Maryn McKenna

Journalist and Author

Non-medical use of antibiotics: A whole new problem with ethanol

By Leave a Comment

Constant readers, we’ve talked frequently about the emerging recognition that the enormous use of antibiotics in agriculture is fueling the development of resistance, both directly in the case of specific organisms such as MRSA ST-398, and indirectly in that it pushes the evolution of resistance factors that bacteria then trade amongst themselves. (For a superb overview of the antibiotics/agriculture problem, see this article in the June issue of the Johns Hopkins (University) Magazine. Hopkins is the home of the Center for a Livable Future, which is doing excellent research on this issue.)

And we’ve also talked about the related issue of antibiotic residues elsewhere in the environment, in sewage and wastewater supplies.

But here’s a whole new peril: Antibiotic resistance generated by ethanol production, that vast corn-based industry that has been pitched as a homegrown biofuel alternative to foreign oil.

Food-policy blogger (and farmer and chef) Tom Philpott has been doggedly following this story for more than a year at Grist. And in a study published last month the Institute for Agriculture and Trade Policy brings some important numbers-based analysis. The gist of the problem is this:

  • Ethanol production uses yeast to convert corn starches into alcohol
  • Bacterial contamination, usually by lactobacilli, can hijack the process and covert the starches to unusable lactic acid instead
  • To prevent that from happening, ethanol producers dose their corn mash with antibiotics
  • Because contamination is frequent and persistent, producers use increasing amounts of antibiotics to overcome bacteria that have become resistant
  • After ethanol is extracted, the mash residue remains tainted with those resistant bacteria and with antibiotics — including penicillin, erythromycin and streptogramin (an analog of the human antibiotic Synercid)
  • The dried mash residue is sold to farmers as livestock feed, exposing livestock to resistant bacteria and dosing them with unsuspected additional antibiotics as well.

If there is any good news in this, it is that (according to the IATP), some of the faltering ethanol industry is aware of the problem and working on it, with about 45% of plants now working on non-antibiotic alternatives. The bad news is that 55% — more than 90 of the 170 ethanol facilities in the United States — are not.

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 and pets

By Leave a Comment

It’s been a while since we’ve focused on the presence of MRSA strains in pets, and the complications that can cause for the pets’ human owners/custodians/companions (or, in the view of my own two cats, abject servants. No, I will not post their pictures. I have some shreds of pride).

The problem with MRSA and pets is not the same as the problem of MRSA ST398 in food animals. Rather, pets tend to carry human strains, passed to them by their owners. The carriage is usually asymptomatic, but not always; there are cases in the medical literature of cats and dogs suffering serious skin and soft-tissue infections from community-strain MRSA, usually USA300. But the emerging consensus seems to be that pets carry the bug transiently — not long, but long enough to reinfect the person who passed the bacterium to the pet in the first place. (This can be, but is not always, the source of recurrent infections in humans: The human takes antibiotics and recovers, but the animal holds onto the bug long enough to pass it back to the now-clear human.)

For anyone who needs to go deeper on this, the current issue of Lancet Infectious Diseases has a good overview of the problem that community MRSA strains pose to pets and their humans. There’s a thorough review of the major papers:

  • Cefai, 1994: hospital outbreaks traced to two nurses and through them to their dog
  • Simoons-Smit, 2000: household epidemic of three humans, one cat, one dog
  • Manian, 2003; dog is source for owner’s recurrences
  • Vitale, 2006: owner is (apparently) source of cat’s MRSA.

(This is a good place to say that this entire history, including personal stories of human and animal infection, is covered in a chapter of SUPERBUG. Publication date coming soon!)

The Lancet paper incorporates reminders of some powerful and troubling trends. As with MRSA ST398, one thing can distinguish MRSA that has been in an animal is a resistance pattern that is slightly different from what we expect but that has arisen because the animals receive different drugs. In the case of pigs and ST398, the intriguing marker is tetracycline resistance; humans don’t usually get tetracycline for MRSA, but pigs do. In the case of companion animals, it tends to be fluoroquinolone resistance; pets are more likely to get that class of drugs for a skin/soft-tissue infection. But, the authors caution, that may mean that pets serve as a breeding ground for multi-drug resistant MRSA, with their fluoroquinolone treatment adding another resistance factor into the bug’s already potent arsenal.

