Maryn McKenna

Journalist and Author

New England Journal editorial: MRSA, H1N1 parallels

By Leave a Comment

There’s a very interesting piece in a recent New England Journal of Medicine (unfortunately, only the abstract is online) that draws parallels between MRSA and public expectations for pandemic flu. Written by Dr. Kent Sepkowitz, chief of infection control at Memorial Sloan-Kettering Cancer Center in New York and one of the authors of the “Medical Examiner” column at Slate, it’s an exploration of microbial sleight of hand: We were looking in one direction for a problem to develop, and — like Wile E. Coyote staring after the Road Runner but missing the Acme anvil — the problem came around and socked us in the back of the head.

In the case of flu, Sepkowitz writes, we concentrated on the threat of H5N1 avian influenza — the focus, until H1N1/swine flu arrived, of billions of dollars and years of effort in pandemic preparation — but were surprised by the sudden catastrophic emergence of seasonal flu strains resistant to oseltamivir (Tamiflu), one of the few antiviral drugs that can reduce illness and death from flu if taken early enough. In the case of MRSA, medicine focused on containing the spread of hospital MRSA and its rare transformation into VRSA, vancomycin-resistant staph — and mostly discounted, until far too late, the enormous threat of community MRSA strains:

The intensity of our concern and the frequency of the doomsday dispatches were appropriate. We were simply chasing the wrong microbe. It is community-acquired MRSA, not VRSA… that now occupies the center of the public health stage. And just about everything predicted for VRSA has come true for community-acquired MRSA. It’s everywhere; it’s deadly; it has changed the day-to-day management of skin infections and pneumonia in clinics, emergency rooms and intensive care units. It’s a true public health disaster. It’s just a different disaster from the one we were exercised about.

As we wrangle the new threat of H1N1, Sepkowitz warns that it is vital to remember how many millennia of practice microbes have in foiling our expectations:

We should marvel at the raw, restless power of microbes. They have the numbers — trillions and quadrillions and more that replicate wildly, inaccurately and disinterestedly. Nothing microbes do, whether under the duress imposed by antimicrobials or from some less evident pressure, should surprise us. It’s their world; we only live in it.

(Image courtesy Sansceo Design)

Media round-up: recommending MRSA stories

By Leave a Comment

By chance — or is it because interest is really picking up? — a couple of worthwhile stories on MRSA have been published almost simultaneously:

  • For when the science gets wonky: Environmental Health Perspectives has an excellent lay-language explanation of how drug resistance emerges and spreads — with gorgeous graphics!
  • For when yet another drug doesn’t work: Scientific American covers development of new antibiotics, and even more important, development of new ways of creating antibiotics.
  • For yet more depressing news about MRSA in meat: Prevention adds to the discussion of MRSA in the food supply with a “special report” review. Constant readers who have been following along as we’ve drilled into this topic over the past two years won’t find a lot new, except for an intriguing account of an outbreak of MRSA in an Arkansas chicken plant (in which the bug went disappointingly untyped, so we don’t know whether it was a human strain or ST398). The story hits on issues we have talked about here: Surveillance for MRSA in animals is non-existent, practically speaking, and when the bug is found, investigation falls between human and animal health agencies. It’s a longer than usual story for Prevention, and should bring the knotty food-policy questions around MRSA in meat to a new audience.

Antibiotic overuse in animals: Obama administration comes out against

By Leave a Comment

For anyone who cares about the overuse of antibiotics in food animals, and the resistant bacteria that overuse has been shown to produce, this is important news.

In testimony today, new FDA Commissioner Dr. Joshua Sharfstein announced the administration’s opposition to the use of growth promoters: sub-therapeutic doses of antibiotics used not as disease treatment, but to encourage animals to put weight on rapidly. Further, he also came out against the administration of antibiotics in food animals without the involvement of a veterinarian — a common situation out here in farm country, where veterinary antibiotics are freely available over the counter. (We discussed Scott Weese’s proposal to end that practice here.)

Both of these practices have been repeatedly linked to antibiotic resistance, and for the administration to come out against them is highly significant — not just for the struggle against resistant bacteria, but also for the movement to reduce industrial-scale agriculture, which relies on antibiotics to keep food animals healthy while they are in the close confinement of CAFOs.

