Federal health officials are warning parents of newborns to sterilize equipment used for both bottle- and breast-feeding after a baby died last year from a rare infection tied to a contaminated breast pump.

The infant, a premature boy, was infected with the bacteria Cronobacter sakazakii, the same germ that sparked a recall and nationwide shortage of powdered infant formula last year, according to a Centers for Disease Control and Prevention report released today.

But this baby’s infection was not caused by contaminated formula.

The child, who was hospitalized, had been fed a mix of breastmilk and liquid human milk fortifier through a tube. Genetic sequencing linked the infection to bacteria isolated from a breast pump used at home. Samples from expressed milk, a breast pump used in the hospital and the liquid human milk fortifier were all negative for the bacteria.

An investigation found that the home breast pump was cleaned in a household sink, sanitized and sometimes assembled while still moist.

Dr. Julia Haston, a CDC expert in pediatric infectious diseases, said the case underscores that cronobacter bacteria are found widely in the environment and can lead to severe and deadly infections.

“There are steps that people can take to prevent infections,” she said, including thoroughly washing, sanitizing and drying hands, equipment and all surfaces before feeding a baby.