Lessons from the recent tuberculosis bone graft outbreak
A recent tuberculosis outbreak linked to contaminated bone graft material cost one person’s life and infected at least four others. The incident underscores the inadequacy of current tuberculosis testing for tissue donations — and the urgent need for stronger regulation.
Tuberculosis is caused by a bacterium called Mycobacterium tuberculosis. The bacteria usually infect the lungs, but they can attack any body part, such as the kidney, spine or brain. If left untreated, tuberculosis can become fatal.
The contaminated product, ViBone Moldable, was used in at least 36 patients who underwent surgical or dental procedures earlier this year. The CDC says the contaminated product was shipped to California, Louisiana, Michigan, New York, Oregon, Texas and Virginia.
This is the second tuberculosis outbreak in two years linked to Aziyo Biologics. Eight people died in 2021, when the same type of bone repair product used in spinal and dental surgery was also contaminated with the bacteria.
There is currently no commercially available tuberculosis test for the bone tissue used in spinal or dental surgeries. Even if such a test were developed, neither the FDA nor the American Association of Tissue Banks mandates the screening of donor materials for tuberculosis. This is a huge oversight for a potentially fatal disease, but several complications must be overcome to develop an effective testing and screening process.
Currently, a bacteria culture test of donor tissues for Mycobacterium tuberculosis is the gold standard for tuberculosis screening. Unfortunately, bacterial cultures from tissues take six to eight weeks to finalize, which may not be a reasonable timeline for certain tissues.
Polymerase chain reaction (PCR) testing is faster and cheaper but has two major problems: false-positive reactions due to contamination with DNA fragments from previous PCRs, and false-negative reactions caused by inhibitors that interfere with the PCR. Currently, the only FDA-approved PCR tests are for use with phlegm specimens, which are much harder to collect than blood or urine. The Interferon Gamma Release Assays used in living donors require viable and intact immune cells to produce accurate results, which means that this method is not recommended for deceased donors.
Bone tissue donors must also be more aggressively screened for risk factors, including travel to countries with high TB levels. The tissue donor associated with the 2021 outbreak had frequently traveled to an unidentified country where the annual number of new TB cases is eight times higher than in the U.S.
Despite tuberculosis cases in the U.S. increasing to levels not seen since before the COVID-19 pandemic, there’s very little investment in tuberculosis research or tests for the bacterium. This outbreak should be a stark warning that tuberculosis cannot be ignored, and the FDA and device manufacturers should invest in more effective tests, screenings and regulations.
Dr. William Haseltine is a former Harvard Medical School professor and founder of the university’s cancer and HIV/AIDS research departments. He serves as Chair and CEO of the think tank ACCESS Health International.