The authors also remind us that MRSA can come from animals much more directly than through silent carriage: that is, in a bite. Both dog and cat bites have been found infected with MRSA, due to bacterial contamination of the wound either from the pet or from colonization on the human’s skin.

The cite is: Oehler RL et al. Bite-related and septic syndromes caused by cats and dogs. The Lancet Infectious Diseases, 9(7):439 – 447, July 2009. doi:10.1016/S1473-3099(09)70110-0.

H1N1 flu and swine surveillance – more relevance for MRSA

By Leave a Comment

Constant readers, you probably know that yesterday the World Health Organization declared the first flu pandemic in 41 years. I want to point out for you a side issue in the H1N1 story that has great relevance for MRSA, especially ST398.

As described in this article I wrote last night for CIDRAP, three medical journal articles have now pointed out that the virus, or its major components, could have been recognized in swine months to years ago. We missed it, though, because there is so little regular surveillance in pigs for diseases of potential importance to humans. As the authors of the most recent article, in Nature, said yesterday: “Despite widespread influenza surveillance in humans, the lack of systematic swine surveillance allowed for the undetected persistence and evolution of this potentially pandemic strain for many years.”

This is important for our purposes because we know that we are in the same situation with MRSA ST398: The strain was first spotted in France, and has been a particular research project in the Netherlands, but has been found pretty much wherever researchers have looked for it, throughout the European Union, in Canada, and most recently in the United States. All told, though, the scientists concerned with it are still a small community; there is no broad surveillance looking for this bug.

And that’s a problem, for MRSA, for influenza, and for any number of other potentially zonotic diseases: We cannot anticipate the movement of pathogens from animals to humans if we don’t know what’s in the animals to start with. That’s the argument behind the “One Health” movement, which has been arguing for several years now for including veterinary concerns in human health planning. (The human health side would probably say that the animal health side just wants more money. This is also true, which does not make it unimportant.)

To understand the need to look at animal health in order to forecast threats to human health, you can’t do better than the map I’ve inserted above (because Blogger, annoyingly, won’t let me put it below). It has appeared in various forms in various publications for about 10 years but originates I think from the IOM’s Emerging and Reemerging Diseases report in the early 90s. (This iteration comes from the One Health Initiative website.) It depicts the movement of new diseases from animals to humans over about 30 years. It’s up-to-date through SARS and through the 2003-05 movement of H5N1 avian flu around the world. I’m sure H1N1 will be added soon. How many of those outbreaks could we have shortcircuited if we had been warned of their threat in good time?

MRSA in pig-farm workers – very high rates

By Leave a Comment

Let’s go back for a moment to what I think of as the “third epidemic” of MRSA: ST398 and the other strains that reside in animals and cross to humans. (In my personal taxonomy, the first and second epidemics are hospital-acquired and community-associated.)

Via Emerging Infectious Diseases, the open-access journal published by the CDC (Do I have to keep telling you to read it? It’s free. It’s good. Your tax dollars pay for it.), comes a report of surveillance for MRSA colonization of pig-farm workers, conducted in Belgium by researchers from Erasmus Hospital of the Free University of Brussels, and the Veterinary and Agrochemical Research Centre of Brussels. The group persuaded 127 farm workers on 49 farms to be tested for colonization, or asymptomatic carriage, of MRSA; at the same time, they tested 30 randomly selected pigs on each farm.

They found very high rates of colonization, higher than have been found in patients in hospitals or residents of nursing homes: 38% of the farm workers carried MRSA ST398, the pig strain (plus, an additional 17% carried various strains of MSSA, drug-susceptible staph). There was a clear association between colonized farmers and colonized pigs: Out of 1500 pigs sampled, 44% carried ST398 — and half of the workers on farms with colonized pigs were colonized also, compared to only 3% of workers on farms where pigs did not carry the bug.

In a bit of good news, the researchers found only one farm worker who had suffered any MRSA disease from ST398, a man with a lesion on his hand. There was no invasive disease, though ST398 has been associated in the past with pneumonia and endocarditis.

