Investigation of Cronobacter Infections

CDC Update: Investigation of Cronobacter Infections Among Infants in the United States

CDC Update: Investigation of Cronobacter Infections Among Infants in the United States

January 13, 2012

CDC, the Food and Drug Administration (FDA), and state health departments are continuing to investigate four recent cases of Cronobacter infection among infants in four States. The information below updates a joint statement issued by CDC and FDA on December 30, 2011.

There remains no evidence that the powdered infant formula or bottled nursery water were contaminated during manufacturing; however, additional testing is under way at CDC and FDA. Additional information about the four infants, and some results from laboratory testing of samples associated with the infants in Illinois and Oklahoma, are noted below.

CDC recommends that consumers be aware of the risks of infections in infants being fed formula. Information about how consumers can reduce the risk of Cronobacter illness for their infants is found here.


Cronobacter growing in a laboratory.



Description of Recent Cronobacter Cases in Infants

Since November 1, 2011, four infants (children under 12 months of age) infected with Cronobacter bacteria have been reported to CDC.

  • Infants resided in four states: Florida, Illinois, Missouri, and Oklahoma
  • One infant was born slightly prematurely, and all four infants became infected during the first five weeks of age
  • Three infants developed meningitis (inflammation of the membranes around the brain and spine), and one had a bloodstream infection
  • Two infants died; two are recovering

No specific exposures common to all four infants have been identified. All infants consumed powdered infant formula; however, they did not all consume the same brand of formula. CDC is not aware of any new cases since mid-December 2011.

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Laboratory Investigations

To better understand whether cases are related, CDC has been performing genetic typing (DNA fingerprinting) of Cronobacter bacteria from the infants when these bacteria were available from the laboratories that isolated them from the infants. As previously reported, the genetic fingerprints of Cronobacter bacteria from the infants in Illinois and Missouri were not identical. Cronobacter bacteria from the infants in Florida and Oklahoma were not available for testing at CDC.

Testing has been performed of opened containers of powdered infant formula and water obtained from the infants’ homes, when available. Results are summarized below:

  • Florida. None of the products given to the infant in Florida were available for testing.
  • Illinois. No Cronobacter bacteria were found in an opened container of powdered infant formula that was fed to the infant in Illinois. Cronobacter bacteria were found in an opened container of bottled nursery water used to prepare the infant formula. To date, the genetic fingerprints of the Cronobacter from the infant and from the water have differed; however, additional testing is underway.
  • Missouri. Cronobacter bacteria were found in an opened container of powdered infant formula, two prepared bottles of powdered infant formula, and an opened bottle of nursery water used to reconstitute the powdered infant formula given to this infant. The genetic fingerprints of the Cronobacter bacteria obtained from the infant, the formula, and the water were indistinguishable from each other. This genetic fingerprint differed from both that of the Cronobacter bacteria from the infant and from that of the bottled water from Illinois.
  • Oklahoma. No Cronobacter bacteria were found in 3 opened cans of powdered infant formula that had been fed to the infant in Oklahoma, or in tap water, which was used to prepare the infant’s formula, obtained from the infant’s home.

Concurrently, FDA has been testing previously unopened containers of powdered infant formula, bottled nursery water, and other items associated with the infants. Initial results from tests associated with the case in Missouri are available here; additional results will be forthcoming.

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Additional Investigation is Ongoing

Additional laboratory testing and epidemiologic analysis is under way at CDC and FDA. FDA is also inspecting facilities that manufacture products which had been used by the infants.

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Clinical Features/Signs and Symptoms

Cronobacter illness is very rare, but it is often deadly in young infants. It usually occurs in the first days or weeks of life. Typically, CDC is informed of about 4-6 cases of Cronobacter illness in infants each year, but reporting isn’t required. In 2011, CDC was informed of a total of 13 cases. Cronobacter bacteria can cause severe blood infections (sepsis) or meningitis (an inflammation of the membranes that protect the brain and spine). Infants 2 months of age and younger are the infants that are most likely to develop meningitis if they are infected with Cronobacter bacteria. Infants born prematurely and those with weakened immune systems are also at risk for severe illness.

In infants, the illness generally starts with fever. It usually includes poor feeding, crying, or listlessness. Young infants with these symptoms should be taken to a doctor. If a Cronobacter infection is diagnosed by a laboratory culture, CDC encourages clinicians and laboratories to inform their local or state health department.

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Consumer Recommendations

Advice to parents and other infant care-givers can be found here. Key points include:

  • Breastfeed. Breastfeeding helps prevent many kinds of infections among infants.
  • If your baby gets formula, choose infant formula sold in liquid form, especially when your baby is a newborn or very young.
  • If your baby is given powdered infant formula there are things you can do to protect your baby from infections – not just Cronobacter infections. Good hygiene, mixing the formula with water hot enough to kill germs, and safely storing formula can prevent growth of Cronobacter bacteria and other germs.
  • Practice proper hygiene.

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More Information:

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