A Minnesota patient apparently was infected with an unusual germ from cadaver tissue used during routine knee surgery – a discovery that has led the nation’s largest tissue bank to ask 750 hospitals around the country to return 2,400 tendons and other body parts as a precaution.

A hospital reported the bacterial infection in September to the Centers for Disease Control and Prevention, which launched an intense, nationwide effort to search for more cases.

None has been found, but the incident shows the dangers that patients face when receiving such tissue and how dependent they are on the companies supplying it to ensure its safety.

A three-month investigation by The Associated Press, published in June, detailed problems that can arise from cadaver tissue used in more than a million medical procedures each year in the United States, especially knee and back surgeries.

Two scandals involving tissue suppliers have occurred in the last year, and the federal Food and Drug Administration has formed a task force to look for regulatory gaps that threaten safety.

The new case involves a company that many health officials and tissue company executives regard as an industry leader and standard-bearer: Musculoskeletal Transplant Foundation, or MTF, of Edison, N.J.

In more than 20 years of supplying 2.7 million pieces of bone, skin and other tissues, this is the company’s first reported infection, said a spokeswoman, Cindy Gordon.

In April, MTF noticed an increase in the number of tissues rejected for not passing sterility tests at its Jessup, Pa., processing plant – one of two such facilities it operates. Tissues were quarantined and about 150 that failed tests were destroyed, Gordon said.

In September, the CDC notified the company that an unusual infection had been reported in a Minnesota patient who received MTF-supplied tissue during surgery to fix a torn ligament a week earlier. Fluid from the patient’s knee joint grew Chryseobacterium meningosepticum – a germ never previously linked to tissue or organ transplants, said Dr. Arjun Srinivasan of the CDC.

“It’s a very rare cause of infections in the health care setting,” so the agency asked more than 1,000 public health officials, infectious-disease doctors, microbiologists and orthopedic surgeons around the country to search for additional cases, he said.

Five other people had received tissue from the same donor and none developed infections. MTF retrieved a sixth sample, and tests at CDC revealed it had the same bacteria as the Minnesota patient.

As a precaution, MTF decided to go back six months before the Minnesota case – to February – and try to retrieve as many of the 4,700 tissues supplied by the Jessup facility as possible, Gordon said. About 2,300 had already been implanted, and no other infections have been reported, she said. Hospitals have been asked to send back the remaining 2,400.

“This was not something that the FDA or the CDC asked us to do,” but a voluntary action to ensure patient safety, Gordon said.

The Minnesota patient made a full recovery after antibiotic treatment and still has the cadaver tendon, said Joel Osborne, MTF vice president of quality assurance and regulatory affairs. MTF would not identify the hospital or give details about the patient.

Srinivasan praised the company’s handling of the case.

“They’ve been very aggressive working with us” to try to locate the source of the germ, which may have been introduced during processing rather than originating with the donor, he said.

FDA spokeswoman Julie Zawisza emphasized that this case is not like the two earlier scandals in the human tissue industry, “where the suitability of the human donors was called into question.” She said MTF is cooperating with the FDA on the case.

AP-ES-11-22-06 1405EST