[Copesan University] ‘Spider Bites’: Maybe MRSA?

It might be because spiders can be a leading source of anxiety for many homeowners or because spiders rank as one of the top reasons that people start a residential pest management program with a pest management company. Whatever the reason, some people are blaming brown recluse spiders for skin infections that actually are caused by methicillin-resistant Staphylococcus aureus (MRSA).

MRSA is a bacterium that causes infections in different parts of the body. It’s tougher to treat than most strains of Staphylococcus aureus — or staph — because it is immune to commonly used antibiotics, such as methicillin, oxacillin, penicillin and amoxicillin.

Most often, MRSA causes mild infections on the skin like pimples or boils, but it also can cause more serious problems, such as necrotizing fasciitis, popularly known as “flesh-eating disease.”

SPIDER GETS A BAD RAP. Since both brown recluse spider bites and MRSA can cause a reaction to the skin that causes skin deterioration, some staph infections are misdiagnosed as spider bites.

This misdiagnosis is so widespread that brown recluse spiders are blamed for staph infections in areas where these spiders don’t even live. The spiders are indigenous to areas that range from southeastern Nebraska through Texas and east to Georgia and southernmost Ohio, but people have complained about their bites as far north as Canada and Alaska.

As indicated by its name, brown recluse spiders are known for their reclusive nature. They are not aggressive, and usually only bite when pressed against human skin, such as when tangled up in clothes, bath towels or bedding. Even then, most of these bites are minor with no necrosis, or flesh-eating wounds.
If a spider is implicated for a necrotic bite, verification of the genus and species should be performed by a qualified entomologist. It’s important to correctly diagnose the cause of the skin infection. If the cause is MRSA, the person needs to be treated quickly and correctly to limit the spread of infection, since it can be life-threatening.

ARE YOU AT RISK? About 30 percent of healthy adults carry staph bacteria on their skin or in their noses. MRSA infections usually are asymptomatic in healthy individuals and may last from a few weeks to many years. Patients with compromised immune systems are at significantly greater risk of developing an infection with symptoms.

Infections are most common among people who have weakened immune systems and are living in hospitals, nursing homes and other health-care centers. But outbreaks also have been found in such locations as gymnasiums, prisons and other places with close living quarters.

Hand washing is the best defense against MRSA. It is also important to immediately treat and cover all open wounds. Additionally, technicians should wear disposable gloves when working in areas where brown recluse spiders are abundant.

The author is an associate certified entomologist, and technical and training specialist for Western Exterminator Co., Anaheim, Calif. 

Copesan’s Internet training program, Copesan University, is now available to the entire pest management industry. Visit http://pctonline.com/copesan/ for available courses.