A Texas MedClinic doctor said Wednesday that a deadly strain of staph infection called MRSA, believed to have killed a 17-year-old Virginia high school senior, is becoming increasing common in San Antonio.

Dr. David Gude of the Texas MedClinic said last year the clinic recorded more than 600 MRSA cases, but this year, it has recorded almost that many being reported on a monthly basis.

"This year we are seeing 300 to 500 cases per month across our locations," Gude said.

On a national scale, MRSA is suspected of killing more Americans each year than the AIDS virus.

Gude said antibiotics are completely useless in treating the infection that is commonly spread through day cares, gyms and locker rooms.

Gude said a person needs to seek medical attention if they have what looks like a bite or an abrasion, warm to the touch, that does not heal in 48 hours.

He said if MRSA is not treated, it can spread to the bloodstream.

Gude said good sanitation practice could prevent contracting MRSA.

"Wash your hands a lot because good hand-washing is the No. 1 way to protect yourself," he said.

Symptoms of MRSA may include redness, warmth, swelling, tenderness of the skin and boils or blisters.