Flesh Eaters

NDSU Microbiology
by NDSU Microbiology

Guest Blogger, Ellen Buysse, VMS Undergrad

You’re a doctor in the Emergency Room, and a patient and her husband come in. Something’s wrong with her foot. She complains of soreness and pain, as if she has “pulled a muscle.” You examine her and notice that her foot and ankle are black and blue. You ask the patient what happened, and she says, “My husband and I are on our honeymoon and we went hiking in the mountains.” Could this be a sprained ankle? You give the patient some pain medication and discharge her. Just as they are about to leave, you hear screaming. The black and blue is now scary black and blue…and spreading. What could this be?! You ask the husband again what happened, and he tells you they were washing their feet in a stream, and his wife cut her foot on a rock.

AHA!! You got it! She has necrotizing fasciitis, caused by a flesh-eating bacterium.

This is a scene from the hit ABC show, Grey’s Anatomy. After watching this episode, I was intensely fascinated, so naturally I Googled all about necrotizing fasciitis.

In necrotizing fasciitis, a bacterium reproduces and spreads rapidly once it enters the body. It infects flat layers of a membrane known as the fascia, which are connective bands of tissue that surround muscles, nerves, fat, and blood vessels. This disease can be caused by a number of bacteria: Streptococcus pyogenes (group A strep), Klebsiella, Clostridium, E. coli, Staphylococcus aureus, and Aeromonas hydrophila. The most common of these to cause necrotizing fasciitis, belongs to the group A strep, S. pyogenes.

How could such a teeny tiny bacterium, be so fatal?

S. pyogenes is a non-motile, Gram-positive, facultative, anaerobic bacterium, and it occurs as long chains of cocci (circles). This type of group A bacterium is beta-hemolytic (able to completely lyse red blood cells). On blood agar, clear zones of hemolysis appear around isolated colonies of S. pyogenes. This hemolysis is attributed to toxins called streptolysins. In a human, death of red blood cells means that less oxygen is getting to tissues, and the tissue eventually necrotizes, or dies.

Streptolysins can also destroy white blood cells, which are responsible for fighting off bacteria and disease; therefore, when these cells die, our bodies have a harder time defending against S. pyogenes.

However, treatments are available. Strong antibiotics, given through a needle into the vein, are the best option for treating necrotizing fasciitis. When antibiotics are not able to reach the dead tissue, surgical removal of the tissue is needed. In the show, the doctors had to amputate the woman’s entire leg in order to keep the bacterial toxins from spreading to other tissues of her body.

Although this disease is treatable, 1 out of 4 people with the disease do die from it. Often, diseases like this can be prevented. Had the woman cleaned and properly taken care of her cut right away, by disinfecting it and then wrapping it up from exposure to the environment, she could have saved herself from a tremendous amount of pain…and saved her leg.

Our world is full of microbes, and although the majority of these organisms are beneficial, some can do a lot of damage. So, the next time you get a cut, or some type of open wound, be sure to properly take care of it because it’s either that or the possibility of losing an important limb…or maybe even your life.

Image: CDC

This entry is part of the MICR 354 (Scientific Writing) student-blog series.