Image: Glenn Roberts
-
What a Plant Knows
How does a Venus flytrap know when to snap shut? Can it actually feel an insect’s tiny, spindly legs? And how do cherry blossoms know when to bloom? Can they...
Read More »
The nation's ongoing fungal meningitis outbreak has killed 30 and sickened 419 people so far, but the fungus responsible has never wrought such havoc before.
The fungus, Exserohilum rostratum, is a plant-eating generalist equipped with a spore-launching mechanism ideal for going airborne, is not an especially picky eater and, although it prefers grasses, will dine on many items—including humans.
But just how a pathogen typically associated with the great outdoors got into the three lots of injectable steroids prepared inside an admittedly filthy laboratory—and why only three lots—remains a puzzling mystery.
The errant fungus has been identified in lab samples from 52 of those affected and was similarly found growing in unopened vials of the steroid alleged to have caused the outbreak, according to the U.S. Centers for Disease Control and Prevention. A third recalled lot is still being tested. But E. rostratum is not a household name, even among mycologists.
Glenn Roberts, a retired medical mycologist, says that in his 40 years of experience at the Mayo Clinic in Rochester, Minn., he had seen only one case: a soft-tissue arm wound in an immunocompromised patient. He was shocked when he heard the identity of the pathogen in the epidemic that originated with the New England Compounding Center pharmacy in Framingham, Mass.
“I could hardly believe it because it’s just so uncommon,” he says.
And yet, outside in the air and on plants, E. rostratum is not so uncommon.
In press reports, it has been described as occurring "on grasses," but that is not the full story. The fungus, which seems to prefer tropical and subtropical environments, has turned up on a wide variety of plant species, says Kurt Leonard, an emeritus professor in the Department of Plant Pathology at the University of Minnesota who retired in 2001 from the U.S. Department of Agriculture's Cereal Disease Lab (then the Cereal Rust Lab).
Early in his career, Leonard untangled the taxonomic mess of similar-looking, but only distantly related, fungi with multicellular dark spores that were causing disease in grains such as corn. He named one new genus he had created—Exserohilum—for the prominent protuberances called hila (the belly buttons of the fungal and botanical world) on its spores.
The modus operandi of one species in this genus – E. rostratum -- was to infect a plant and in some cases precipitate tissue death. Plant defenses—which can include induced cell fortification, cell suicide, toxic chemicals, and defensive enzymes and proteins—typically were sufficient to keep the infection in check, but not strong enough to eliminate it. The payoff came when the plant died—the fungus was first in line to feed on its decaying remains. "I think it's just a general weak pathogen of plants," Leonard says, "something that can infect plants while alive and not really do much damage until the leaf senesces."
Leonard found E. rostratum on corn, sorghum and Johnsongrass fairly often, although it was not nearly as common as several more severe corn pathogens. It was an opportunist and would sometimes infect ears and stalks when insects drilled into the plant, creating a convenient landing pad of dying tissue for the fungus.
Most often the fungus shows up on grasses and other monocots—plants often distinguished by flower parts in threes and parallel leaf venation—such as pineapples, bananas and sugarcane, but it has also been found on non-monocots such as grapes and muskmelon. It's a fungus that is not, apparently, very picky about its food. "It's just a really common fungus in the environment that mostly lives on dead and dying plant tissue," Leonard says. There are many such others, and many of them can also occasionally infect animals or people.
See what we're tweeting about
10 Comments
Add CommentYour last paragraph is a zinger !
Reply | Report Abuse | Link to thisI'm sure that starting with natural products like the diosgenin from Mexican yams presents problems as far as obtaining complete sterility goes, but, really, are you sure the law allows using a non-sterile drug, in compounding an injectable finished product. That just seems so wrong. Why even bother using clean water?
Pasteur must be turning over in his grave.
Does anyone know a NIH source that shows what the rules allow? And if injectables are allowed to be non-sterile (can we say filthy?) what about oral blood pressure meds or antibiotics, or the thousands of other meds in pills or caps not to be injected.
How filthy are they allowed to be?
And how do we define non-sterile/filthy?
I have read they use that specific fungus , rostratum , in drug production to ramp up the production ?
Reply | Report Abuse | Link to thisIs E. rostratum killed in our digestive process-- or do we have to reconsider the hamburger-joints’ wilted lettuce with a more cautious eye? Is it an inhalable problem? Are hay-rides to be re-cataloged as extreme sports? Is picnicking in the park risky behavior?
Reply | Report Abuse | Link to thisironjustice: No, "they" don't. Please leave and take your anti-pharmaceutical conspiracy hypotheses with you.
Reply | Report Abuse | Link to thisR.d nyc: I would say that being careful of what you eat at hamburger joints is always a good idea. As for the other two...I don't think so, but maybe.
doug_pdq -- I think that the problem in this investigation was that compounding pharmacies are not regulated the same way as the rest of the pharmaceutical industry, and then this particular pharmacy was not even meeting minimum standards. It was especially filthy and careless with safety.
Reply | Report Abuse | Link to thisSee the following articles for more details on that angle
http://www.nytimes.com/2012/10/07/us/scant-drug-maker-oversight-in-meningitis-outbreak.html
and
http://www.nytimes.com/2012/10/27/health/fda-finds-unsanitary-conditions-at-new-england-compounding-center.html
R.d nyc -- This fungus is almost certainly harmless to people with healthy immune systems provided it is not injected into their spines. Of the few known human infections prior to this outbreak, most occurred in people with compromised immune systems or who had structural defects in their nose (a birth defect or a broken nose) that made it easier for the fungus to cause allergic sinusitis. Infections with this fungus of either variety are very rare. This is not a fungus most healthy people will ever need to worry about.
Bueno, parece ser que los hongos y aquéllos seres vivos que no son ni plantas ni animales tienen mucho que enseñar: "los colmillos"
Reply | Report Abuse | Link to thisIf you sterilize the final product, i don't see what difference it makes if the ingredients are sterile? When you mix up culture media the various ingredients are not sterile, but you do need to autoclave the media before stuff starts growing and producing unwanted products and changes to the media.
Reply | Report Abuse | Link to thisThanks Jennifer. The two NYTimes articles are informative particularly with respect to how vague the rules are and how easily they are circumvented or ignored. And greed, as usual, seems to have been a consideration. And no excuse for trying to save $3 a shot on a med they were reimbursed $300/shot for.
Reply | Report Abuse | Link to this@MikenStL : And thanks for pointing out that the autoclaving should be done last. I looked at the structure of methylprednisolone and it didn't appear to me to have any super heat sensitive functionalities, although I'm no expert on steroids. So I'm still amazed they sent out a non-sterile injectable, now maybe even more since a simple trip through a 'pressure cooker' would likely have prevented all this and wouldn't have cost hardly anything.
I have been following this news item for some time, and I remember reading elsewhere that drug preparations meant for injection into the spinal cord do not have preservatives. I was reminded of the case of an Indian minister (late Mr Murasoli Maran; see, for example: http://www.rediff.com/money/2002/sep/25maran.htm; September 25, 2002) who died after his mitral valve "prosthesis" got infected with a fungus. Even at that time I was wondering how the implant could have got the fungus, and what fungus it was.
Reply | Report Abuse | Link to this"In 1952, D.H. Peterson and H.C. Murray of Upjohn developed a process that used Rhizopus mold to oxidize progesterone into a compound that was readily converted to cortisone."
Reply | Report Abuse | Link to thisI suppose one mold is the same as another when it comes to drug production.