FDA testing found 5 fungal species, including one known for antifungal resistance, in Neogen Vet HYCOAT, a product labeled as sterile.
Nearly 100 horses developed serious joint infections after receiving a veterinary product that federal testing found was contaminated with multiple fungi, the FDA announced September 29.1 At least 20 of the horses were euthanized after treatment failed.
The product, Neogen Vet HYCOAT, is a hyaluronate sodium sterile solution manufactured for Neogen Corporation, a Lansing, Michigan-based company, by a contract manufacturer. It is labeled for topical wound management, including surgical wounds and burns, but veterinarians also commonly inject the product into joints, according to the FDA.
FDA testing found 5 fungal species in one lot, including Purpureocillium lilacinum, which the agency said is particularly resistant to antifungal drugs.
“P. lilacinum is particularly resistant to antifungal drugs, making infections caused by this organism especially difficult to treat,” the FDA said in the September 29 announcement.1
According to the agency, deaths among the affected horses represent the highest number associated with a quality defect in an FDA-regulated veterinary medical product. They also mark the highest number of animal deaths linked to microbiological contamination of a product labeled as sterile.1
Even so, the number of deaths could be higher. The FDA's fatality count includes only deaths reported to the agency, while its count of affected horses includes only reports containing enough identifying information for the agency to determine that individual animals were involved. The agency said it has not been told the final outcome for many of the horses involved. In a September 23 warning letter to Neogen Corporation, the federal agency said epidemiological and clinical evidence tied the product to more than 95 individual cases.2
The FDA's investigation began after veterinarians reported adverse events involving horses that had received HYCOAT by intra-articular injection in late 2025.
The product is packaged in a glass vial with a septum top, a format commonly used for sterile injectable drugs. The agency said Neogen did not proactively report the adverse events.
The voluntary reports from veterinarians prompted the FDA's investigation, which included testing HYCOAT and inspecting the facility where the product was manufactured.1,2
The FDA tested lot 5A001 and found viable fungi from five species: Purpureocillium lilacinum, Paraisaria heteropoda, Gongronella lacrispora, Purpureocillium sodanum and Isaria takamizusanensis.
Fungi introduced into a joint can cause infection, tissue destruction, and systemic illness.
“Injection of microbiologically contaminated HYCOAT into the joint space and surrounding joint structures can cause painful lameness due to severe inflammation and infection in the joint tissues, resulting in euthanasia of some patients, particularly if the infection is refractory to treatment,” the FDA wrote in its letter to Neogen.2
The product also poses risks when used as labeled, the FDA said. Fungal contamination introduced into an open wound can enter the bloodstream and cause infection, cellulitis, tissue necrosis, and sepsis.
FDA inspectors also found that HYCOAT was being produced under conditions the agency considered unsuitable for manufacturing a sterile product at the contract manufacturer's facility. The facility was described as a cleanroom located inside a warehouse.2
According to the FDA, the facility did not use a sporicidal agent to clean the manufacturing environment or monitor differential pressure and viable particulate levels. Personnel were not sampled for viable microorganisms, and the company had not conducted smoke studies to evaluate airflow in the ISO 5 area.
Gowning practices left portions of employees' skin exposed, nonsterile components were used, and media fills did not simulate worst-case manufacturing scenarios.2
The FDA said Neogen had failed to exercise adequate quality oversight of the contract manufacturer and remained responsible for the product because it was distributed under the company's label.2
The warning letter included photographs from the inspection.
“Although we note the site was not in production at the time these photographs were taken, they demonstrate the obvious uncleanliness and unsuitability of the site for producing a sterile product, which you could have easily discovered and acted upon,” the FDA wrote in its warning letter.2
The FDA determined that HYCOAT was adulterated and misbranded under the Federal Food, Drug, and Cosmetic Act because of microbial contamination and manufacturing conditions that did not meet applicable requirements.
Neogen voluntarily recalled all lots of HYCOAT within their expiration dates on January 28, 2026, citing microbial contamination in certain lots of the 10 mL/50 mg product. The company also recalled the 2 mL/20 mg product as a precaution. The product is labeled for use in dogs, cats, and horses and had been distributed nationwide.3
Neogen Vet HYCOAT is packaged in 2 mL/20 mg and 10 mL/50 mg vials. The recalled lots within their expiration dates include:
2 mL/20 mg
UPC: 726087089386
Lot numbers: 0236735, 0236736, 0336746, 0336747, 0536760, 0536761, 0636768, 0636769, 0836792, 0836785, 0836788, 0836789, 0936794, 0936795, 1036801, 1036802, 1036803, 1036804, 1136807, 1136808, 0246837, 0246838, 4L001B, 4L002
10 mL/50 mg
UPC: 726087089393
Lot numbers: 0136731, 0736777, 0346843, 5A001
In its recall announcement, Neogen said the adverse events involved horses that received HYCOAT by intra-articular injection. The company said it had not received reports of adverse events when the product was used in a manner consistent with its labeling.3
The FDA gave Neogen 15 working days to respond to the September 23 warning letter and describe the corrective actions the company has taken or plans to take.2
The agency also issued a warning letter to Sciarra Aeromed Inc., the contract manufacturer identified in the FDA's investigation.2
dvm360 contacted Neogen for comment on the FDA's warning letter and the company's plans for HYCOAT. The company did not respond to requests for comment by publication time.
The FDA urged veterinarians to report adverse events and product-quality concerns involving HYCOAT and other veterinary products. Reports can be submitted to the FDA's Center for Veterinary Medicine using Form FDA 1932a.
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