MRSA news from Europe - Society for General Microbiology

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)

A little sardonic (botanical) humor - "39 more 'oops' "...

Courtesy of ReACT, a Web-based international coalition on antibiotic resistance.

Back to bad news tomorrow.

Non-pharm prevention alternative for MRSA skin infections

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.

Studies: gator blood, sudden infant death syndrome

I blogged earlier on new research that alligator blood may contain potent antimicrobial compounds. Now the Miami Herald has done a nice long story that thoughtfully explores the possibilities and limitations of that research. (Hat tip to KSJ ScienceTracker for noting the story.)

And via the BBC, here is a report that British researchers believe some vases of Sudden Infant Death Syndrome (which the English call " sudden unexpected death in infancy (SUDI)") may be due to undetected bacterial infections.

The researchers took samples from 470 babies who had died suddenly, and tested them for the presence of bacteria, particularly those capable of causing illness, such as Staphylococcus aureus or E. coli.
In some cases, the cause of death was known to be a bacterial infection, or completely unrelated to infection, for example a heart defect or accident. The rest were entirely unexplained.
Among those known to have died from a bacterial infection, 24% of the bacteria found were potentially harmful, compared with only 11% of those found in the non-infection group.
However, among the "unexplained" group, the figure was 19%, with 16% of bacteria found in this group identified as Staphylococcus, compared with 9% in the non-infection group. (Emphasis added.)

The authors theorize that toxins produced by staph could interfere with breathing or affect the nervous system. The paper, just published by The Lancet, is here and a Lancet-produced podcast (.mp3) is here.

Natural remedies - upsides and downsides

For obvious reasons there is a lot of interest in finding new sources for antimicrobial compounds that work against MRSA, and in finding non-drug remedies as well. There's been a small upsurge in reports of such research recently, which may be coincidence or may simply be due to the timing of certain scientific meetings.

Notably there was the report of "four or five super-active peptides" found in the blood of alligators and reported at the American Chemical Society's annual meeting a few weeks ago (first author Lancia Darville. Louisiana State University; Science News' take on the story is here), and another report at the same meeting of antimicrobial compounds in clay (authors Lynda Williams and Shelley Haydel of Arizona State University; press release here).

And just a few days ago, the journal Clinical Infectious Diseases posted ahead-of-print a study from the Netherlands on a "medical-grade honey" named Revamil that reduced skin colonization by resistant bacteria 100-fold.

That study's authors raise a red flag: that while honey has an antibacterial reputation that reaches back into prehistory, most investigations of honey as an antimicrobial have tripped up on the lack of product standardization, with batches from different areas, or even the same area at different times, showing significant variations in antibacterial activity. (Standardization of active ingredient is a long-standing problem for herbal remedies as well; regulatory authorities in Europe, where herbal preparations are more mainstream, are far ahead of the US on tackling this.)

It's important to remember that, naturally-sourced or not, antimicrobials are antimicrobials and must be handled with care, or they may invoke the sort of unintended consequences that brought us resistant organisms in the first place. For an excellent example of this, see a little-noticed paper from Irish researchers published last year in the the Journal of Antimicrobial Chemistry. That group found problems with the well-researched natural antimicrobial tea tree oil (Melaleuca alternifolia), which is commonly used in "natural" toiletries and cleaning products (and which I have in my own medicine cabinet). When tea tree oil was applied to bacterial colonies at a lower-than-lethal dose, the surviving bacteria developed resistance not only against the oil's active ingredient, but also against a range of antibiotics including vancomycin.