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Cronobacter Illness and Infant Formula

Learn About Cronobacter Infection

Cronobacter: A group of bacteria found in the environment and foods

Photo: Cronobacter bacteria growing in a laboratory

Cronobacter bacteria growing in a laboratory

Cronobacter (formerly called Enterobacter sakazakii) is a group of bacteria that are found naturally in the environment. These bacteria can survive in very dry conditions. Sometimes, they have been found in dry foods, such as powdered infant formula, powdered milk, herbal teas, and starches. They also have been found in wastewater. It is likely Cronobacter bacteria can be found in other places, too.

Rare, but serious illness in infants

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.With recent increased awareness of Cronobacter illness in infants, CDC was informed of a total of 13 cases in 2011. 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 most likely to develop meningitis if they are infected with Cronobacter bacteria. Infants born prematurely and those with weakened immune systems are also at increased risk for serious Cronobacter infections.

Photo: A father bottle feeding an infantIn 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.

Not just infants

Cronobacter bacteria can also cause diarrhea, wound infections, and urinary tract infections in people of all ages. The elderly and people with weakened immune systems (for example, people being treated with immune-suppressing drugs for cancer, organ transplants, or other illnesses, or those with HIV infection or genetic conditions that affect the immune system) are most at risk.

Illnesses linked to powdered infant formula

In some outbreak investigations, Cronobacter bacteria were found in powdered infant formula that had been contaminated in the factory. In other cases, Cronobacter bacteria might have contaminated the powdered infant formula after it was opened at home or elsewhere during preparation.

Since the bacteria live in the environment, it's likely there have been other sources of this rare disease.

Powdered infant formula is not sterile

Manufacturers report that, using current methods, it is not possible to eliminate all germs from powdered infant formula in the factory. Powdered infant formula can also be contaminated after the containers are opened. Very young infants, infants born prematurely, and infants with weakened immune systems are at the highest risk.

Photo: A mother breastfeeding a infant.To best protect your infant, here are some things you can do:

  • Breastfeed. Breastfeeding helps prevent many kinds of infections among infants. Almost no cases of Cronobacter infection have been reported among infants who were being exclusively breastfed (meaning, the baby was fed only breast milk and no formula or other foods).
  • If your baby gets formula, choose infant formula sold in liquid form, especially when your baby is a newborn or very young. Liquid formulations of infant formula are made to be sterile and should not transmit Cronobacter infection.
  • If your baby gets powdered infant formula, follow these steps
    If your baby gets 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. These are keys to keeping your baby safe and healthy.
    • Clean up before preparation
      • Wash your hands with soap and water
      • Clean bottles in a dishwasher with hot water and a heated drying cycle, or scrub bottles in hot, soapy water and then sterilize them
      • Clean work surfaces, such as countertops and sinks
    • Prepare safely
      • Keep powdered formula lids and scoops clean (be careful about what they touch)
      • Close containers of infant formula or bottled water as soon as possible
      • Use hot water (158 degrees F/70 degrees C and above) to make formula
      • Carefully shake, rather than stir, formula in the bottle
      • Cool formula to ensure it is not too hot before feeding your baby by running the prepared, capped bottle under cool water or placing it into an ice bath, taking care to keep the cooling water from getting into the bottle or on the nipple
      • Before feeding the baby, test the temperature by shaking a few drops on your wrist
    • Use up quickly or store safely
      • Use formula within 2 hours of preparation. If the baby does not finish the entire bottle of formula, discard the unused formula.
      • If you do not plan to use the prepared formula right away, refrigerate it immediately and use it within 24 hours. Refrigeration slows bacterial growth and increases safety.
      • When in doubt, throw it out. If you can't remember how long you have kept formula in the refrigerator, it is safer to throw it out than to feed it to your baby.
  • Photo: Washing handsPractice proper hygiene
    • Wash your hands carefully with soap and water, especially after using the toilet or changing diapers. Always wash your hands:
      • before preparing and feeding bottles or foods to your infant
      • before touching your infant's mouth, and
      • before touching pacifiers or other things that go into your infant's mouth.
    • If soap and water aren't available, use an alcohol-based hand sanitizer. These alcohol-based products can quickly reduce the number of germs on hands in some situations, but they are not a substitute for washing with soap and water.
    • It is also important to keep all objects that enter infants' mouths (such as pacifiers and teethers) clean.

More Information

Cronobacter publications:

Food Safety and Handwashing:

Breastfeeding:

CDC works 24/7 saving lives and protecting people from health threats to have a more secure nation. A US federal agency, CDC helps make the healthy choice the easy choice by putting science and prevention into action. CDC works to help people live longer, healthier and more productive lives.

  • Page last reviewed: January 11, 2012
  • Page last updated: April 6, 2012
  • Content source:
    • Office of the Associate Director for Communication, Digital Media Branch, Division of Public Affairs
    • Page maintained by: Office of the Associate Director for Communication, Digital Media Branch, Division of Public Affairs
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