Sharfstein made the announcement while giving testimony on behalf of Rep. Louise Slaughter (D-NY)’s Preservation of Antibiotics for Medical Treatment Act of 2009, which has been introduced (and opposed into nonexistence) multiple times over the past decade. (Earlier post on the legislation, including its text, here.) He said:

To avoid the unnecessary development of resistance under conditions of constant exposure (growth promotion/feed efficiency) to antibiotics, the use of antimicrobials should be limited to those situations where human and animal health are protected. Purposes other than for the advancement of animal or human health should not be considered judicious use. …
Important factors in determining whether a prevention use is appropriate include evidence of effectiveness, evidence that such a preventive use is consistent with accepted veterinary practice, evidence that the use is linked to a specific etiologic agent, evidence that the use is appropriately targeted, and evidence that no reasonable alternatives for intervention exist. FDA also believes that the use of medications for preventino and control should be under the supervision of a veterinarian. …
FDA supports the treatment of ill animals according to appropriate veterinary practice within a valid veterinary-client-patient relationship.

Also on the docket at Slaughter’s hearing:

  • Margaret Mellon, PhD, of the Union of Concerned Scientists (who specifically discussed MRSA ST398): “As long as the massive use of antibiotics continues, animals … will remain a fountain of resistant pathogens, dangerous to both animals and humans. The straightforward solution to the problem is to reduce the use of antibiotics in animal production and thereby diminish the pool of resistant organisms and traits.”
  • Robert Martin of the Pew Environment Group (Pew Charitable Trusts): “The present system of producing food animals in the United States is not sustainable and presents an unacceptable level of risk to public health, damage to the environment, as well as unnecessary harm to the animals we raise for food.”
  • And statements of support from the Chipotle restaurant chain and the Bon Appetit Management Company (which operates catering services in corporations and universities).

Of note, the Pew Commission on Human Health and Industrial Farming, which supports Slaughter’s bill, said after the hearing that Sharfstein’s proposals are only necessary but not sufficient: ““The proposed FDA position does not go far enough in this regard and would allow the continuation of conditions that necessitate the improper use of antibiotics in the first place.”

Food and ag policy sites: New in the blogroll

By Leave a Comment

Folks, when I was writing the last post (regarding Scott Weese’s blog), I had to stop and look up several sites. In mid-click, I realized how silly that was, because they are sites I visit all the time — and you should too, if you’re concerned about the veterinary, zoonotic, agricultural and food-policy issues that we discuss here so frequently.

So I’ve created a new category in the blogroll to the right, showcasing food and ag-policy sites that I think are worth reading. Among them you’ll find:

If you have other recommendations, please send them!

Restricting antibiotics in animals: Start by restricting access

By Leave a Comment

Constant readers, those of you who follow the pressing issue of MRSA in animals will know the work of J. Scott Weese, DVS, associate professor of pathobiology at the University of Guelph in Ontario and supervising author of many crucial papers on MRSA in food and companion animals, including the first finding of MRSA in pigs and pig farmers in North America.

You may not know that Weese and his postdoc Maureen Anderson publish an excellent blog on veterinary and zoonotic diseases called Worms and Germs (in the blogroll at right). This weekend they have an important post that deserves wider attention: Antibiotics: A Dose of Common Sense. In it, they propose that one way to reduce the overuse of drugs in food animals is to make animal antibiotics prescription-only. It’s worth taking the time to read it.

Those of you in the cities may not know this, but out here in the Great Flyover, antibiotics for veterinary use are surprisingly easy to buy (as I discovered when I stumbled into a farm-related store in search of a Carhartt jacket against the Minnesota winter). They’re not even over-the-counter — they’re on the shelf, or stacked on the floor with the implements and feed, or blended into the feed itself. And as Weese points out in this post, they are also available without prescription over the Internet (as human antibiotics are too).

It’s a potentially controversial proposal: I don’t think I have any farming readers, but I would imagine their response would start with an objection to the extra cost of hiring a veterinarian to assess whatever situation might require the drugs. And since most farmers (NB: not the overarching ag-biz companies, but the farmers themselves) exist on razor-thin economic margins, they would have a point. But as we know from the excellent work of Extending the Cure and the Center for a Livable Future, unnecessary antibiotic use comes with a cost as well — one that is borne by all of us when antimicrobial resistance prevents antibiotics from working.

