A 3-year-old girl’s holiday in Costa Rica was ruined by an iguana in more ways than one. The scaly reptile stole her cake, but not before biting her hand and transmitting a rare bacterial infection that endured for months, according to the girl’s doctors. Fortunately, the infection was treatable.
The unusual case will be presented later this month by doctors at the annual European Congress of Clinical Microbiology & Infectious Diseases, but details were made available to the public last week as a special early release.
The girl and her family were on vacation in Costa Rica. She was sitting on the beach eating cake when the iguana ran up, bit the back of her left hand, and absconded with the dessert. The girl was soon taken to a local clinic, where she had her hand disinfected and was given the antibiotic amoxicillin to protect against Salmonella bacteria, which is commonly carried by reptiles.
The wound healed, and all seemed well at first. But five months later, her parents noticed a small bump at the site of the bite. The bump grew larger and painful over the next three months, which prompted the family to take her to Stanford Children’s Health. There, doctors found and removed a nearly 1-inch mass from her hand. They also noticed a buildup of dead tissue and pus around the wound, often indicative of infection. The pus was taken for study, and the doctors soon identified a clear culprit for the trouble: a species of bacteria known as Mycobacterium marinum.
M. marinum is a member of the same family of bacteria responsible for human diseases like tuberculosis and leprosy. It’s known to cause tuberculosis-like illness in fishes and can sometimes cause skin infections in humans. These human cases, however, have typically been traced back to swimming or exposure to infected fish. As far as the doctors know, this is the first known case of M. marinum caught from an iguana bite. Some research has suggested that pet reptiles commonly harbor non-tuberculosis mycobacteria, the report authors note. And given the innate attributes of these reptiles, it’s not too surprising that iguanas can carry the bacteria.
“M. marinum prefers lower temperatures (30 degrees Celsius) for optimal growth, and it’s highly likely that the cold-blooded iguana, with body temperatures ranging from 22-37 degrees Celsius, may sustain these microbes as reservoirs,” the group wrote in their abstract of the case.
Mycobacteria infections tend to be hardy, and M. marinum is known to be resistant to many antibiotics, including amoxicillin. But once the doctors got the girl on a combination antibiotic therapy, the infection was successfully cleared. Rare as her case might be, the doctors say it should provide an important lesson to clinicians.
“The bite resulted in colonization by a bacterium rarely found in humans, and demonstrates that iguanas may be carriers of harmful bacteria capable of producing severe infections. This may help inform health care professionals of less commonly known bacterial infections following unusual zoonotic exposures,” they wrote.