Workers were more likely to acquire the bug if they had regular contact with pigs, dogs or horses, which makes intuitive sense. But in an odd finding, their odds of acquiring ST398 did not go down if they wore protective clothing — which is to say, aprons, gloves and masks did not protect them from picking up the bug, leading the researchers to wonder whether airborne spread or contaminated surfaces are playing a role in transmission.

So what does this mean? The lack of invasive disease in this population must be good news; and it’s consistent with a number of papers that have reported low rates of disease from ST398 even when colonization is present. But to me, the high rate of colonization must be bad news. The more of this bug there is (and every researcher who looks for it seems to find it), the more chance there is of the bug adapting in an unpredictable — potentialy more resistant, potentially more virulent — way. If that did happen, it could well go undetected for a while — because as swine flu has been teaching us, disease surveillance in animals is patchy at best, and new pathogens can and do arise and ciruclate for years before being detected.

For more on the paucity of surveillance in animals, see my CIDRAP colleague Lisa Schnirring’s story here. For a complete archive of posts on “pig MRSA” ST398, go here.

The cite is: Denis O, Suetens C, Hallin M, Catry B, Ramboer I, Dispas M, et al. Methicillin-resistant Staphylococcus aureus ST398 in swine farm personnel, Belgium. Emerg Infect Dis. 2009 Jul; [Epub ahead of print] DOI: 10.3201/eid1507.080652.

MRSA in the House of Lords — the silly, the serious

By Leave a Comment

Thanks to constant reader Pat Gardiner, we have the transcript of the UK House of Lords discussion on community MRSA, called there PVL-MRSA after the toxin. (Go to the linked page, and click down to the time-mark 3.16 pm.) It’s encouraging to see some members of a government taking MRSA seriously. The members are asking for

  • better surveillance
  • better infection control
  • consideration of MRSA as a notifiable disease
  • and promotion of both vaccine research and point-of-care diagnostics.

Hear, hear to Baroness Masham of Ilton for bringing it up.

To get to that discussion, though, you’ll have to click down through some silliness (the ghost of Monty Python is never far from the British government, is it?): a discussion at time-stamp 3.07 p.m. of whether a House of Lords restaurant can afford to serve British bacon, rather than Dutch bacon, given that British bacon is almost twice as expensive and Dutch pigs are associated with MRSA ST398:

Lord Hoyle: My Lords, I thank the noble Lord for that reply, although there is more than a whiff of hypocrisy about it. After all, I and many others on all sides of the House have argued that it should not be a matter of price. We have urged the British consumer to buy British bacon because of the higher welfare standards that are applied in this country. Will the noble Lord also take into account the presence in Dutch bacon of a deadly form of MRSA, ST398, which can cause skin infection, heart trouble and pneumonia? Is he not putting people in this country at risk, particularly as the strain has passed from animals to humans? Indeed, when Dutch farmers go into hospital, they go into isolation. Why is he putting the British consumer and those who buy bacon in this House at risk in this way?

The discussion quickly devolves into foolishness about British Tomato Week — but if you read carefully, you’ll see that behind the silliness, there are serious issues at stake: animal welfare, farming standards, truth in labeling (the Lord Bishop of Exeter advances the very newsworthy claim that pork imported from other countries is subsequently labeled “British” only because it is packaged in the UK) and movement of zoonotic pathogens across national borders thanks to globalized trade.

Sadly, the leader of the discussion — the Chairman of Committees, AKA Lord Brabazon of Tara (no, really) — appears not to have been keeping up with the news, since he notes of ST398:

As far as MRSA is concerned, I read the article in, I think, the Daily Express a couple of weeks ago. I do not think that it has been followed up by anybody else.

Apparently the Lord’s staff have not been keeping up, since MRSA in pigs in the EU has been covered by the Daily Mail, the Independent, comprehensively by the Soil Association, and by, ahem, us.

ST398 found again — in Italy

By Leave a Comment

There’s a letter in the upcoming issue of Emerging Infectious Diseases (hat tip Pat Gardiner) alerting the medical community that “pig MRSA” ST398 has been found in Italy, adding t the steadily enlarging list of countries where this strain has been identified.