MRSA strains crossing borders: US CA-MRSA to Italy

By Leave a Comment

Swine flu continues to dominate the headlines, but other pathogens don’t read the papers. Case in point: New news about a US community strain being found and treated in a woman in Italy — better treated, as it turns out, than she was in California, where she was infected.

In a new letter in Emerging Infectious Diseases (a free journal published online and in print by the CDC — it’s your tax dollars at work, just read it, already), Carla Vignaroli, Pietro E. Varaldo, and Alessandro Camporese of the Polytechnic University of Marche in Ancona amd the Santa Maria degli Angeli Regional Hospital, Pordenone report the case of

a 36-year-old Italian woman (who) was seen at Pordenone Hospital (northeastern Italy) for spider-bite–like skin lesions on the face, characterized by rapid evolution to furuncles and small abscesses. The infection had started ≈1 month earlier in California, where she had spent several months on business (wine import-export), and where she had been treated empirically with amoxicillin/clavulanate for 10 days (1 g, 3×/day), with no clinical improvement.

(At this point, I know every clinician reader and everyone who has had a MRSA skin infection is shaking his or her head. Surely by now the knowledge that “spider bite” is practically diagnostic for CA-MRSA has penetrated? But apparently not, since she was given amoxicillin/clavanulate, AKA Augmentin, which is partially penicillin-based.)

When the woman’s lesions were cultured, they turned out to be caused by USA400, the original community strain, which back in the 1990s was known as MW2. That’s interesting, especially in California, since USA300 has become such a dominant strain. Nevertheless, the key point is that USA400, as with USA300, has barely been recorded in Italy:

All 3 previously reported cases of CA-MRSA infection in Italy were caused by type IV SCCmec, PVL-positive strains, none of which, however, belonged to the ST80 clonal lineage that predominates in Europe (7). The first case (in 2005) was a necrotizing pneumonia caused by an ST30 isolate; the 2 other cases (2006) were severe invasive sepsis and a neck abscess, both caused by ST8 (USA300) isolates.

The concern, of course, is that once imported, they will not remain rare:

The case we note here documents the importation of a US pathogen into a country in Europe, from an area where the pathogen is widespread and has been highly virulent since the late 1990s, to an area where its penetration in the past has been poor.

The cite is: Vignaroli C, Varaldo PE, Camporese A. Methicillin-resistant Staphylococcus aureus USA400 clone, Italy [letter]. Emerg Infect Dis. 2009 Jun; [Epub ahead of print]. DOI: 10.3201/eid1506.081632

Does ethanol production produce resistant bacteria too?

By Leave a Comment

One of the challenges of disappearing down the rabbit hole of a gnarly chapter — gee, it’s dark down here — is that I get behind on my RSS feeds, and suddenly every entry in my Google Reader is at 1000+ and it’s all just too daunting.

So, trying to catch up a bit, I found two related, interesting and troubling stories from the Associated Press (4 April) and the online magazine Grist (7 April — yes, I said I was behind…).

Synopsis/synthesis: Corn-based ethanol, former darling of the energy and large-scale agriculture industries, suddenly doesn’t look like such a good idea – and not just because the market for it is crashing. Turns out that ethanol is made by adding yeast and sugar to corn mash; the yeast convert the carbohydrates to the alcohol that is the basis of the fuel. (Yes, just like making beer.) However, the mash is particularly attractive to Lactobacillus and other bacteria that produce lactic acid as a waste product rather than alcohol, and a tank full of lactic acid doesn’t make very good fuel. So, to keep the bacteria under control, ethanol producers add antibiotics. Specifically, penicillin and erythromycin — you’ll recognize those — and tylosin and virginiamycin, two macrolides, related to erythromycin, that are approved in the US for veterinary use.

Now, the problem with this practice, as you might predict, is that if the mash is not appropriately dosed, the presence of antibiotics within it can prompt some of the bacteria to develop resistance. (Here’s an article from the trade magazine Ethanol Producer discussing just that possibility.)

And the further complication of this is that the leftover mash, now called “distillers’ grains,” is sold as animal feed. Ask yourself: Where in animal production are animals most likely to eat grains? Answer: At finishing, in feedlots. In other words, fermented grains that may contain antibiotic residue, and may contain resistant bacteria, are being sold as feed to animals that are already being raised in conditions that have been shown to foster the development of resistant bacteria through subtherapeutic and prophylactic antibiotic use. In fact, some research has drawn an explicit link: Kansas State University scientists have found higher levels of E. coli O157 in the guts of cattle that were fed distillers’ grains.

