Deaths Blamed on Mysterious Microbe with Anthrax Genes

Genome News Network ^ | June 4, 2004 | Kate Ruder

[Mitchell]

Deaths Blamed on Mysterious Microbe with Anthrax Genes

By Kate Ruder

Posted: June 4, 2004

Last year two hospital patients from different cities in Texas died of severe pneumonia that appeared to be caused by inhalation anthrax. Yet neither patient was infected with the bacterium that causes anthrax, Bacillus anthracis.

Instead, DNA tests indicated that both patients became infected by another species of bacteria that carried the lethal anthrax genes. The bacterium, called Bacillus cereus, typically causes mild food poisoning.

B. cereus from Louisiana patient (top) and B. anthracis. Both microbes have capsules that may protect them from a person's immune system.

Image courtesy PNAS.

When the Texas cases came to light, researchers at the U.S. Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, were sequencing the genome of a strain of B. cereus isolated from a man in Louisiana who, in 1994, developed severe anthrax-like symptoms.

The researchers now report that B. cereus can indeed carry lethal genes of the anthrax bacterium. The Texas and Louisiana patients were all metal workers and appeared to have inhaled the dangerous bacteria, although scientists do not know how.

These are the first cases in which anthrax genes have been discovered in an organism other than B. anthracis, and the findings raise concerns about the prevalence of the previously unknown pathogen—and our preparedness to detect and respond to it in the event of a biological attack.

For example, tests used to detect anthrax during a suspected bioterrorism incident might not pick up the equally pathogenic bacteria B. cereus.

Alex Hoffmaster of the CDC found the Louisiana strain of B. cereus that tested positive for anthrax genes while he was looking back at samples from patients with fatal or near-fatal disease.

"Either I had made a mistake or this was a really interesting isolate," says Hoffmaster.

He sent the CDC sample to The Institute for Genomic Research (TIGR) in Rockville, Maryland, and scientists there sequenced its genome in just a few short weeks. They then compared it to the genomes of related bacteria such as the B. anthracis Ames strain used in the 2001 U.S. mail attacks and other strains of B. cereus.

The CDC bacterium has genes nearly identical to anthrax toxin genes that cause disease in humans and other animals. And the bacterium caused anthrax-like illness in mice, the researchers report.

"It was completely unexpected to sequence the genome and see toxin genes in B. cereus identical to ones found in B. anthracis," says Jacques Ravel of TIGR, who led the sequencing effort.

The findings appear in Proceedings of the National Academy of Sciences this week.

How did the strains of B. cereus acquire anthrax genes? "That is still a mystery," says Ravel.

He and others suspect that the two species of Bacillus bacteria, which both live in the soil, might have swapped genes at some point during evolution. There is no evidence that someone engineered the bacteria to carry these genes.

. . .

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Hoffmaster, A. R. et al. Identification of anthrax toxin genes in a Bacillus cereus associated with an illness resembling inhalation anthrax. Proceedings of the National Academy of Sciences 101, 8449-8454 (June 1, 2004).

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[Mitchell]

Ping.

[TomGuy]

Nothing to see here, folks. Now move along. Quickly! Quickly. Don't dauddle!

UNKNOWN VIRUS HITS KANSAS WHEAT FIELDS
			Posted by genefromjersey On News/Activism 06/03/2004 6:30:40 PM CDT with 50 comments 06/03/04 | vanity An unidentified wheat virus has appeared in fields throughout western Kansas. The unknown pathogen causes the leaves to turn yellow and die.These symptoms are also associated with head death,wheat streak mosaic,and freezing; however,University of Kansas researchers have ruled out these possible causes. Researchers note evidence of the virus is in almost every field-although it has not yet destroyed the crop. University of Kansas virologists,with the help of researchers in Winnipeg,are trying to identify the proteins involved in the destruction of affected plants,so the genetic sequences may be compared to pathogens found in other parts of the world.

[Judith Anne]

Thanks for posting.

[TrebleRebel]

What I find most disconcerting with this story is that, at least for some period of time, possibly a few weeks after the deaths, there was a high probability that 2 people had died from inhalational anthrax. Were co-workers of these people offered antibiotic treatment? In fact, did anybody even know about this at the time? And if it leaked out, would Tommy Thompson have claimed they both recently drank from streams?

[steplock]

"...genetic sequences may be compared to pathogens found in other parts of the world"

That will probably have much success than checking for "freeze" injuries in June that "University of Kansas researchers have ruled out" .

idiots!

[Servant of the 9]

Ping

Either a remarkable case of teh bacterial gene swapping process, or Biowar.

So9

[null and void]

Note the date, 1994...

[browardchad]

Only one of the three died in '94 (in Louisiana); the other two died last year in Texas.

According to the article, the link is that they were all "metalworkers."

Coincidence?

[Mitchell]

Your point is well-taken.

Maybe I just missed it, but as far as I'm aware, this story didn't appear in the media anywhere until the Proc. Natl. Acad. Sci. article a couple of weeks ago. And even after that , it seems to have been picked up only by the "Genome News Network".

I find the lack of attention surprising -- I think this is one of the most interesting stories on anthrax I've seen for a long time.

