Officials at one of the nation's two main Marine Corps training centers are trying to contain an outbreak of a bacteria that sickened more than 100 recruits and possibly killed an 18-year-old private.

The outbreak of streptococcus A that began at the Marine Corps Recruit Depot last week prompted the base to suspend all strenuous physical activity for 3,000 recruits until at least Thursday, when the men's health will be reevaluated.

Maj. Gen. Jan Huly, the depot's commanding officer, said Monday he ordered the training suspension to prevent more recruits and instructors from overexerting themselves and getting sick.

"Let's give them a chance. ... I would rather err on the side of safety," Huly said.

The action came less than 24 hours after Pvt. Miguel Zavala of Greenfield died of a bacterial infection. He had sought treatment for a rash that quickly spread over his body, and he died within hours.

Zavala's infection could have been strep A or one of its equally dangerous cousins, said Capt. John Malone, medical services director for the Navy Regional Medical Center. The exact type of bacteria will be determined by an autopsy, he said.

Since the strep A outbreak was identified, more than 100 people from the depot have been admitted to the Navy Regional Medical Center, many suffering from pneumonia and other respiratory ailments.

On Tuesday, 41 people remained hospitalized. One recruit with a confirmed strep A infection was in critical condition in the intensive care unit, said Lt. Beatriz Yarrish.

Two other recruits have died at the base in recent weeks, but those deaths were not related to the outbreak. Pvt. Neal Edwards, 18, of St. Clair, Mo., died Nov. 24 of a heart ailment after completing an obstacle course. Pvt. Samuel J. Bruss, 19, of Kenosha, Wis., died Thursday when his lungs filled with fluid during survival training at the base swimming pool, officials said.

Strep A is a bacterium that in its most common form of illness causes strep throat. But in extreme cases it can simply overwhelm the body until organs cease functioning. It can also cause necrotizing fasciitis, a deadly flesh-eating disease. Malone said preliminary autopsy results showed no indication that Zavala had the flesh-eating strain of the bacteria.

Even before Zavala's death, Marine officials decided to give antibiotics to about 3,500 recruits and instructors as a precaution. Malone said they would continue to receive weekly penicillin shots and tests as long as the threat of contagion continued. About 1,000 senior recruits training at nearby Camp Pendleton will also receive antibiotics, Huly said.

The San Diego recruit depot is one of two bases used to train new Marines. The other is in Parris Island, S.C.