Stem cell injections in Mexico can be hazardous. Report identifies US victims.

Health experts are alerting travelers considering medical care abroad about a trio of recent drug-resistant bacterial infections caused by stem cell injections at Mexican clinics.

After stem cell treatments abroad, three Americans became infected by mycobacterium abscessus, a distant relative of the bacteria that cause tuberculosis and leprosy. In a report published Thursday, U.S. medical experts said they fear additional infections from the injections could have been missed. Two patients shared bacteria with identical genetic material even though their procedures happened in clinics hundreds of miles apart. The incidents have raised concerns about others who sought stem cell injection treatments abroad. The procedure is not approved by the U.S. Food and Drug Administration.

“It's hard to put an exact number, because unfortunately, nobody seems to be monitoring this very closely,” said Dr. Charles Daley, a pulmonologist at National Jewish Health, a hospital in Denver. “There's very little oversight.”

Medical tourism:Why are more people traveling abroad for cosmetic surgery, and what are the risks?

Medical tourism, when Americans travel abroad for treatments, has been on the rise in recent years. As many as 320,000 U.S. citizens travel internationally for medical care each year, according to the State Department. The Centers for Disease Control and Prevention estimates the number of medical tourists each year is likelier in the millions. Mexico is a common destination for dental and plastic surgery. There isn't firm data on the prevalence of travel for embryonic stem cell injections, but studies have shown the dangers of undergoing the unproven treatment. Several websites promote what they say are cheap, safe and legal options for injections in Mexico.

Hospitals often refer people with abscessus infections to the National Jewish Health’s mycobacterial and respiratory infections division, where Daley is chief. He and other researchers published their findings Thursday afternoon in the CDC’s Morbidity and Mortality Weekly Report. 

The abscessus bacterium can cause infections – often in the skin or lungs – that are difficult to treat, even with antibiotics. They fester in open wounds or injections. Infections of this type are often caused by medical devices that haven’t been properly disinfected. They can cause boils and pus-filled cysts, according to the CDC. Other symptoms of infection are fever, chills and muscle aches. Infections are associated with cosmetic surgeries. 

In spring 2023, Daley saw an Arizona man in his 60s with an abscessus bone and joint infection on his right elbow after he'd gone for embryonic stem cell injections at a clinic in the Mexican state of Baja California the previous year. 

In October 2022, a Colorado woman in her 30s traveled to a different Baja clinic to get embryonic stem cells injected into her spine to treat multiple sclerosis. She developed headaches and fevers similar to meningitis, an infection that inflames fluid and membranes around the brain and spinal cord. After being treated at the University of Colorado in Aurora later that year, she was referred to National Jewish Health. 

National Jewish Health treated a third case, a Colorado man in his 60s, who received stem cell injections in his knees for osteoarthritis in October 2022 in Guadalajara, an urban hub in central-western Mexico. He subsequently developed infections in both knees. 

Researchers found all three patients had received stem cell injections. They then worked to sequence the bacterium’s genetic material. In the cases of the Arizona man and the Colorado woman who had received injections in Baja, they found the same rare sub-species of the bacterium. The Baja clinics were 167 miles apart. 

The details for the third case, the Colorado man, remain unclear. Daley said cultures for his bacterium strain weren’t saved by Mexican officials. 

Health officials with Colorado, Arizona and the CDC contacted health authorities in Mexico, where staff said they weren’t aware of the infections, Daley said. It doesn’t appear there’s any investigation into a possible outbreak, he added. 

Over a year-and-a-half after their treatments, all three patients are still in ongoing treatment for their infections. Daley said they are on a combination of antibiotics commonly used to treat pneumonia and leprosy.

Doctors are searching for additional cases of patients who may have developed infections after stem cell injections. Daley said it makes sense why Americans might opt for cheaper options abroad, but people should have a "buyer beware" notice.

“We understand the pressure to do it,” Daley said. “But it comes with risks that I don't think people understand.”