(NB: Because most of these surveys are one-offs, we don’t yet know whether ST398 is truly expanding its range, or has always been there, but no one looked until now.)

Angelo Pan and colleagues of the Cremona Hospital and other institutions report that a pig-farm worker was discovered to have a severe pyomyositis (abscess buried in muscle):

The case-patient was a 58-year-old man admitted to a surgical department in Cremona, Italy, on July 30, 2007, because of a 1-week history of fever and intense pain in his right buttock. He worked on a pig farm, was obese, consumed high volumes of wine (1.5 L/day), was taking medication for hypertension, and had not had recent (<5 years) contact with the healthcare system. At the time of hospital admission, he was moderately ill, oriented, and cooperative. His right buttock was extremely painful. He reported neither recent trauma nor anything that would explain infection. ...
Based on clinical and magnetic resonance imaging data, the diagnosis was cellulitis, pyomyositis, and pelvic multiloculated abscess of the buttock. A needle aspiration of the abscess, guided by computed tomography, was performed. Because of persistent fever (38.5°C), oral ciprofloxacin was added to the patient’s treatment regimen on day 3. Blood and abscess cultures yielded MRSA that was sensitive to glycopeptides, rifampin, linezolid, gentamicin, and mupirocin and resistant to co-trimoxazole, macrolides, clindamycin, and fluoroquinolones. After treatment was switched to vancomycin plus rifampin, the patient’s general condition improved; he was discharged from the hospital after 24 days.

An investigation was launched, and the results were intriguing:

Two fellow workers were colonized with S. aureus, 1 with methicillin-sensitive S. aureus (MSSA) and the other with MRSA. The pig farm, a farrow-to-finish production farm with 3,500 pigs, was screened for MRSA … Dust swabs were taken from 5 areas of the farm; 7 MRSA isolates were detected.
The isolate from the patient belonged to spa type t899, was ST398, carried an SCCmec type IVa cassette, and was PVL negative. The isolate from the MRSA-colonized worker was a t108 strain carrying SCCmec type V. The isolate from the MSSA-colonized worker was identified as t899. The dust swabs yielded 7 isolates: 2 belonged to t899 and carried SCCmec IVa; 5 belonged to t108 and carryied SCCmec V. The isolates obtained from the patient, farrowing area 7, and gestation area 1 were indistinguishable (i.e., same spa type, SCCmec type, and ST profile; Table), thus confirming the animal origin of transmission.

So, we have:

  • A high rate of carriage on the farm (3 of 4 workers with ST398, either MR or MS)
  • A strain-type that is both MRSA and MSSA, suggesting that in its drug-sensitive state it can acquire resistance factors rather easily
  • A PVL-negative strain that nevertheless causes invasive disease requiring more than 3 weeks hospitalization

None of these are good news.

The authors very sensibly call for more public-health attention to this strain, which — we have contended before — is long overdue:

…attention should be given to the emergence of MRSA strains among animals, and continuous surveillance in humans should monitor the extent of disease from MRSA ST398, especially in areas of intensive animal farming. Collaboration between infectious disease specialists, microbiologists, and epidemiologists, on both the human and the veterinary sides, should be strengthened and readied for appropriate action whenever complex, zoonotic, public health issues occur.

The cite is: Pan A, Battisti A, Zoncada A, Bernieri F, Boldini M, Franco A, et al. Community-acquired methicillin-resistant Staphylococcus aureus ST398 infection, Italy [letter]. Emerg Infect Dis [serial on the Internet]. 2009 May. DOI: 10.3201/eid1505.081417

Appearing today on The Ethicurean

By Leave a Comment

Constant readers, I want to let you know that the terrific food policy blog The Ethicurean (motto: “Chew the right thing“) very kindly had me over to do a Q&A on MRSA in meat. Please take a look and let them have some clicks: They are smart people thoughtfully elucidating a difficult subject, and worth following.

(And I would say that even if they hadn’t called me the “Superbug supersource,” honest.)

