Australian researchers report that dozens of patients developed potentially serious wound infections after playing a game of “mud football,” a form of rugby played in a muddy field.

The risk of infection with this bacterium, known as Aeromonas hydrophila, remains low for most people, but individuals playing sports in the mud should take special precautions, according to the study’s lead author.

“This remains an unusual infection, and people should not be unduly concerned unless they have skin wounds that become infected following exposure to mud or stagnant water,” Dr. Gary K. Dowse of the Department of Health in Perth told Reuters Health.

But if people do develop wound infections after contact with mud or stagnant water, they “should see a doctor promptly to ensure they are treated appropriately, as Aeromonas infections can be serious,” Dowse said.

“In addition, people with cuts and scratches should try to avoid exposure to mud and stagnant water, either recreationally or occupationally, and should clean any wounds promptly after such exposures,” Dowse said.

A. hydrophila is a bacterium that lives in fresh and brackish water. Fish, amphibians and mammals, including people, can become infected with the pathogen through open wounds or by drinking contaminated water. The bug can cause gastrointestinal symptoms and wound infections in people.

A day after a 2002 charity mud football game in the small Australian town of Collie, 26 players were seen at an emergency room for infected scratches and pustules on their arms, legs and torso. Most people had 20 to 30 lesions on their skin, but several had more than 100.

Most patients were prescribed antibiotics to treat the infections. But many were later switched to another antibiotic after doctors at the hospital determined that A. hydrophila was to blame for the symptoms, because the original drug was unlikely to be effective against this type of bacteria.

Conditions at the mud field were perfect for nurturing A. hydrophila. For a month before the game, the field was watered with water from a nearby river. The combination of warm temperatures and stagnant water was an “ideal environment” for the growth of the bacterium, according to the report.

People who play mud football may reduce their risk by using fresh water and by making sure that the mud is free of gravel, sticks and straw that might cause cuts and scratches, Dowse said.

Another lesson to be learned from the outbreak, Dowse said, is that doctors should consider the possibility of A. hydrophila infection in people who develop wound infections after exposure to mud or stagnant water so that they choose the appropriate treatment.

SOURCE: Clinical Infectious Diseases, April 15, 2004.