Cronobacter is a type of bacteria that can cause serious infections, particularly in infants. While infections are uncommon, they can lead to severe illness. Understanding this bacterium, its presence in the environment, and how to prevent its spread is important for public health.
Understanding Cronobacter
Cronobacter is a genus of bacteria, with Cronobacter sakazakii being the species most frequently associated with human illness. This bacterium is gram-negative, rod-shaped, and can survive in very dry conditions.
These bacteria are naturally present in the environment, including on plants and organic materials. They are known for their ability to persist in low-moisture, dry foods due to features like a protective capsule and acid tolerance.
Sources and Transmission
Cronobacter bacteria are found widely in the environment, including in dust, water, and on various surfaces in homes and food processing facilities. They can live in dry foods like powdered infant formula, powdered milk, herbal teas, and starches. Contamination can occur during manufacturing or after a product is opened.
Powdered infant formula is not sterile; manufacturers acknowledge it’s not possible to eliminate all germs during production. Contamination can happen if ingredients are tainted or formula touches a contaminated surface in the facility.
In the home, Cronobacter can transfer to powdered formula from contaminated surfaces like kitchen counters or sinks, via lids or scoops. Contaminated feeding items, like breast pump equipment, can also harbor the bacteria. Transmission primarily occurs orally, often via contaminated food.
Vulnerable Populations and Health Impacts
While Cronobacter infections are rare, they can be particularly dangerous for certain groups, especially infants. Infants less than two months old are at the highest risk for severe illness, including meningitis, an inflammation of the membranes protecting the brain and spinal cord. Premature infants, those with low birth weight, and infants with weakened immune systems are also highly susceptible.
Infections in infants can lead to severe conditions such as sepsis, which is a dangerous bloodstream infection, and necrotizing enterocolitis (NEC), a serious intestinal disease. NEC inflames intestinal tissue, potentially causing tissue death.
Symptoms in infants often appear as fever, poor feeding, excessive crying, or very low energy. Infants developing meningitis may also show signs like seizures, grunting breaths, or abnormal body movements. While less common, Cronobacter can also cause infections in older children and adults, leading to wound or urinary tract infections. Immunocompromised adults and those over 65 years old may also be at risk for bloodstream infections.
Risk Reduction and Prevention
Preventing Cronobacter infection, particularly in infants, involves strict hygiene practices during food preparation. Breastfeeding is encouraged as very few Cronobacter infections have been reported in infants fed only breast milk. For those using powdered infant formula, selecting sterile liquid formula when possible can reduce risk, as powdered formula is not sterile.
When preparing powdered infant formula, caregivers should wash their hands thoroughly with soap and water before beginning. All feeding items, including bottles, nipples, and breast pump parts, should be cleaned and sanitized properly. This involves washing in a dishwasher with hot water and a heated drying cycle, or by hand in hot, soapy water, then air drying on a clean rack. Avoid placing feeding items directly in sinks, as drain germs can contaminate them.
For infants at higher risk (under two months old, premature, or with weakened immune systems), extra precautions are recommended when preparing powdered formula.
- Use water heated to at least 158°F (70°C) to prepare the formula.
- Boil water and allow it to cool for no more than 30 minutes to reach this temperature.
- Use prepared formula within one hour of starting a feeding and within two hours of preparation; discard any leftover.
- Refrigerated formula should be used within 24 hours.
- Keep powdered formula containers dry, close them quickly after use, and avoid getting the scoop wet.