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

More news on ST398, “pig MRSA,” in Europe

By Leave a Comment

Two new papers have been posted ahead-of-print to the website of Emerging Infectious Diseases, the free journal published monthly by the CDC. (It’s a great journal. Just go.)

One, from the Austrian National Reference Center for Nosocomial Infections, reports that out of 1,098 isolates from infected or colonized hospital patients collected between 2006 and 2008, 21 were ST398, the “pig strain” that we have talked so much about here. Of the 21, 15 were colonized and 5 had actual infections (one person lost to followup, apparently); of the 5 infections, 4 were minor, and one was a very serious infection in a knee replacement in a 64-year-old farmer.

In a separate piece of math that is not fully explained, the researchers note that the prevalence of ST398 in Austria has risen to 2.5% of MRSA isolations, from 1.3% at the end of 2006 — close to double, and especially rapid given that Austria’s very first ST398 sample was found during 2006.

The second paper is much more complex; it deals with the prevalence of multiple MRSA strains in the cross-border region where Germany, Belgium and the Netherlands bump up. (Apparently EU bureaucracy calls an area like this a “Euregio.” Ah, jargon. This is the EMR, the Euregio Meuse-Rhin.) The concern here is that MRSA prevalence is very different in different EU countries; in the Netherlands, which has an active surveillance “search and destroy” policy in its hospitals, MRSA represents only 0.6% of all staph — but the rates are 13.8% in Germany and 23.6% in Belgium, which either do not do active surveillance or began to much more recently. So as people move freely across borders, from a high-prevalence area to a low-prevalence one, they could bring a resistant bug with them that then could find a foothold because there is an open ecological niche.

This study analyzed 257 MRSA isolates from hospitals in the border region that were collected between July 2005 and April 2006: 44 from Belgium, 92 from Germany, and 121 from the Netherlands. Of the Dutch isolates, according to typing, 12 (10%) were ST398. These were all from patients who were identified as colonized when they checked into hospitals practicing “search and destroy”; none represented actual infections.

So, what does this tell us? A couple of things, I think. First, it documents the continued presence of ST398 in Europe; in other words, it wasn’t a blip and doesn’t appear to be going away. Second, it underlines both that you find it when you look for it, and also that it remains a small portion of the overall MRSA picture. But, we immediately have to add, it’s a small portion that wasn’t present at all just a few years ago.

And it should underline that what we need, and are not getting in this country or in Europe, is much more comprehensive surveillance and research to understand ST398’s place in MRSA’s natural history, so that we can understand where it is only an emerging disease, or truly an emerging threat.

The cites are:
Krziwanek K, Metz-Gercek S, Mittermayer H. Methicillin-resistant Staphylococcus aureus ST398 from human patients, Upper Austria. Emerg Infect Dis. 2009 May; [Epub ahead of print]
Deurenberg RH, Nulens E, Valvatne H, et al. Cross-border dissemination of methicillin-resistant Staphylococcus aureus, Euregio Meuse-Rhin region. Emerg Infect Dis. 2009 May; [Epub ahead of print]

British newspaper discovers ST398, says no UK cases – incorrect

By Leave a Comment

The UK’s Sunday Express takes note today of “pig MRSA” ST398 (full post archive here) in a story that is both somewhat alarmist and oddly incomplete, since it misses a piece of news that I told you about here last June.

The Express story raises the alarm over ST 398 in pigs in the Netherlands, colonizing farmers and causing human illnesses. There is nothing in it that we have not already discussed here many times, but it is nevertheless worth noting because it appears to be the first report on ST398 in a year in a major UK paper. (Credit for what I think is the first mention of ST398 in the Brit press goes to the Independent.)

But here’s what’s odd about the story: It says (italics mine),

A DEADLY new form of MRSA is believed to be spreading from farm animals to humans – already the bacteria has been found in hospitals abroad.
It is the first time the bug has spread in this way and experts believe excessive use of antibiotics in factory-farmed animals may be behind its development.
“Farm animal” MRSA, as it is known, can cause a raft of illnesses including skin infections, pneumonia, bone infections and endocarditis. …
The new MRSA bug, known as ST398, could reach hospitals in the UK, causing serious illness and death among vulnerable patients. (Byline Lucy Johnstone and Martyn Halle)

However as constant readers here already know, ST398 has already has been found in UK hospitals: in three unrelated patients — one adult and two newborns — in a Scottish hospital, none of whom had any relationship to pig-farming.

