’re safe to eat).

This focus on purity is troubling. It’s easy to go from wanting to do what’s best for your body to severely restricting your diet to becoming obsessed with consuming only the “cleanest” foods. The very idea that some foods are “clean” implies that some foods are “unclean”--and we’re not talking about bacterial contamination or visible dirt. This devolution is called orthorexia--an unhealthy fixation on health which can be characterized by an obsessive desire to “eat clean.”

Because orthorexia isn’t an official mental illness, I haven’t been able to find any statistics about the number of people who suffer from it. What I have found is an abundance of examples of people who demonstrate behaviors that are in line with the symptoms of orthorexia. As a woman in her late twenties who is (1) working in public health, (2) vegan, and (3) a trained cook always searching for a great recipe, I stumble upon what looks like orthorexia all the time. Fitness bloggers, oil-free vegan YouTube stars, and fitspiration creators on Tumblr and Pinterest all espouse eating philosophies that focus on finding only the “cleanest” foods.

The obesity crisis exacerbates this issue. Particularly in public health circles, there is an emphasis on encouraging healthy diets and plenty of exercise as a way of curbing Americans’ collective weight gain. In fact, I began my MPH thinking I would become a nutrition and food educator (though my focus has shifted over time). Because obesity-related health conditions are a strain on quality of life and an economic burden, public health has rightfully invested resources in reducing obesity in our population. But the constant messages to “Make half your plate fruits and vegetables” can easily become, in the minds of those who are vulnerable to obsessive thinking, “The only way to eat clean is to only eat fruits and vegetables” or “Oil is evil.”

This is not to say that we shouldn’t be eating more produce. Absolutely, Americans should be. But I believe there’s a need to be sensitive to the diverse way healthy eating messages will be interpreted. The dangerous concept of “eating clean” is rampant and can have negative consequences for anyone concerned with achieving or maintaining health. Public health professionals should keep this in mind.

And if you’d like, I’m happy to make you some vegan chocolate chip cookies with real sugar, white flour, and lots of fat. I may not eat animal products, but that doesn’t mean I "eat clean."

The Conclusion of Teagan Goes Vegan

bananas  

So, the month of “Teagan Goes Vegan” has come to a close. In this episode, I talk about the experience: what I ate, what I missed, how my friends reacted. And I reveal whether I will be staying vegan or not!

Action Phase is on iTunes. Subscribe so you never miss an episode. Ratings help other people find the show and have the added benefit of giving me a little ego boost!

You can also stream the episode here.

[embed]https://ia902508.us.archive.org/6/items/28-TeaganGoesVeganConclusion-ActionPhasePodcast/28-TeaganGoesVeganConclusion-ActionPhasePodcast.mp3[/embed]

Action Phase Podcast Episode 27

VforVeg1004_400I talk with Lydia Chaudhry of the Humane League, sponsors of the first ever Philly VegFest. She tells me about her journey into veganism and animal activism and the Meatless Monday campaign. We also discuss vegan dining out and which restaurants we love.

Action Phase is on iTunes. Subscribe so you never miss an episode. Ratings help other people find the show and have the added benefit of giving me a little ego boost!

You can also stream the episode here.

[embed]https://ia902500.us.archive.org/25/items/27-LydiaChaudhry-ActionPhasePodcast/27-LydiaChaudhry-ActionPhasePodcast.mp3[/embed]

Action Phase Podcast Episode 26

johnrossi_headshotJohn Rossi is an Assistant Teaching Professor in Bioethics and Public Health Ethics as well as a veterinarian. He gives me an excellent introduction to animal ethics and the public health implications of animal agriculture, as well as sharing his personal story of following a vegetarian/vegan diet. Special thanks to Phoebe for connecting me with John.

Action Phase is on iTunes. Subscribe so you never miss an episode. Ratings help other people find the show and have the added benefit of giving me a little ego boost!

You can also stream the episode here.

https://ia902506.us.archive.org/24/items/26-JohnRossi-ActionPhasePodcast/26-JohnRossi-ActionPhasePodcast.mp3

Vegan restaurant review: Charlie was a sinner.

As part of Teagan Goes Vegan, I’m taking a little step outside my normal public health topics to tell you about my experience at the new vegan bar/restaurant in Philadelphia called Charlie was a sinner.  

Pros: delicious food, impeccable service.

Cons: dimly lit, loud music.

Charlie was a sinner

When I heard that a new vegan bar opened last week, I recruited my foodie friend for a visit. The bar/restaurant is at 13th street and Sansom and is called Charlie was a sinner. (yep, that’s the correct capitalization and the period is supposed to be there). It’s owned by the mastermind behind HipCityVeg, Nicole Marquis, and the kitchen is headed up by Mike Santoro.

 

When I got there at 5:45pm the dining room was mostly empty. My server came to my table immediately. He asked if I preferred still or sparkling water, and brought me a carafe of fizzy water stuffed with fresh mint leaves. It’s a really lovely touch that will only be more appealing as the summer heats up. I got a Unibroue Ephemere Apple, one of my favorite beers, which was not only on tap but very reasonably priced. The cocktails, though they looked delicious, were out of a grad student’s price range at $12 each.

