WASHINGTON - At least 14 Americans have been killed, 156 others sickened in a deadly fungal meningitis outbreak linked to contaminated drug, the US Centers for Disease Control and Prevention (CDC) reported Thursday.

The outbreak has claimed lives in six states - Tennessee, Michigan, Maryland, Virginia, Florida and Indiana, the CDC said in its latest update. Tennessee remained the hardest-hit state with 49 cases; Michigan added 11 cases and was at 39 on Thursday, with Virginia adding three to reach 30 and Indiana six to reach 21.

Public health officials were contacting patients in 23 states who received the potentially contaminated steroid injection - typically for back pain - and urging them to be tested for the rare fungal infection. The CDC said some 14,000 patients could be at risk of contracting meningitis.

The Food and Drug Administration said it has detected a fungal contaminant in a sealed vial of the drug produced by the New England Compounding Center. While further testing is required to confirm it was the source of the outbreak, the company has issued a recall of all of its products and shut down all operations.