All had been given an intravenous nutritional product manufactured by an Alabama company, which recalled all of its products following the outbreak.
But an Alabama health official warned the outbreak's origin remained unclear.
'Contained' The stricken patients at six Alabama hospitals were all taking an intravenous nutritional product manufactured by a single pharmacy, Meds IV, the state Department of Public Health said in a Tuesday statement.
Upon learning of the outbreak, the company ceased production and on 24 March recalled all of its intravenous products, the department said.
"We're not expecting any additional cases," Dr Mary McIntyre, of the department's bureau of communicable disease, told the BBC. "It has been contained."
But she cautioned that investigators had not directly linked the outbreak to the nutritional product, called TPN (total parenteral nutrition).
She said the federal Centers for Disease Control and Prevention, and the Food and Drug Administration had joined state authorities in the investigation.
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