[Clara Lou]

Interesting.

[Mitchell]

Note the date, 1994...

The two deaths in Texas were in 2003.

1994 was the date of an earlier and apparently similar case of a B. cereus infection with anthrax-like symptoms. That case was the one in Louisiana.

[demnomo]

The Influenza Pandemic of 1918 was probably not bio-engineered either, but the governments at that time kept the real details quiet so as not to "panic the population." Some researchers claim that this silence strategy strengthed rather than curbed the spread of that deadly enfluenza epidemic.

No need for "panic" now, but I hope and pray our governments are not going to cover up the obvious should an outbreak of deadly illness strike a populace. Thank goodness for the internet and faster, more sophisticated mass communication methods.

[genefromjersey]

I read this story a few days ago,and considered writing it up, BUT: The GNN article does not make clear whether this was a small,localized strain of B.cereus,or whether this is true of ALL or MOST B.cereus.

There's a heck of a big difference !

Personally, I'm having a little trouble with the concept of "evolutionary gene swapping" - something we should have seen a great deal of over the years if possible.

I'd really like to hear what a competent biologist,specializing in this field,has to say !!

[Mitchell]

The GNN article does not make clear whether this was a small,localized strain of B.cereus,or whether this is true of ALL or MOST B.cereus.

B. cereus is well-studied, so I think this would have been observed before if it were common.

As for gene swapping, it's very common. My understading is that this is a major mechanism underlying genetic variation. (Do a search in Google for "gene swapping", or, as you say, ask any competent biologist.)

As the article says, there's no reason to think that this was bioengineered. But it does indicate the sorts of things that would be possible with bioengineering.

[Mo1]

.

[ATOMIC_PUNK]

Bacillus Cereus

Comparison of B. cereus Enterotoxins

Property	Diarrheal Toxin	Emetic Toxin
nature	protein~40 kDa	peptide~5 kDa
stabilities	heat stable 450C, 30 min	stable 1260C, 90 min
	unstable 560C, 5 min
pH	most stable pH 4-11	stable pH 2-11
enzymes	sensitive to pronase, trypsin	resistant to pepsin, trypsin
storage	unstable	stable
production
in foods	sometimes preformed	preformed
lab media	complex	rice slurry
opt temp	32-370C	25-300C
growth
	late exponential	stationary
activities
monkeys	diarrhea in 1-3 hr	vomiting in 1-5 hr
ileal loop	+ (also necrosis)	-
skin perm.	+	-
mice	lethal	?
cell cult.	cytotoxic	?
antigenic	+	-
action	tissue damage	?
	altered perm.
	adenyl cyclase	?

Diagnosis of Human Illness:	Confirmation of B. cereus as the etiologic agent in a foodborne outbreak requires either (1) isolation of strains of the same serotype from the suspect food and feces or vomitus of the patient, (2) isolation of large numbers of a B. cereus serotype known to cause foodborne illness from the suspect food or from the feces or vomitus of the patient, or (3) isolation of B. cereus from suspect foods and determining their enterotoxigenicity by serological (diarrheal toxin) or biological (diarrheal and emetic) tests. The rapid onset time to symptoms in the emetic form of disease, coupled with some food evidence, is often sufficient to diagnose this type of food poisoning.
5. Associated Foods:	A wide variety of foods including meats, milk, vegetables, and fish have been associated with the diarrheal type food poisoning. The vomiting-type outbreaks have generally been associated with rice products; however, other starchy foods such as potato, pasta and cheese products have also been implicated. Food mixtures such as sauces, puddings, soups, casseroles, pastries, and salads have frequently been incriminated in food poisoning outbreaks.
6. Relative Frequency of Disease:	In 1980, 9 outbreaks were reported to the Centers for Disease Control and included such foods as beef, turkey, and Mexican foods. In 1981, 8 outbreaks were reported which primarily involved rice and shellfish. Other outbreaks go unreported or are misdiagnosed because of symptomatic similarities to Staphylococcus aureus intoxication (B. cereus vomiting-type) or C. perfringens food poisoning (B. cereus diarrheal type).
7. Course of Disease and Complications:	Although no specific complications have been associated with the diarrheal and vomiting toxins produced by B. cereus, other clinical manifestations of B. cereus invasion or contamination have been observed. They include bovine mastitis, severe systemic and pyogenic infections, gangrene, septic meningitis, cellulitis, panophthalmitis, lung abscesses, infant death, and endocarditis.
Bacillus cereus and other Bacillus spp.

[Mitchell]

No need for "panic" now

This was last year and, in and of itself, was a minor incident (two cases). It was almost certainly natural.

But it's a wake-up call. This ought to well-publicized so that people (medical professionals, homeland security officials, and the population at large) are aware of and on their guard against the sorts of things that could happen in a bioatack.

[Mitchell]

Thanks for posting that. It's consistent with everything I've read in the past about B. cereus -- nothing about symptoms similar to inhalation anthrax after respiratory exposure.

In fact, B. cereus is used as an anthrax simulant in experiments because it is relatively innocuous.

[Mitchell]

bioatack = bioattack