All of this was new to me, but there’s an additional facet to the story that the AP and Grist pieces don’t highlight, and that just makes my head hurt: the use of virginiamycin. For those new to the story, virginiamycin is an allowed, widely used veterinary antibiotic in the US. However, it is not used in the European Union: It was banned there in 1998 because the EU’s ag authorities believed that it promoted resistance to the drug Synercid (quinupristin+dalfopristin), which is a drug of last resort against vancomycin-resistant bacteria such as VRE. (Here’s a Lancet paper that talks about that resistance mechanism.) Synercid was approved by the FDA in 1999 — two years after Synercid resistance had already been found in the US. (For a long but cogent explanation of the complex story of virginiamycin, see the book The Killers Within.)

So, just to recap: We have an industry whose long-term earnings are shaky, whose economic survival is partially secured by the sale of its waste product, and which via that waste product is putting antibiotic residues and antibiotic-resistant bacteria into the environment, and is conveying them into food animals, and is making particular use of an antibiotic that other countries have banned because they believe that, via its use in animals, it exerts an adverse impact on human health.

Something to remember the next time ethanol subsidies come up.

How sewage plants birth resistant bacteria

By Leave a Comment

At the always-excellent public health blog Effect Measure, there’s a fascinating dissection of a new paper still in press at the journal Science of the Total Environment. The paper unpacks what happens to Acinetobacter in effluent as they move through sewage treatment. Answer: Many are eliminated, but the ones that survive become significantly more resistant.

I am deep in the final book chapter, so blogging will be light for a week. In the meantime, I recommend this paper and the accompanying post for explicating a little-explored aspect of antibiotic resistance in the environment (which we also talked about in this earlier post.)

The cite is: Zhang, Y. et al. Wastewater treatment contributes to selective increase of antibiotic resistance among Acinetobacter spp. Sci Tot Env doi:10.1016/j.scitotenv.2009.02.013.

Back soon.

More MRSA in pigs, in Portugal

By Leave a Comment

A brand-new report, in a letter to the International Journal of Antimicrobial Agents, indicates that ST398 “pig MRSA” has been found in Portugal for the first time.

Constanca Pomba and colleagues from the Technical University of Lisbon swabbed and cultured the noses of pigs and veterinarians on two pig farms in different regions of Portugal, and also checked the air at both farms.

What they found:

  • On Farm A: All pigs and the veterinarian positive for ST398, the pig-origin strain that has been found so far in Iowa, Ontario, the Netherlands, France, Denmark, Germany and Austria and has, depending on the country, caused human disease and/been found on retail meat. The veterinarian was transiently colonized, which is to say that he was not carrying the bug long-term.
  • On Farm B: All pigs — but neither of two veterinarians — positive for a different MRSA strain, CC (or ST) 30. This is very interesting, because CC30 is usually a drug-sensitive strain (MSSA, methicillin-sensitive S. aureus), and has been found in pigs primarily in Denmark and France. In Portugal, it is a human MSSA hospital-infection strain.

Strains from both farms were resistant to tetracycline; this is turning out to be a great marker for these strains having emerged due to antibiotic pressure in animals, because tetracycline is very commonly used in pigs. but not much used for MRSA in humans. The strains have the genes tetK and tetM, so they are resistant not just to tetracycline itself, but to the whole class of tetracyclines including doxycycline and minocycline. The Farm B strains also carried the gene ermC, which encodes resistance to erythromycin.

So what does this tell us?

  • First, that (once again), every time people look for ST398, they find it; it is now a very widely distributed colonizing bug in pigs, and is repeatedly spreading to humans. What we don’t know, because all these studies are so new, is whether ST398 is actively expanding its range, or has been present in all these countries for a while. We have been anticipating its presence or spread (take your pick at this point) through the European Union because of open cross-border movement of food animals, meat, and agriculture and health care workers.
  • And second, it should tell us that it is really past time to start looking for this more systematically. Every finding of ST398 that we have (long archive of posts here) is due to an academic research team who decided to look for the bug. None of the findings, to date, have come from any national surveillance system. (NB: Except for the first human colonizations in the Netherlands, which were found as a result of the national “search and destroy” rules in hospitals.)

