VA Maryland Health Care System

Amy Horneman, PhD, chief of Microbiology and Molecular Diagnostics at the Veterans Affairs (VA) Maryland Health Care System’s Baltimore VA Medical Center and associate professor at the University of Maryland School of Medicine, is both a national and international expert on Aeromonas, the bacteria naturally occurring in all types of fresh and brackish water worldwide, including the Chesapeake Bay and its tributaries. The number of bacteria in the water increases during the warmer months—May to October—with the largest numbers present in the water in July and August. "There are 29 species of Aeromonas, and of those, eight are known to cause human illness," Horneman says. "When we engage in recreational activities such as boating, fishing, swimming, crabbing and water skiing, we expose ourselves to these naturally occurring bacteria that play an important role in aquatic eco-systems worldwide."

Aquatic recreational exposure with any one of the eight species can cause a range of physical illnesses. Accidently ingesting the water can cause diarrhea that is usually self-limiting and most often does not require medical intervention. But having an open cut or sustaining an injury such as a skin wound while swimming or boating on the Bay or any other brackish or fresh water source is another story, as evidenced by the flesh-eating syndrome caused by Aeromonas hydrophila that has afflicted a Georgia woman as noted in recent news stories.

Below are some safety tips for staying healthy during this summer’s water recreational activities:

• Aeromonas infections are generally treated with ciprofloxacin and bactrim (SXT, Septra) with successful resolution of the infections in most cases. Nearly all Aeromonads are resistant to commonly used antibiotics like penicillin, ampicillin, amoxicillin, and cephalothin (1st generation).
• Get prompt medical attention for skin, eye, respiratory and bloodstream infections. Any such wounds must be cleaned, dressed and treated with the appropriate antibiotics.
• Get prompt medical attention for cuts and/or wounds sustained in or near water sources. This includes cuts sustained on docks, piers, crab pots, from rocks and stones on a riverbed and any other accident that causes an opening for bacteria to enter the body.
• Without prompt medical attention, in certain cases, such wound infections can lead to the rapidly destructive disease known as "necrotizing fasciitis," which may result in the amputation of infected body parts and aggressive intravenous antibiotics in order to save the patient’s life.
• People of any age and any immune status can be infected with Aeromonas, but the very young and the very old populations are particularly susceptible to more severe diarrhea and more severe extraintestinal infections of the skin and bloodstream.