Tag Archives: immunology

Flesh-Eating Bacteria

10 Apr

I was gearing up to write a super-awesome article on flesh eating bacteria! It’s something everyone has heard about, though I can guarantee you that it’s not as scary as flesh-eating mould. (Flesh eating mould is one of the few things that truly grosses me out. I can handle flesh eating bacteria any day of the week, but the flesh eating mould is far more insidious. But that’s a tale for another day.)

However, Keith Veronese of I09 beat me to it, and did a far better job that I would have done. I added a few pictures, because there is no such thing as too many bacteria photos. Enjoy!

Does flesh-eating bacteria really make a meal out of you?

You first notice a bump — a tender, cherry red bruise. Over the next 12 hours, the center of this painful spot on your leg becomes dark violet in color. A day later this raised red bump ruptures and fluid oozes forth. I hope you are on the way to the hospital at this point, because flesh-eating bacteria might be running amok in your body.

These microbes have appeared in such films as the late-night scifi flick Cube Zero, in which a prisoner is sprayed with flesh-eating bacteria and melts before the audience’s eyes. But does this horrifying bacteria act as quickly as depicted in movies? And more importantly, do the bacteria actually dine on your flesh?

Does flesh-eating bacteria really make a meal out of you?

Flesh-eating bacteria formally goes by the mildly less frighting name necrotizing fasciitis in medical circles. Necrotizing fasciitis occurs through a cascading series of events, with the bacteria Clostridium perfringens and Streptococcus pyogenes commonly initiating the infection. The bacteria often enter through an open wound, particularly when the wound is left exposed in a foreign environment like seawater or sewage.

These bacteria lurk in benign places — a 14-year-old in South Carolina contracted the illness in2009 after removing rocks from the bottom of a local lake. He lost half of his palate, a portion of his nose, and several teeth as surgeons extracted flesh to prevent spreading of the bacteria. In another incident, the guitarist of the venerable thrash metal band Slayer contracted the diseasefrom a spider bite in 2011.

In necrotizing fasciitis, the bacteria doesn’t actually eat the flesh of your body. The bacteria sneaking their way into your body spur on the release of proteins, which have a toxic effect in increased quantities. Phospholipase A2 and antigens released by the bacteria enter the cells of your skin, fat, and the connective tissue covering your muscles and begin wreaking havoc. (Here’s an image of a necrotizing fasciitis infection, but be forewarned that it’s very graphic. Like, Krokodil graphic.)

Phospholipase A2 is often found in snake venom and bee stings. When excess Phospholipase A2 appears in the body, your cells respond by releasing arachidonic acid. The presence of additional arachidonic acid disrupts cells, causing inflammation and pain. Fortunately, the effects of Phospholipase A2 can act as a warning sign for those with necrotizing fasciitis, hopefully leading an individual to seek out treatment.

The antigens released are commonly a type of superantigen that causes non-specific activation of T-cells, or those cells that are the primary line of defense in your body’s immune system. The over-activation of T-cells leads to the release of enormous quantities of cytokines (a small protein) at the infection site. The cytokines start a cell signalling cascade that begins the destruction of tissue cells in the region. The foreign bacteria causing necrotizing fasciitis do not eat your flesh, but they do something a little more sinister — these bacteria turn your flesh against you.

What happens should you contract necrotizing fasciitis? Patients must receive intravenous antibiotics immediately and a series of surgical operations to remove dead tissue. If the operations are unsuccessful and the necrotizing fasciitis is contained to an appendage, amputation of an infected arm or leg is the safest course. Patients with necrotizing fasciitis often undergo hyperbaric oxygen treatment, with the hope that the increased oxygen levels help the body heal.

Several hundred individuals contract necrotizing fasciitis in North America each year. Even with treatment, 25% of patients that contract necrotizing fasciitis die from complications of the disease. Years of skin grafts and pain management follow those who are lucky enough to survive.

Also, an even scarier type of necrotizing fasciitis, Fournier gangrene, targets the perineum, and more specifically, the groin and genitals. Modern cases are not common, but the historical autopsies suggest that the Roman emperor Galerius and Herod the Great died of this malady. A 69-year-old Herod suffered from a combination of kidney failure and Fournier gangrene, degrading his flesh to the point that worms and maggots moved in and out of the affected areas freely. Fournier gangrene, when it appears in modern society, carries a 40% mortality rate.

The top image is a promotional photo for AMC’s The Walking Dead. Images linked from the article: Late diagnosed necrotizing fasciitis as a cause of multiorgan dysfunction syndrome: A case report and the CDC.

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Microbiology Science Quickies: Coral Herpes, Dangerous Grilling, & Bacterial Communications

2 Apr

Ahhhh! So much science and health stuff to share! My poor web browser is drowning again!

You may have heard that the world’s coral reefs are collapsing, and while there are many theories, we have yet to fully explain why. It’s often assumed that climate change and pollution are the main culprits, and there is probably truth to that.
But now scientists are examining another culprit: a virus.
Particularly, a herpes virus.
From microbiologist Rebecca Vega-Thurber: “We were shocked to find that so many coral viruses were in the herpes family. But corals are one of the oldest animal life forms, evolving around 500 million years ago, and herpes is a very old family of viruses that can infect almost every kind of animal. Herpes and corals may have evolved together.”


That being said, I do not recommend you try to pick up chicks by telling them your penis can vanquish marine ecosystems.

As the days get longer and summer approaches, many people are firing up their grills to participate in the American tradition of consuming charred meat. However, grilling is not without it’s health risks. Along with E.coli and carcinogen formation, the traditional wire grill brush may also make you sick, NPR reports. SOme good news though: the use of antioxidant spices may reduce the negative effects of those delicious fatty meats, especially rosemary.  Additionally, proper grilling technique will typically kill the deadly E.coli o157:H7 strain.

Bacteria are pretty interesting critters that can not only talk to each other, they play prisoner’s dilemma to decide their fate.
“When faced with life-or-death situations, bacteria use an extremely sophisticated version of “game theory” to consider their options and decide upon the best course of action.” Of all the microbiology-related articles I’ve read lately, this is one of the most interesting.

According to Yale University, just the mere presence of a person in the room can cause bacterial levels to spike. When a person enters the room, they stir up bacteria. Says the article: “Many previous studies have surveyed the variety of germs present in everyday spaces. But this is the first study that quantifies how much a lone human presence affects the level of indoor biological aerosols.”

In biochemical news, researchers have captured the first images of vitamin B12 in action. In 3D, no less! Scientists from the University of Michigan Health System and the Massachusetts Institute of Technology report they have created the first full 3-D images of B12 and its partner molecules twisting and contorting as part of a crucial reaction called “methyltransfer.” This reaction is vital both human cells and in bacteria that consume carbon dioxide and carbon monoxide. Such bacteria live in the guts of humans, cows, and other animals, and aid with digestion.

Grammatical Allergies

13 Mar

Would grammatical allergies would be classified as Type 1, Type 2, Type 3, or Type 4 hypersensitivity? Are the antibodies formed IgG or IgM?

These are the thoughts that keep me up at night.