Background: The unapproved and unregulated use of umbilical stem-cell products has been identified as a possible source of adverse events and infection. In 2018, a national outbreak of multiple bacterial infections was associated with use of umbilical stem cells products. From December 2018 through March 2019, the Los Angeles County Department of Public Health (LACDPH) identified 4 cases of bacterial infection in patients that had received therapies using umbilical stem-cell products. Although 2 cases were associated with the national outbreak of a single company’s product, 2 additional cases of Enterobacter cloacae were instead associated with a second stem-cell distributer. Methods: In December 2018, LACDPH staff received notification from a hospital infectious disease physician of 2 cases of E. cloacae infection in patients of a freestanding ambulatory surgery center following allogenic umbilical cord stem-cell injections on the same day in August 2018. LACDPH reviewed the medical records of these patients and conducted an on-site visit to the ambulatory surgery center, which included observation of infection prevention practices, interview of staff, and review of logs. The 2 isolates from each patient were sent to the CDC laboratory for relatedness testing. Results: The 2 case patients received products via intra-articular injection from different lot and donor numbers for lumbar spine pain. In addition to the stem-cell product, both patients also received antibiotics and pain medications during their procedures, though from different vials. Both patients were seen by the same surgeon, anesthesiologist, and nurse during their procedures. No additional cases occurred. The case patients were hospitalized for 12 and 27 days, respectively. Whole-genome sequencing indicated that the isolates from the 2 patients were related. No major gaps in infection prevention practices were identified at the surgery center. Conclusion: This report describes a cluster of 2 E. cloacae infections in patients who had received unapproved-use stem-cell products via spinal injection. Given molecular laboratory results and infection prevention observations, we hypothesize that the stem-cell products used on these 2 cases were likely contaminated before distribution. This cluster demonstrates that contamination of stem-cell products extends beyond the single outbreak previously described and points to the systematic inability to ensure the safety of unapproved use of umbilical stem- cell products.

Funding: None

Disclosures: None