CLEVELAND - Brian Russell had no idea what hit him.

A guy who routinely tackles 250-pound running backs head-on and occasionally gets pulverized by rampaging 350-pound NFL linemen for a living nearly saw his season end because of a microscopic germ.

The Cleveland Browns safety was flattened by a staph infection that hospitalized him during the preseason.

“I went from being in tiptop shape, to a few hours later, being knocked on my butt and having surgery,” Russell said, recalling his scary scrape with a skin bacteria that’s becoming harder for antibiotics such as penicillin to defeat.

“It happened just like that.”

Stories like Russell’s are becoming more common. Staph infections, in varying and sometimes deadly forms, are being reported in greater numbers across Ohio and nationwide as more virulent and resilient strains are infecting high school, college and professional athletes.

Football players, wrestlers and even fencers have contracted methicillin-resistant staphylococcus aureus, or MRSA, a serious superbug once isolated to hospitals and health-care settings that has found its way into locker rooms, weight rooms and athletic training facilities. Despite widely available information about the dangers of skin infections, staph has continued spreading.

“We don’t know why,” said Dr. Steve Gordon, the Cleveland Clinic’s department chairman of infectious disease. “It’s why we encourage everyone to practice proper hygiene, especially athletes who can be more at higher risk.”

An alarming rise in cases in the general population and athletic community has led to the Centers for Disease Control and Prevention to issue warnings about the dangers of staph. The CDC has worked closely with several sports organizations, including the NFL and NCAA to educate athletes on hygiene and preventive measures.

NFL players are advised to frequently wash their hands with soap and water, to report skin lesions to their team’s medical staff, to wash cuts with soap and water and apply the proper dressings daily.

Still, the problem has grown.

Since 2003, at least three NFL teams — the Browns, St. Louis Rams and Washington Redskins — have documented multiple cases of staph infections. Last summer, two Toronto Blue Jays players contracted staph, which prompted the club to have its clubhouse sterilized.

This fall, three high school football players in suburban Lakewood were hospitalized for staph infections. Their school was one of several in the Cleveland area that reported multiple staph cases this year. Health officials aren’t sure if the cases were related.

But even before the strain started spreading, staph has long been a health hazard for athletes who share towels, whirlpools and common areas like locker rooms and whirlpools.

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The bacteria is typically found in the nasal passages and on the skin of healthy people, but it is potentially deadly when it enters the body through scratches and scrapes.

Once inside, it can cause blood and joint infections, and pneumonia.

“I was in the most pain that I have ever felt ever in my life,” said Cavaliers forward Drew Gooden, who contracted a staph infection in his right leg three years ago while with the Orlando Magic. “I kept playing on it, thinking it was going to heal but the infection got worse and worse to the point where my leg swelled up and I couldn’t bend my knee.”

Athletes aren’t alone as targets for staph.

A study this year funded by the Centers for Disease Control and Prevention found that more than 59 percent of all skin infections in U.S. emergency rooms have been caused by MRSA. The staph, which enters through lesions in the skin and grows best in damp areas, has confounded doctors and pharmacists looking for an antibiotic to fight it.

The proportion of infections due to MRSA ranged from 15 percent to as high as 74 percent in some hospitals, the study showed.