Credit for pushing the story of ST398 in the UK goes to the organic/sustainable farming group the Soil Association, who have aggressively monitored and lobbied for the extremely slow reveal of ST398 by the British government. As the issue now stands, the UK tested British pigs for ST398 colonization in 2008, but has not revealed the results. It has not yet tested retail meat in the UK, some of which is imported from the Netherlands, the location where the most ST398 has been found.

While that sounds like foot-dragging, it is still ahead of the US: Except for the study published in January by Tara Smith’s team at University of Iowa (paper here, my Scientific American story here), there has been no testing of pigs in the US, certainly none by government agencies.

(Hat-tip to Pat Gardiner for alerting me to the Sunday Express article.)

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.)

More on “pig MRSA” and the havoc it can do

By Leave a Comment

Folks, before I get to the SHEA abstracts, one more post on ST398 in humans, and a sad and difficult story. It is the first (to my knowledge) report of ST398 spreading into a nursing home, in the January 2009 issue of Eurosurveillance Weekly.

It was very thoroughly investigated, because it took place in the Netherlands, where by national policy there is active surveillance and testing — AKA “search and destroy” — for MRSA in health care facilities.

To me it is both an object lesson in the unpredictable spread of this newly recognized organism, and also an exploration of the deep human cost of combatting it.

The nursing home, in a town called Doorn, is described as a residence for “visually and intellectually disabled” people, and it sounds like a good place, made of 35 household-like units that hold 8 residents each, with a pretty high ration of staff to residents. One resident in one unit was an adult man (age not given) who was completely blind and significantly mentally disabled. Since 2004, he had been living with hidradenitis suppurativa, a condition of painful, recurring, weeping infections of the skin that can be caused by staph. Periodically, he was treated with a variety of antibiotics — tetracycline,erythromycin, flucloxacillin, trimethoprim/sulfamethoxazole, clindamycin, minocycline, rifampicin — but none of them seem to have made much difference to the infections. (Hidradenitis is an awful condition; there are times when the only treatment is skin grafts.)

In October 2007, the regular swabs taken of his infections suddenly showed not drug-sensitive staph, but MRSA. Confirmatory swabs showed that he was colonized with MRSA in the nose, throat and groin. After analyzing whom he might have been in contact with, the home identified 43 resident and staff at risk, swabbed them all, and found 2 other residents and 3 staff members colonized. That led to another round of swabbing, of 160 people, but no other cases of colonization were found.

So, just to recap, that is the index case, with MRSA infections and colonization in various places on his body, plus five others who were only colonized.

Sequencing/typing of the isolates found that all 6 were carrying ST398, falling into one of two spa types, t2383 and the more rare t011. None of the residents or staff had had any contact with livestock. They did have play/therapy animals at the residence — rabbits, chickens and goats — but they were checked and were all negative. The source was never found.

The five who were only colonized were given 5 days of decolonization therapy: mupirocin gel (Bactroban) in the nose and showers with chlorhexidine soap (Hibiclens). Afterward, they had to be proved negative on three successive nasal cultures; the paper does not say how far apart the cultures were. Until the third negative culture, staff had to stay home, and residents were banned from group activities. Underlining that: Physically or mentally disabled adults living in an enclosed, supportive society had to be isolated from it because they acquired this bug. Just think how difficult that must have been. The paper notes: “The outbreak caused commotion among the staff members, and they had a lot of practical questions as they were unfamiliar with MRSA and an MRSA-outbreak in particular. Furthermore, it turned out that the use of gloves, surgical masks and aprons during washing and clothing was perceived as threatening by the clients.“

The index case’s situation is even sadder. He was given a private bath and shower, and essentially restricted to there and to his private room. He had been in group day-care, but was switched to being minded by himself. His “social contacts with other residents who lived in other units was restricted to a minimum” — presumably he was not able to be fully secluded from the other members of his household. However, anyone who came into direct contact with him — for instance, to bathe and dress him — had to be on contact precautions: gloves, aprons and surgical masks. This went on for six months while his very refractory MRSA was treated with oral antibiotics and surgical incision and drainage of his abscesses; after six months, his symptoms had not resolved, but swabs of his wounds were MRSA-negative, and some of the isolation precautions were lifted.