 

I caught the tail end of happy hour, so I ordered some half-price toasts: Our Ricotta and Wild Mushrooms & Barley. The Our Ricotta toasts have a tofu-based ricotta spread drizzled with sweet jam and served alongside tender, crisp bread. Very tasty—most people would have trouble identifying it as non-dairy. The Wild Mushrooms & Barley toasts were by far the best dish we had. The ale sauce was rich and savory, the mushrooms were tender and earthy, and the barley provided chewy texture.

 

My friend ordered the Potato Croquettes. She declared that they were more like tater tots than croquettes because they were made of shredded rather than pureed potatoes. She’s right, and a simple menu change would fix that misleading name. The smoked paprika aioli rivaled any mayo-based sauce, and was perfectly spiced.

 

We finished up with the Chickpea Fries. They were disappointing. They looked and smelled like frozen French toast sticks, and tasted oddly sweet. The spring garlic aioli was bland, almost like a dollop of plain Vegenaise.

 

The service was even better than the food. Our server not only kept our glasses full and our plates cleared, but he took a few minutes to tell me about the history of the building—it was a brothel, and then a seedy hotel—and to talk with me about veganism. He recommended books and a podcast to help me in my vegan experiment. After my friend arrived, he was attentive but knew to hang back and not interrupt our conversation too much (a part of service often lacking in Philadelphia's restaurants).

 

The restaurant was unnecessarily dark. The music was also turned up a little too high, especially as tables filled up and patrons talked loudly. These are both simple fixes that could be quickly addressed, and certainly shouldn’t dissuade you from going.

 

Though it’s only been open a few days, by the time we left, every table was full. I suggest trying Charlie was a sinner. as soon as you can, because as more people hear about it, it’s going to be tough to get a table after 6pm. I will definitely be back.

 

You can check out their menu here.

Teagan Goes Vegan Week 1: Eating Well, Making Decisions

I made it through the first week of Teagan Goes Vegan. I thought you may be interested in how things are going.  

So far, I haven’t had many food cravings, probably because I’ve been eating full meals and being sure to snack. During the first two days, I was really hungry, but I think I’ve rectified it by having bigger, more calorie-dense breakfasts than I’m accustomed to eating. I have been carrying around little packs of almonds, Larabars, and baby carrots just in case hunger strikes. Something tells me that if you look in any vegan’s backpack, you’ll find those same foods.

 

I’ve been tracking my food intake to be sure that I’m keeping a balanced diet and that I’m meeting my calorie needs. According to the USDA and DHHS Dietary Guidelines for adults:

  • 45% to 65% of calories eaten should come from carbohydrates.
  • 20% to 35% of calories eaten should come from fat.
  • 10% to 35% of calories eaten should come from protein

I’ve been aiming for staying in the middle of these percentages—50% from carbohydrates, 30% from fat, 20% from protein. So far, I’m doing pretty well hitting those goals. Here are two screen shots of my nutrition profile from Thursday, May 8.

vegan_calories_wk1 vegan_nutrition_wk1

I’ve also been taking a B vitamin supplement, since B12 is the one vitamin that cannot be found in plants, only in animal products. The other major supplements that vegans often take are calcium/vitamin D, iodine (usually through iodized salt), and iron. I’m not planning to supplement those at this point, though I'm following my intake closely and if I find I'm low on more days than not, I may start.

 

Grocery shopping has been an adventure. I started at Whole Foods, because I knew I could get lots of vegan products there. Though I’ve been a label reader for years now, I realized how closely I have to read them now. This meant I had to make some decisions about what I was going to avoid.

 

I chose to:

  • I am avoiding foods that may contain milk or eggs, even if there is no discernible milk or eggs in the ingredients list, but not avoid foods that have been processed in a facility that processes dairy or eggs.
  • I am not avoiding some of the additives that can be animal-derived, such as lecithins and monoglycerides.
  • I am not buying convenience foods just because they’re vegan. I didn’t eat chicken patties, frozen pizza, or breakfast sandwiches before I started this experiment, so I shouldn’t start now. I did buy some vegan soups in case of emergencies.
  • I will still consume non-vegan alcohol. For example, many brewers use isinglass, derived from fish swim bladders, to clarify beers. As my friends know, Nathan and I keep a well-stocked bar in our house, and a girl can only make so many changes in one month.
  • I will also consume processed sugar, even though some refined sugar is processed with bone char, though in general I try pretty hard not to eat too much added sugar.

 

This week has gone well. I’m eager to see how Week 2 shakes out. Want to know more? Ask me questions in the comments and I’ll be happy to share my experiences.

 

Action Phase Podcast Episode 25

allyson kramer headshotI kick off the first week of "Teagan Goes Vegan" with Allyson Kramer, vegan and gluten-free cookbook author and blogger. She talks with me about nasty blog comments about vegetable oil, the privilege inherent in deciding to be vegan, and how paleo diets are surprisingly similar to vegan ones.

Action Phase is on iTunes. Subscribe so you never miss an episode. Ratings help other people find the show and have the added benefit of giving me a little ego boost!

You can also stream the episode here.

https://ia902504.us.archive.org/7/items/25-AllysonKramer-ActionPhasePodcast/25-AllysonKramer-ActionPhasePodcast.mp3