Of note, the European Union is running a study now that is supposed to report ST398 prevalence at any moment (as they have been saying since 2007). It is not expected to be comprehensive, since it was piggy-backed onto another study, but it is something. The US government has not been so enterprising.

The cite is: Pomba, C. et al. First description of meticillin-resistant Staphylococcus aureus (MRSA) CC30 and CC398 from swine in Portugal. Intl J Antimicrob Agents (2009), doi: 10.1016/j.ijantimicag.2009.02.019

MRSA news from Europe – Society for General Microbiology

By Leave a Comment

The annual meeting of the UK’s Society for General Microbiology is taking place this week, so here’s a quick roundup of MRSA-related news. As with these posts from a year ago, abstracts are not online; in a few cases there are press releases from the science-news service EurekAlert.

  • MRSA-colonized patients who have been identified in a hospital by active surveillance culturing may not need to be isolated to prevent their bacteria being transmitted to other patients by healthcare workers — provided hospital staff and visitors adhere to very vigorous handwashing. (P. Wilson, University College Hospital, London; press release)
  • An engineered coating made of titanium dioxide with added nitrogen could be employed as an antibacterial surface in hospitals; exposure to ordinary white light activates the compound to kill E. coli and may be useful against MRSA also. (Z. Aiken, UCL Eastman Dental Institute; press release)
  • The natural antiseptics tea tree oil and silver nitrate enhance bacterial killing when combined, which may also allow them to be used in lower doses – important for avoiding toxicity. It may also be possible to deliver them encapsulated in engineered sphere made of lipids called liposomes. (W.L. Low, University of Wolverhampton; press release)
  • Overuse of antibiotics in farming is not only breeding resistant bugs in animals, it is also changing soil ecology and depleting nitrogen-fixing bacteria that improve soil fertility. The antibiotics are affecting soil when manure from drug-using farms is spread as fertilizer. (H. Schmitt, University of Utrecht; press release)

Bill in Congress: “Preservation of Antibiotics for Medical Treatment” Act

By Leave a Comment

Important news for anyone concerned about the spread of “pig MRSA” ST398: Rep. Louise Slaughter (D-NY) and Sen. Edward Kennedy (D-MA) have introduced a bill that would restrict important classes of antibiotics for use against disease only, taking them out of the realm of subtherapeutic use or growth promotion in agriculture. The bill would allow the use of the antibiotic classes for disease in animals as well as in humans; the intent is to preserve the drugs’ effectiveness for as long as possible.

The text of the bill, the Preservation of Antibiotics for Medical Treatment Act of 2009, is here.

A Reuters story in which Slaughter predicts the bill will have a difficult time is here; she has introduced it several times in the past decade, but it has never made it through.

Support from the Pew Commission on Industrial Farm Animal Production is here. An earlier version was supported by the American Academy of Family Physicians here.

The National Pork Producers’ Council’s response is here.

(Hat tip to Barry Estabrook at Politics of the Plate and to Melinda Hemmelgarn, the FoodSleuth.)

Ten tips for avoiding hospital infections

By Leave a Comment

ScientificAmerican.com (disclosure: I have written a story for them, and it is edited by a friend) has a great interview with a hospital epidemiologist about things to do to avoid hospital infections.

It’s a smart list, with some non-obvious things on it. For instance:

5. Make sure you’re kept warm
The air temperature in operating rooms typically hovers between 65 and 69 degrees Fahrenheit (18 and 20 degrees Celsius). That’s great for the doctors and nurses bundled head to toe in scrubs, but not necessarily for the person on the table. [Stephen Streed, an epidemiologist who oversees infection control at the Lee Memorial Health System in Fort Myers, Fla.] says that the body responds to chilly air by constricting vessels supplying blood to the skin and the tissues just below it; diverting blood away from the body’s surface and toward its core is the body’s strategy for conserving heat. With less blood supplying oxygen to the incision site, the immune cells there become oxygen-deprived and therefore less effective at battling invading germs. Ask the surgical team how they intend to keep you warm — if they will crank up the room temperature by a few degrees, cover you in blankets, or warm you with IV fluids, for instance.