Underlining: Someone blind and mentally disabled, presumably fairly secure in the enclosed, supportive society of the residential home, has to be restricted from his routine, from people who are probably his friends, and from all skin-to-skin contact, for half of a year.

Now, mind you: If you or I had a relative in that home, we might want them to do exactly what they did do. It is difficult to say how well the staff might have succeeded in getting mentally disabled residents to cooperate with, for instance, hand-washing.

But this is not the first case I have heard of where the cost of protecting a group from MRSA has fallen very, very hard on one individual. I am not going to argue with the Dutch policies, but in this case, I find their unintended consequences terribly sad.

“Sick as a pig” – from ST398

By Leave a Comment

Constant readers, I am at the annual meeting of the Society for Healthcare Epidemiology of America, where there is a lot of news about MRSA in hospitals. I hope to post on that over the next few days.

In the meantime, though, I want to pass on several pieces of news about ST398, the “pig strain” that we have talked so much about.

First, the Soil Association, the British organic/sustainable farming group that has done much work elucidating the spread of ST398 and making the link between that bug and antibiotic use on farms, has released an online documentary about ST398 called Sick as a Pig. You can watch it here, and here is the Soil Association’s press release:

…40% of Dutch pigs and up to 50% of Dutch pig farmers are now carrying the new strain, which is also spreading to the wider population. Although this type of MRSA was first detected in humans in the Netherlands as recently as 2003, it now causes almost one in three cases of MRSA treated in Dutch hospitals.
It is not yet known whether any British pigs are affected by the new strain of MRSA (called ST398) since the results of testing, which was required by the EU and carried out in 2008, have not been made public.
Several countries have already published the results of their own tests revealing significant levels of MRSA in national pig herds. The European Food Safety Authority has said that, ‘It seems likely that MRSA ST398 is widespread in the food animal population, most likely in all Member States with intensive animal production’.

Second, here is a paper from last fall that somehow slipped by me: in the CDC journal Emerging Infectious Diseases, a report of two cases of ST398 infection in men in Sweden. Neither had any contact with farming or animals.

The first patient, a previously healthy 36-year-old male physiotherapist, sought medical care in March 2006 for a small abscess in his axilla. Culture of the abscess grew MRSA. Presence of mecA gene was confirmed by PCR. During the next 2 months, furunculous [sic] developed twice, caused by the same strain. His youngest child, adopted from China, had been found to be MRSA positive (throat, perineum, and a small wound) a month earlier during routine screening for adopted children. During subsequent screening of the family, the older sister, adopted from South Korea, was also found positive (throat). Both parents were negative for MRSA at that time, which suggests that the father was newly infected when his abscess developed and that he had not acquired the strain abroad. Also, spa typing indicated that the children carried different strains from that of the father and from each other (t286, t1434). Subsequent screening of family members for MRSA on several occasions found only the father to be repeatedly positive.
The second patient, a 43-year-old male clerk, also previously healthy, sought medical attention during the summer of 2007 for a MRSA-infected elbow wound. Follow-up examination determined that he carried MRSA also in the perineum and in a chronic external otitis eczema. He was later hospitalized for a larger abscess that required surgical drainage. His family members reported no symptoms and were thus not screened for MRSA.

Of note, the men’s strain (ST398, t034) carried the two genes that express the toxin PVL, which is unusual in ST398, though characteristic of CA-MRSA USA300, the dominant community strain in the US. The role that PVL plays is very controversial: Some research groups believe it is responsible for the rapid tissue destruction that can accompany USA300 infection (in penumonia and some soft-tissue infections, for instance), while others vociferously disagree.

