Maryn McKenna

Journalist and Author

Catching up to MRSA news (not about me)

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Constant readers: I’m looking forward to having the breathing space to get back to in-depth blogging. Meanwhile, though, news is zipping by — so here’s a quick list of recent things worth reading.

“Cows on Drugs” — a superb history of the 30-year-old fight to get unnecessary antibiotics out of food animals. Note, written by a former commissioner of the Food and Drug Administration, not exactly a wild-eyed radical:

More than 30 years ago, when I was commissioner of the United States Food and Drug Administration, we proposed eliminating the use of penicillin and two other antibiotics to promote growth in animals raised for food. When agribusiness interests persuaded Congress not to approve that regulation, we saw firsthand how strong politics can trump wise policy and good science.Even back then, this nontherapeutic use of antibiotics was being linked to the evolution of antibiotic resistance in bacteria that infect humans. To the leading microbiologists on the F.D.A.’s advisory committee, it was clearly a very bad idea to fatten animals with the same antibiotics used to treat people. But the American Meat Institute and its lobbyists in Washington blocked the F.D.A. proposal.

 Antibiotic resistance in your kitchen, playroom, car... — After years of begging from health advocates, the FDA and EPA are taking a second look at the chemical compound triclosan, an antibacterial that is put into, well, almost anything you can name: soaps, hand sanitizers, cutting boards, toys. Triclosan is suspected of interfering with hormone regulation in the body, and also increases resistance in organisms in our environment. (When I ask you to use hand sanitizers that contain only alcohol or salts, not antibacterials, triclosan is one of the things I’m thinking of.) The FDA will report its findings in a year. I’d rather see it happen sooner, but it’s a great move.

No progress on hospital-acquired infections — The Agency for Healthcare Research and Quality, part of the Department of Health and Human Services, has published its 2009 National Healthcare Quality Report. The news is not good. To quote the agency’s own language: “Very little progress has been made on eliminating health care-associated infections.” This is all hospital-acquired infections, not just MRSA, but MRSA is a leading organism. The ugly details:

  • Post-operative bloodstream infections up 8%
  • Post-operative catheter-associated urinary-tract infections up 3.6%
  • “Selected infections due to medical care” up by 1.6%
  • Bloodstream infections as a result of central lines unchanged.

(NB, three professional organizations — the Infectious Diseases Society of America, the Society for Healthcare Epidemiology of America, and the Association for Professionals in Infection Control — put out a statement in response to this report saying it “presents an outdated and incomplete picture on healthcare-associated infections (HAIs) in our healthcare system.” The gist of the statement seems to be that they’ve got better numbers coming… soon. When there’s actual data, I’ll let you know.)

News round-up!

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As promised, lots to catch up on — so here’s a quick round-up of some great reading that I have been stashing and that you may have missed in the past few weeks.

BBC News: Disinfectants may train bacteria to resist antibiotics
The BBC Health page (bookmark it!) translates a paper from the journal Microbiology on Pseudomonas aeruginosa’s newly recognized ability to pump the active ingredient in disinfectants out of its cells — and then to apply that same ability to the antibiotic Ciprofloxacin, even when it has never been exposed to Cipro before. Money quote: “... Residue from incorrectly diluted disinfectants left on hospital surfaces could promote the growth of antibiotic-resistant bacteria.”

Associated Press:  Solution to killer superbug found in Norway
In the latest installment in a 6-month series, AP writers Martha Mendoza and Margie Mason examine Norway’s success in forcing down rates of hospital MRSA. chiefly by extremely strict control of antibiotics dispensed in hospitals. I have some disagreements with this story; I don’t think they account for how much easier it is to do antibiotic stewardship, as it’s called, in a single-payer health system such as Norway or their second example, England, compared to the extremely complex US system. But I’m very glad to see the AP (and the Nieman Foundation at Harvard, where Mason was a fellow) support public exploration of antibiotic resistance, which I obviously feel gets insufficient attention. (Stay tuned for SUPERBUG’s discussion of one US stewardship program that has worked and may be replicable.)

Time: Should weight factor into antibiotic dosage?
Time.com looks at a provocative new paper in the Lancet that questions whether standard prescribed dosing of antibiotics isn’t really a form of inappropriate use. Money quote: “Dosage according to body mass is standard in anesthetics, pediatrics, oncology and other fields, [but] when it comes to antibiotics and antimicrobials the dosing guidelines are too broad… and may undermine a medications efficacy. …In the face of both widespread obesity and the increasing prevalence of antibiotic-resistance, tailoring dosage for optimal results is increasingly important.“

And finally, new today:
Science Daily: Bacteria Are More Capable of Complex Decision-Making Than Thought
University of Tennessee researchers explore the ability of a bacterium (the soil bacterium Azospirillum brasilense) to sense changes in its environment, process that information and make surprisingly complex decisions in response.

MRSA news from Europe – Society for General Microbiology

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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)

Sign of the times: Taking your own cleaning materials to the hospital

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There are several new and important reports out on hospital-acquired infections (HAIs) that I hope to get to this week, but I spotted something today that I just had to highlight first:

Constant readers may know that I’ve done a lot of reporting in the developing world. In parts of Asia and Africa, it is assumed that patients or their families bring food to the hospital. People do not trust the hospitals to feed them, with good reason: Hospitals can’t afford it. Provision of food in the hospital, which we take for granted, is not part of the health-care culture. (In particularly poor countries, the family may feed not only the patient, but the health care workers taking care of the patient as well.)

