The sepsis death of a recipient of Faecal Microbiota Transplantation (FMT) that contained an extended-spectrum beta-lactamase (ESBL)–producing E. coli strain should be a warning against complacency on risks, according to US researchers.
The death was one of two serious cases of infections reported from a single FMT donor whose samples were subsequently found to contain the same strains of ESBL E. coli.
Both cases occurred in patients who had additional risk factors for sepsis – one 60-year old man had cirrhosis with hepatic encephalopathy, while the fatal incident occurred in a 79-year old man who had haematologic dysplasia that was being treated by means of haematopoietic-cell transplantation.
Writing in NEJM, the researchers says the cases occurred when FMT was being used as part of clinical trial setting at the Massachusetts General Hospital, and Harvard Medical School.
The patients were taking part in studies in 2018, at which time FMT donors were being screened for numerous risk factors but not for presence of ESBL-producing E. coli.
While undergoing hematopoietic-cell transplantation one patient received FMT therapy in the form of oral capsules manufactured from frozen samples from a donor. But eight days after the FMT procedure the man developed fever and bacteraemia and his condition rapidly deteriorated despite the prompt use of antibiotics including merepenem. He died two days later, and blood cultures showed the presence of ESBL-producing E. coli.
Genetic tests showed this strain was the same as that found in another patient who also developed serious sepsis after receiving FMT from the same donor. This patient survived after aggressive use of antibiotics
Subsequent investigations showed the ESBL-producing E. coli strain was detected in about half of 22 other recipients of FMT samples from the same donor. In effect this meant the FMT procedure had transmitted the ESBL resistance to the recipients, the report authors said.
They said the clinical trial centre had since adopted FMT donor screening for ESBL, but the seriousness of the adverse events showed the need for ongoing vigilance and weighing up of benefits and risks of FMT depending on the individual patient’s circumstances.
An accompanying commentary went further, saying that the dynamic nature of the microbiome and antibacterial resistance showed that a ‘one-size fits all’ approach to FMT risks was not enough.
“FMT carries a risk of infectious hazards that needs to be taken seriously,” wrote Dr Martin Blaser of Rutgers University.
“Up to now, the complications have been infrequent … however, as the use of FMT is broadened and more compromised patients are treated, complications may be more frequently observed.’
“FMT material includes bacteria, fungi, protozoa, viruses, cytokines, and metabolites. Scientists must determine which of the myriad entities are the salutary agents; the harmful ones will make themselves known,” he warned.
As part of its regulatory approach to FMT, the Therapeutic Goods Administration has announced on 19 September that it is working to develop an appropriate FMT product standard “that will specify the minimal requirements for donor and product screening.”