More MRSA in meat, in Austria

By Leave a Comment

There’s a new publication out that I haven’t been able to lay my hands on yet, except for the abstract. But here’s what I know: A group from the Austrian Agency for Health and Food Safety and two Austrian national reference laboratories have published a paper saying that ST 398, the “pig strain” of MRSA that we have been talking about here for a year now, has surfaced in Austria in environmental samples, in humans and also in food — presumably meat, but the abstract doesn’t say that.

The abstract in Wiener Klinischer Wochenshrift (Viennese weekly clinical review, if my college German is still with me) says:

…the emergence of ST398 is not just a Dutch problem, as reports on livestock colonization and human infections are appearing worldwide. In Austria, the ST398 lineage has been detected in dust samples from pig breeding facilities and in food samples. Since the first Austrian detection of this emerging lineage in 2006, 21 human isolates, partially associated with infections, have been observed. MRSA has to be regarded as a new emerging zoonotic agent and livestock may constitute a growing reservoir of the ST398 lineage.

The University of Minnesota (where, as you all know, I work part time for the excellent infectious-disease news site CIDRAP; please go) does not have electronic access to this journal, and ILL is slow. If anyone else has a copy and would like to share, I would be grateful.

The cite is: Springer, B. et al. Methicillin-resistant Staphylococcus aureus: A new zoonotic agent? Wien Klin Wochenschr. 2009 Feb;121(3-4):86-90. Abstract here.

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.

MRSA and animals — an elephant, this time.

By Leave a Comment

So, constant readers, I have wrestled another chapter to the ground — and thus have a few minutes’ breathing space to talk about a story that some of you have asked about privately. I’ve been wondering whether to post on this, because the entire episode is in the book, and I don’t want to scoop myself. But it’s so interesting, and so sad, that it seems worthwhile.

This episode happened a year ago, and was reported at a couple of medical meetings last fall, but it is in the news now because it was written up last week in the CDC’s Morbidity and Mortality Weekly Report or MMWR. (Which is the best-read magazine that you have never heard of. Hundreds of thousands of people all over the world read it every week for the latest in disease news. It’s free. Go, already.)

So, the brief synopsis: In late January 2008, the San Diego Zoo’s Wild Animal Park noticed that a baby African elephant, born in late November 2007, had broken out in pustules on her ear, neck, elbow and leg. Three of her caretakers had skin infections also. The zoo launched an investigation, assisted by a CDC Epidemic Intelligence Service officer who is assigned to California; they were concerned that the caretakers had unknowingly picked up a disease from the baby, who had been born early, was not thriving and was being intensively hand-reared by the zoo staff.

But in fact, it was more complicated than that. The pustules were MRSA, of course — but they were not ST 398, the animal strain that we have talked about so much here. Instead, they were USA300, the community-associated human strain that has zoomed to dominance all over the country. But there was no MRSA in the elephant herd, which the baby had not had contact with since late December. The reconstructed chain of transmission looked more like this: from an unknowingly colonized human to the baby elephant, who was medically fragile and had been isolated from her herd, and then from the elephant to the rest of the human “herd” who were caring for her. The strain involved was USA300, In the end, five human infections and three colonizations were laboratory-confirmed, and 15 other infections were suspected but not confirmed.

The humans recovered; most of their infections were so minor as to need no treatment, though three of them took oral antibiotics. The poor little elephant was not so lucky. She had multiple other illnesses, and she was euthanized on Feb. 4, 2008. The MRSA did not cause her death — by the time she died, the infection had resolved — but as one of the zoo staff told me, “It certainly didn’t help.”

So what does this tell us? Well, for zoo personnel, it tells them what to do for next time: More complete infection control especially around vulnerable animals. For microbiologists, it’s an expansion of MRSA’s range: No one had ever seen it in an elephant before.

For animal owners, it’s a warning and reminder. We’ve known for a while that community strains can transiently colonize pets, staying in the animal’s nose or elsewhere on the body just long enough to reinfect a human — in fact, an emerging piece of advice for physicians dealing with recurrent MRSA in families is, “Check the dogs and cats, too.”

And for the rest of us, it suggests, one more time, how extremely adaptive and inventive MRSA is, and that we should never underestimate its ability to surprise.