FDA Warning Letter for a microbially contaminated Sterile Solution

Not as the result of an inspection, but due to more than 95 incidents caused by a microbially contaminated sterile solution, the FDA issued a Warning Letter to a US-based veterinary manufacturer.

According to the FDA, product samples were collected, the manufacturing facility was inspected, and epidemiological and clinical evidence from the more than 95 individual cases was evaluated. As stated by the FDA, this contamination led to the highest number of deaths ever recorded for a single animal species in connection with a sterile product regulated by the FDA for veterinary use. The manufacturer subsequently recalled several batches of potentially contaminated sterile sodium hyaluronate solution in January 2026, which had been produced by a contract manufacturer.

The FDA found that the product labelled as a "sterile solution" was in fact not sterile. Several viable microbial organisms were detected, including the fungal species Purpureocillium lilacinum, Paraisaria heteropoda, Gongronella lacrispora, Purpureocillium sodanum and Isaria takamizusanensis. The FDA also addresses an off-label use as a joint injection and the lack of adequate instructions for use. Injecting a microbially contaminated product into a joint space can lead to severe inflammation and infection. According to the FDA, animals had to be euthanised in individual cases.

The inspection subsequently carried out at the contract manufacturer revealed unhygienic conditions. The FDA cites the following examples:

• Inadequate cleaning and disinfection of the manufacturing environment (no use of a sporicidal agent)
• Inadequate monitoring of differential pressures
• Inadequate environmental monitoring (no sampling for viable particles or microorganisms)
• No personnel monitoring for viable microorganisms
• No smoke studies to demonstrate airflow in the ISO 5 area
• Poor structural condition and maintenance (cleanroom in a warehouse-style setting, several examples of uncleanliness and "state of disrepair")
• Inadequate gowning (exposed skin, non-sterile clothing components)
• Inadequate media fills, as these did not reflect real production

The FDA states that the company did not exercise adequate quality oversight over the contract manufacturer.

On the FDA website you will find the full Warning Letter.