6. Ask about presurgery antibiotics
For many operations, including those involving the heart and bone, doctors routinely give patients preventive antibiotics to nip infections in the bud. One dose is typically given via IV an hour before the surgeons make the first cut, and sometimes two more doses are given over the next 24 hours, Streed says. If you think there is any possibility that you have an infection before going into surgery, tell your doctor so that he or she can treat you first. (Having an existing infection in, say, the bladder or skin ups the risk of developing a second, surgery-related infection, Streed warns.)

The whole list is worth reading.

New York Times takes up “pig MRSA” ST398

By Leave a Comment

Constant readers, I know that many of you are very interested in ST 398, the “pig strain” of MSRA that has caused both mild and life-threatening human infections in Europe and has been found in retail meat in Canada and on farms and in farmers here in the Midwest. So I just want to bring to your attention that New York Times columnist Nicholas Kristof takes up the topic today, in the first of two promised columns: Our Pigs, Our Food, Our Health.

In today’s piece, he describes an apparent epidemic of skin and soft-tissue infections in a pig-farming area of Indiana that caught the attention of a local family physician, who subsequently died.

What we’d need to know, of course — and may never know, given that the investigation may have ended with the doctor’s death — is what strain of MRSA those local folks had. They may have ST 398, picked up if they worked on farms, or if it migrated out of the farms via groundwater or dust or flies. Or they may have USA300, the human community-associated strain, which in some areas is astonishingly common — a fact that most people don’t appreciate if they have heard only about the invasive child-death cases or the outbreaks in sports teams.

The full archive of posts on MRSA in animals is here and stories only about ST398 are here.

Industrial farming, bacterial spread 2 – or: Flies. Ick.

By Leave a Comment

There’s a brand-new paper in the journal Science of the Total Environment that has some unnerving things to say about the link between very large scale farming, use of antibiotics in food animals, development of resistant organisms, and transmittal out into the larger environment.

Via flies.

Not to be unscientific, but: Ick.

A team from the Bloomberg School of Public Health at Johns Hopkins (who have done a number of studies on the spread of antibiotic-resistant organisms from farms to the outside world) decided to test the links in a chain of hypothesis that goes like this:

  • Antibiotics are used in large amounts in poultry production.
  • Antibiotic-resistant organisms are produced within the birds.
  • Antibiotic-resistant organisms leave the batteries via poultry litter (“excreta, feathers, spilled feed, bedding material, soil and dead birds“).
  • Poultry litter is stored in open sheds until it can be used as a soil amendment.
  • Flies have unrestricted access to poultry litter.

The tests were: sampling poultry litter from three farms in the Delmarva Peninsula (for non-US readers, that’s a portmanteau word for contiguous areas of the states Delaware, Maryland and Virginia, home to about 600 million chickens each year); trapping flies at 8 locations within 100 meters of farm boundaries; and assaying both litter and flies for the presence of resistant organisms and resistance genes.

And the findings were: Oh, lots and lots. Litter piles at all three farms contained resistant organisms — E. faecium, E. faecalis and our particular interest, Staphylococcus (multiple species, including three strains of S. aureus) — throughout the 120-day study period. All 8 fly traps did as well. All of the litter contained enterococci and staph strains that were resistant to 3 or more antibiotic classes. Seven of the 8 fly traps yielded multi-drug resistant enterococci, and 3 yielded multi-drug resistant staph. The resistance factors identified were for drugs that the FDA classifies as “critically or highly important” to human medicine: “penicillin, tetracyclines, macrolides, lincosamides, aminoglycosides and streptogramins.” Oh, and the fly species captured in the traps had an average range of 2 miles.

Of note, among the isolates discovered was one staphylococcus with high-level resistance to vancomycin.

The authors say:

This study strongly suggests that flies in intensive poultry production areas, such as the Delmarva Peninsula, can disperse antibiotic resistant bacteria in their digestive tracts and on their exterior surfaces. Dispersion of resistant bacteria from poultry farms by flies could contribute to human exposures, although at present it is difficult to quantify the contribution of flies. Flies may also transfer bacteria from fields amended with poultry waste.

The cite is: Graham JP et al., Antibiotic resistant enterococci and staphylococci isolated from flies collected near confined poultry feeding operations, Sci Total Environ (2009), doi:10.1016/j.scitotenv.2008.11.056. The ahead-of-print abstract is here.

