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July 24, 2004

Flesh-eating Bacteria Doing Their Thang

Necrotizing Fasciitis, or flesh-eating bacteria, came into the general awareness a few years ago when the media reported on several instances of people undergoing emergency surgery to remove huge sections of tissue -- sometimes even hands or limbs -- to survive particularly nasty bacterial infections. These infections, though apparently very rare, make up for that with their fearsome symptoms and aggressive progress.

I've noticed several stories in the last couple of weeks involving several different types of flesh-eating bacteria. In Texas, several Gulf fisherman were infected recently with Vibrio bacteria when they got seawater in cuts. For one man, Charles Newton of Rockport, it took only 48 hours before he was rushed to the hospital, "with an extremely high fever and violent nausea," according to his daughter. "He was disoriented, dizzy and very weak." In surgery, Newton had a long section of infected flesh removed from his arm.

Last month in Louisiana, Louis Roach of New Orleans was stabbed in his hand by the sharp fin bone of a catfish he'd just caught. Within hours, he'd become dizzy and blacked out. Not many days later, both his arm and leg had been amputated, after the bacteria -- identified as Vibrio vulnificus -- had spread rapidly through his body. Flesh-eating bacteria like Vibrio typically do their worst in people with weakened immune systems, and Roach reportedly had liver problems that may have made him more susceptible to the bacteria's toxin. In the detailed and folksy New Orleans Times-Picayune account of Roach's misfortune, it's noted that the CDC estimates "there are an average of 50 confirmed cases of [Vibrio] infection annually. Of those, 45 patients will need to be hospitalized and 16 will die." That's not enough of a risk for people to stop enjoying the water, obviously, but should cause those with weakened immune systems to pay attention when they visit warm waters of the southern U.S. or the tropics.

In addition to the flesh-eating phenomenon, various Vibrio species are also responsible for infecting shellfish like shrimp and oysters, which then cause illness (nausea, cramps, diarrhea) in the people who eat them.

Another story on the wires today describes the ordeal of Paul deJong of Sioux Falls, South Dakota, who returned from Cozumel, Mexico with a spider bite this spring. Stiffness in his leg eventually turned into fever and chills, and before long he was in the ER, "where doctors found a flesh-eating bacteria that was spreading at the rate of 1 inch per hour." After four surgeries the infection was stopped, but deJong still hasn't returned to his job at the local Landscape Garden Center.

DeJong's infective agent was not mentioned, but many cases of Necrotizing Fasciitis (NF) are caused by Group A Streptococcus bacteria -- a virulent strain of the same bacteria responsible for common strep throat. As noted above, NF infections can be so rapid and life-threatening that radical measures must be taken to save lives. NF survivors and victims' family members have created an organization to inform the public and help one another deal with the consequences of NF.

Coincidentally, a group of scientists at Rocky Mountain Laboratories in Hamilton, Montana, recently announced they've discovered how the Group A strep germs make such rapid advances in NF cases. Apparently the bugs trick the body's neutrophils -- front-line defense cells that engulf the bacteria and then destroy them -- into destroying themselves before they can neutralize the trapped strep cells. This gives the bacterial cells enough time to reproduce and spread, with many of the bacterial cells repeating the process of neutrophil destruction.

Following are symptoms of NF infection (courtesy of WebMD):

* Sudden, severe pain in the affected area.
* Fever, nausea, vomiting, fatigue, and other flulike symptoms.
* Redness, heat, swelling, or fluid-filled blisters in the skin over the affected area. If the infection is deep in the tissue, these signs of inflammation may not develop right away.

Later symptoms may include:

* Signs of shock (including confusion, fainting, or dizziness), which are often made worse when you rise from a sitting or reclining position. These symptoms are caused by a drop in blood pressure.
* Scaling, peeling, or discolored skin over the affected area, which are signs of tissue death, or gangrene.

2 Comments:

At 8/06/2004 12:19 PM, Blogger Don said...

According to Webster's:
(http://www.webster-dictionary.org/definition/Nosocomial)

"1. Of or pertaining to a hospital; as, nosocomial atmosphere.
"2. Acquired in a hospital; as, a nosocomial infection."
---------------
Thus, a nosocomial infection is one for which the hospital environment and equipment is responsible.

It gets better, though: the adjective "iatrogenic," according to Webster's, refers to something that is:
"induced by a physician's words or therapy (used especially of a complication resulting from treatment)."
(http://www.webster-dictionary.org/definition/iatrogenic)

Therefore, a nosocomial infection is one that you wouldn't have acquired if you hadn't gone to the hospital, while an iatrogenic infection is one that you wouldn't have acquired if you had not been personally examined or otherwise treated by your doctor, nurse or other medical worker.

Here's an excellent summary (MS Word document) of the varied causes of these infections, written by Professor Min-Ken Liao, PhD, of Furman University:
http://facweb.furman.edu/~liaomin-ken/Topic19.doc

For info on how nosocomial/iatrogenic infections have influenced the development of MRSA/VRSA/MRE and other deadly bacteria strains -- and how smart administrators have fought back -- I highly recommend reading "The Killers Within: The Deadly Rise of Drug-Resistant Bacteria," by Michael Shnayerson & Mark J. Plotkin. It's both informative and enjoyable to read.

 
At 8/08/2004 9:03 PM, Blogger Michael said...

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