Here now is an industrialized-world version of that developing-world practice. A company in England (which, as we’ve discussed, has ferocious rates of hospital MRSA and C. difficile) has begun marketing the PatientPak, the “world’s first personal anti-superbug kit.” It’s a $28 sample-sized collection of antimicrobial hair and body wash, hand wipes, hand sanitizer and a germ-killing spray for sheets and cubicle curtains, along with lip balm, bar soap, and a disposable nail brush and pen.

It’s entirely possible that using products like this might protect a patient from some hospital-acquired infections; the company suggests that a patient use the wipes and the hand spray when going to and from the bathroom or after touching any surfaces. But the difficult reality, of course, is that most hospital-acquired infections are not the patient’s fault: They are due to infection-control breaches by hospital staff, something over which a patient — with antimicrobial wipes or without — has little control.

This company will probably sell quite a few of these kits — and I don’t know that I can criticize them for doing so. If one of my family members was being admitted to hospital, I might well send something like this with them. But what a sad commentary on our own health-care culture that any of us would consider this necessary.

Non-pharm prevention alternative for MRSA skin infections

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Longtime reader and botanical-medicine expert Robyn spotted this new story and study this morning and pointed it out in the comments to a previous post. It’s about a product, but it’s a product with science to back it, so under my rules regarding commercial products, I am moving it up to post status. (Robyn didn’t say, but given the internals of her post I assume, that she has no commercial interest in this. Right, Robyn?)

The product under investigation is an over-the-counter cream called StaphASeptic that contains the natural antimicrobials tea tree (Melaleuca alternifolia) oil and white thyme (Thymus vulgaris — the “white” refers to the preparation not the species) oil, along with the commercial antiseptic benzethonium chloride. That product’s effect on isolates of CA-MRSA was compared against two common OTC first aid creams, one containing the topical antibiotic polymyxin B and the other containing both polymyxin B and the topical antibiotic neomycin.

The authors found that the botanical-containing cream did a better job of killing CA-MRSA in a time-kill analysis, finding specifically that it went on killing longer — up to 24 hours — than the other two creams. The assumption obviously is that this non-antibiotic cream would do a better job of protecting superficial wounds and scrapes from MRSA infection than the antibiotic-containing ones, while presumably not promoting resistance.

But the important question, which Robyn raises, is whether the essential oils are not in fact acting as natural antibiotics, possibly synergistically. Let’s remember that the majority of antibiotics — including, for instance MRSA drug-of-last-resort vancomycin, and its replacement daptomycin — were initially isolated from natural substances (fungi, in both those cases). Overall, however, botanical products receive much less research attention that pharmaceuticals, so their action and their therapeutic potential remain unexplored.

The cite is: Bearden, DT, Allen GP and Christensen JM. Comparative in vitro activities of topical wound care products against community-associated methicillin-resistant Staphylococcus aureus. Journal of Antimicrobial Chemotherapy (2008) 62, 769–772. NB: The research was supported by an unrestricted grant from StaphASeptic ‘s manufacturers, Tec Laboratories Inc., and JM Christensen, of the Oregon State University College of Pharmacy, disclosed a consultant relationship with Tec.

Isolation: Doesn’t work if healthcare workers contaminate themselves afterward

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In the new Emerging Infectious Diseases, there is a small but very smart study that ought to get wider play. It was done by a PhD candidate at University of North Carolina, Chapel Hill named Lisa Casanova, with the help of faculty and the local health department.

Background: In certain highly infectious environments — including in-hospital isolation — healthcare workers wear what is usually known as “personal protective equipment” or PPE. PPE generally includes gloves, gown and an eye shield, goggles or face-splash guard (also called “barrier precautions”) as well as a mask or a respirator (“respiratory protection”). PPE protects the healthcare worker while he or she is in the patient’s presence, but it poses a problem when the worker leaves that environment, because the PPE is likely to be carrying the disease organism on its surface. If the worker doesn’t doff the PPE very carefully, he or she might contaminate himself/herself and become infected or colonized, or spread the organism further in the healthcare environment.

This accidental contamination was a significant problem in the 2003 SARS epidemic — so after SARS was over, the Centers for Disease Control and Prevention came up with a recommended procedure for taking off PPE (on this page, half-way down). Casanova decided to test how well the protocol actually works.

Answer: Not so much. She had 10 volunteers (men and women, left- and right-handed) dress in PPE, contaminated the equipment in certain spots (“front shoulder of gown, back shoulder of gown, right side of N95 respirator, upper right front of goggles, and palm of dominant hand”) with a benign virus, had the volunteers take off their PPE, and then tested them for the virus’s presence. Results:

Transfer of virus to both hands, the initially uncontaminated glove on the nondominant hand, and the scrub shirt and pants worn underneath the PPE was observed in most volunteers.

Casanova recommends changes: additional PPE; different PPE and doffing protocols, such as are used in surgical suites; or PPE impregnated with antimicrobials. (#1 and #3 of course would be more costly; #2 would require procedural change but not necessarily additional garments).

She also raises a vital ongoing issue for MRSA infection control: that healthcare workers may not be punctilious about hand hygiene because they believe that gloves are adequate protection. Only, as this study demonstrates, they are not:

This study also indicates the need for continued emphasis on hand hygiene. A barrier to improving hand hygiene compliance rates is the belief that gloves make hand hygiene unnecessary (14). This is contradicted by our study and others showing that organisms can spread from gloves to hands after glove removal (15). Even if double gloving is incorporated into protocols for PPE use, it is not a substitute for proper hand hygiene.

The cite is: Casanova L, Alfano-Sobsey E, Rutala WA, Weber DJ, Sobsey M. Virus transfer from personal protective equipment to healthcare employees’ skin and clothing. Emerg Infect Dis. 2008 Aug; [Epub ahead of print]