Industrial farming, bacterial spread – another connection

By Leave a Comment

We’ve talked a lot here about the spread of MRSA ST 398, the “pig strain,” subsequently found in other animals and in retail meats in various countries; and also about the likelihood that antibiotic use in large-scale farming fosters the growth of resistant organisms; and also about the way that resistant bacteria from large-scale industrial farms end up in the larger environment via groundwater and airborne dust. (Use these links to call up all the ST 398 stories and related agriculture and food stories.)

Here’s an emerging story that should illuminate some of the dangers we are discussing. Note, it’s not about MRSA, and it’s not about resistant organisms, but it is an object lesson on how industrial-size farms can spread bacteria through the environment.

Last year, there was an outbreak of an unusual type of E. coli — a strain called O111 — in Oklahoma. There were 341 known cases, 72 hospitalizations, one death. The outbreak centered on a Locust Grove, OK restaurant called the Country Cottage, which used a private well. Here’s the Oklahoma State Department of Health wrap-up of that outbreak; no source for the E. coli was ever identified.

Now comes the Oklahoma Attorney General to say that the source has been identified: Poultry DNA has been found in wells in the area, and the AG contends it is because of the use of poultry litter — manure, feathers, the stuff that falls to the bottom of a chicken house — as fertilizer on local fields.

Now, some cautions: There is no indication in the media reports (I’m looking for a report or release from the AG’s office but haven’t found one) that the particular E. coli strain has been found; that outbreak has burned itself out. And also, the Oklahoma AG has apparently been fighting with the poultry industry and the state of Arkansas for several years over poultry-litter pollution in the Illinois River watershed. The poultry industry, naturally, disagrees that this practice is a health threat.

But if the Oklahoma AG is correct, and there is evidence that poultry manure is putting pathogens into the water supply far from poultry farms, then that would be one more link in the chain of evidence that connects industrial-scale farming, agricultural antibiotic use, development of resistant organisms, presence of those organisms in the environment, and human health effects.

Do not, do not, do NOT do this

By Leave a Comment

Hi from down the rabbit hole, readers (is there an echo?) — I am deep into a chapter and not surfacing much. Therefore, I’m once again behind in my reading, and so just stumbled across this from last week: a New York Times article called out by Liz Borkowski on the excellent public health blog Pump Handle.

The NYT story — which ran in the New York regional section and thus may not even have made it (on paper) out here to the Great Flyover — is primarily about young adults going naked on health insurance, what happens when that goes wrong, and how they practice a kind of do-it-yourself medicine to cope. But what made Liz’s hair stand on end (and mine, now that I’ve read it), is the way that the characters describe taking each other’s unused antibiotics:

Nicole Polec, a 28-year-old freelance photographer living in Williamsburg, Brooklyn, said she has attention deficit hyperactivity disorder and has a client who procures Ritalin on her behalf from a sympathetic doctor who has seen Ms. Polec’s diagnosis. Ms. Polec’s roommate, Fara D’Aguiar, 26, treated her last flu with castoff amoxicillin — “probably expired,” she said — given to her by a friend. (Byline: Cara Buckley)

You all got what was going on there, right? Flu — or even a cold — is a viral illness. Antibiotics don’t work against viruses. But antibiotics taken inappropriately do contribute to the evolution of drug-resistant bugs everywhere, and do make you more vulnerable to such bugs if they wipe out your own protective bacterial flora.

(NB: Let’s be clear, by criticizing this, I do not at all mean to be unsympathetic to the plight of the uninsured. My brother, a film composer, has been uninsured his entire career; as a freelancer, I have insurance only by the generosity of my in-all-ways-excellent spouse. And, just to editorialize, I consider it an international embarrassment that, what, one-sixth? of our population lacks the ability to pay for their health care. But there are things that are smart to do, in coping with the unworkability of the American health care system, and there are things that are not smart. Under-dosing and self-mis-dosing are, categorically, not smart.)

If you have time, please go read Liz’s analysis, it’s very good. If you don’t, please just listen to this take-away message: DON’T DO THIS. (Sorry to shout.)

Bad news from Australia: MRSA in water supplies

By Leave a Comment

The Brisbane Courier-Mail reports that scientists in Australia have found MRSA and VRE from hospital sewage in rivers and lakes throughout the state of Queensland, and have been trying for two years to get their provincial government to pay attention.

