In rare case, man develops 'flesh-eating' bacterial infection on both legs, but 4 days apart

Streptococcus pyogenes, or scarlet fever, infection

An illustration of Streptococcus pyogenes, which can cause necrotizing fasciitis, a "flesh-eating" infection. (Image credit: Shutterstock)

A man was recently diagnosed with and treated for a "flesh-eating" bacterial infection in his right leg — only to have it spread to his left leg four days later, according to a new report of the case. 

The 58-year-old man arrived at the University General Hospital Gregorio Marañon in Madrid with severe swelling in his right leg, chest pain and a fever, all potential signs of necrotizing fasciitis, a rare and aggressive bacterial infection that sparks severe inflammation that can cause body tissue to die, or "necrotize." 

To treat the man's infection, the doctors administered a course of antibiotics into his veins, removed infected and damaged tissue from the leg and also performed a fasciotomy, which involves cutting connective tissue called fascia to relieve swelling and pressure on the underlying muscle, according to the case report, published July 25 in the journal Acta Biomedica

Several types of bacteria can cause this "flesh-eating" infection, and in this case, the man caught two: Streptococcus pyogenes and Staphylococcus aureus, the report's authors wrote. This isn't unheard of — past cases have also involved multiple species of flesh-eaters. But this is only the third documented case of "metachronous necrotizing fasciitis," in which multiple sites of infection appeared at different times, rather than within the same day.

Related: Florida man gets 'flesh-eating' bacterial infection after a relative bit him

In the hours after his initial treatment, the man's swelling and pain levels subsided. However, four days after the intervention, doctors noticed severe redness and blistering in the patient's left leg and swiftly performed another fasciotomy. Cultures isolated from the tissues confirmed that the same bacteria had slowly spread to the man's opposite side, so his doctors quickly applied antibiotics and removed the dead tissue.

Each year since 2010, there have been roughly 700 to 1,150 cases of necrotizing fasciitis caused by group A strep bacteria in the U.S., according to the Centers for Disease Control and Prevention (CDC), which also noted that this is likely an underestimate. "Even with treatment, up to 1 in 5 people with necrotizing fasciitis [caused by group A strep] died from the infection," the CDC website added. 

In this case, doctors administered early treatment with "aggressive and repeated" removal of damaged tissue, and the patient was discharged from the hospital a month later, with no complications during the follow-up, according to the case report. 

"We managed to keep our patient alive, without amputation or intervention by Plastic Surgery, and he recovered fully which is an excellent outcome from a very aggressive disease," the report's authors wrote. 

Kiley Price

Kiley Price is a former Live Science staff writer based in New York City. Her work has appeared in National Geographic, Slate, Mongabay and more. She holds a bachelor's degree from Wake Forest University, where she studied biology and journalism, and is pursuing a master's degree at New York University's Science, Health and Environmental Reporting Program.