Indian drug regulators on Saturday ordered Tamil Nadu-based Global Pharma Healthcare to stop the production of its ophthalmic formulations, two days after the US authorities linked the firm’s eye drops to bacterial infections, vision loss and one death.

The order follows a joint investigation in which drug inspectors from the Central Drugs Standard Control Organisation (CDSCO) and Tamil Nadu state drug authority visited the firm’s facilities in Kancheepuram on Friday, officials said.

The US Food and Drug Administration (FDA) had issued an alert on Thursday asking consumers and healthcare practitioners not to purchase and to immediately discontinue using Ezricare Artificial Tears made by Global Pharma Healthcare, citing potential bacterial contamination.

The investigation at the Global Pharma Healthcare’s facilities in Kancheepuram has confirmed that the firm had exported to the US two consignments of 24 batches of Artificial Tears manufactured during 2021 and 2022, Indian officials said.

The inspections found no stocks from the exported batches. However the inspectors picked up control samples — a sample that manufacturers are mandated to keep for every batch produced — from four batches for analysis, the officials said.

The inspectors have also collected for analysis the raw material — carboxy methyl cellulose sodium — used in the production of the artificial tears. The firm has told the inspectors that a “root cause analysis” of the complaint is underway.

A root cause analysis is a process to determine the source of a problem.

The FDA and the US Centres for Disease Control and Prevention (CDC) are currently investigating an outbreak of infections caused by a rare drug-resistant bacterial strain in 12 US states. The investigation has identified 55 patients, many of whom had used the eye drops, with the bacterial infection.

The CDC said earlier this week that lab tests had identified the bacterial strain in opened bottles from two states, but more studies are underway to determine whether the contamination may have occurred during manufacturing.

The affected patients in the US had turned up with eye infections, respiratory infections or urinary tract infections. Some patients suffered from vision loss, resulting from corneal infection and one patient had died after systemic infection.

The alert from the US is the third since October in which foreign health authorities have raised quality concerns about drugs from India. Authorities in the Gambia and Uzbekistan have linked child deaths to cough syrups from India contaminated with toxic chemicals.