Secret tests on waste water discharged from 28 Queensland hospitals and clinics revealed the widespread presence of MRSA (Methicillin resistant Staphylococcus aureus) and VRE (Vancomycin resistant Enterococci).
However there was no evidence the potentially lethal organisms had made their way into drinking water.
A Central Queensland University scientist who helped carry out the research told me 97 per cent of hospital sewage discharge lines tested positive for antibiotic resistant bacteria.
He said 70 per cent of hospital discharges tested positive for both MRSA and VRE.
“We got a lot more of those bacteria than we thought possible,” he said. … “Even though they have passed through a treatment process, the bacteria are most likely getting back into natural waterways, dams and ponds used for swimming, boating, fishing and in food production.” (Byline: Des Houghton)

The report was presented to the Queensland parliament by a member in 2007, ignored, and presented again last week. (Note for US readers who click through to the story, from my UK childhood: “Tabled,” in parliamentary parlance, means “brought forward” or “introduced” — not “postponed” as we would interpret it.)

The wastewater was treated in a sewage plant and then tested — but the usual tests look for enteric pathogens such as E. coli, not for MRSA, so the water passed testing without MRSA’s presence being detected.

There have been similar studies in Portugal, South Africa and Nigeria. In the US, MRSA and other resistant bacteria have been found in groundwater and airborne dust, but that has been due to leakage from industrial farming. I’m not aware of anyone doing this sort of study, with organisms escaping from hospitals, in this country. If anyone does know of one, and has a cite, please comment!

More MRSA, more meat – poultry, this time

By Leave a Comment

Constant readers: Fresh from the journal Emerging Infectious Diseases — posted AOP (electronic publication/ahead of print) this afternoon — comes more news of MRSA ST 398, the “pig strain,” in food animals. This time, it’s chickens, in Belgium.

The authors (from Ghent University and the Veterinary and Agrochemical Research Center in Brussels) took swabs from living chickens — laying hens and broilers — from 24 farms, 50 layers and 75 broilers total; one broiler-raising farm was sampled twice. They found no MRSA in the layers, which is important for reasons I’ll get to in a moment, and ST 398 in 8 broilers. From each chicken, they took two samples, nasal and cloacal, and in the 8 positive chickens, they got 15 MRSA isolations; one cloacal swab was negative. Of the positive chickens, several (I deduce three, but the math is a bit cloudy) were spread across the two visits to the farm that was sampled twice. Since chicken farms are depopulated between batches — yes, just what it sounds like, farms sell/kill all the birds and clean the place — that finding suggests that MRSA is persisting in the environment on that farm.

Important point: This strain was ST 398, which we here have been calling the pig strain from many previous findings, most of them in pigs. However, ST 398 is an identification using a particular technique called MLST (multi-locus sequence typing), which is used for this strain because the standard typing method, PFGE (pulsed-field gel electrophoresis), did not return a readable result when the strain was first identfied back in 2004. (Trivia: That’s why the initial reports of this strain called it NT, for “nontypeable.”) It’s becoming increasingly clear, though, that ST 398 is actually a category, not a single strain. And within that category, today’s research is a new find: a strain with the unusual spa type t1456, which has only been found 10 times in the past three years, in Germany and the Netherlands, not in Belgium. The author suggest that this particular strain may be adapting to poultry in the same manner that the ST 398 we have been talking about (different spa type — sorry, I will have to look it up) has adapted to pigs.

So, as before: Why do we care? We care for two reasons: First, because since this strain is in a food animal, the possibility exists that it could contaminate the chickens’ meat during slaughter and pass to humans. As has happened with some ST 398, the humans could be only colonized, and not become ill. But, second, any increase in colonization is a bad thing: The more strains out there, the greater the chance that they will exchange virulence and resistance factors and become something unpredictable.

Now, about those layers, here’s an interesting factor that the authors call out in their paper: Layers, unlike broilers, do not receive antibiotics. The layers did not carry MRSA. The broilers did. It’s a pretty potent argument, in case anyone needed convincing, of the effect of the selective pressure that antibiotic use in food animals exerts on these strains.

The site is: Persoons D, Van Hoorebeke S, Hermans K, Butaye P, de Kruif A, Haesebrouck F, et al. Methicillin-resistant Staphylococcus aureus in poultry. Emerg Infect Dis. 2009 Mar; [Epub ahead of print] DOI: 10.3201/eid1503.080696