Researchers from the CDC, FDA, and seven state health departments report that news in Pediatrics. The scientists included Timothy Jones, MD, of Tennessee's health department.
The study looked at 442 infants in eight states diagnosed with salmonella infection before their first birthday.
There are different types of salmonella bacteria; Jones' team focused on nontyphoidal salmonella not linked to an outbreak.
The babies' most common symptoms were diarrhea and fever. They typically recovered within a week; however, two babies died as a result of their infection.
The babies' parents completed extensive questionnaires about their child's animal exposure, food, and drink in the five days before salmonella infection.
For comparison, the researchers gave similar questionnaires to parents of 928 babies the same age who were not affected by the bacteria.
The interviews showed six key differences between babies who got salmonella infection and those who didn't.
1. Breastfed babies were less likely to get salmonella infection. The reason for that isn't clear, but Jones' team says other studies have shown similar results.
2. Exposure to reptiles upped babies' chance of infection. Reptiles can carry salmonella. The CDC recommends that homes with kids under 5 years old not include reptiles.
3. Babies who rode in a shopping cart next to meat or poultry were more likely to get infected. Putting meat and poultry in a part of the cart away from kids might help; so might better packaging, the researchers note.
4. Babies over 3 months old who traveled outside the U.S. were more likely to get infected.
5. Babies who drank concentrated liquid infant formula were more likely to get salmonella infection.
The reason for that isn't clear. Concentrated formula is sterile, but tainted water, unhygienic preparation, or poor storage of opened cans might be a problem, say the researchers.
Salmonella infection wasn't linked to ready-to-drink liquid infant formula or powdered infant formula.
6. Babies older than 6 months were more likely to get salmonella infection if they attended day care with a child who had diarrhea.
More studies are needed to make recommendations about salmonella prevention in babies, write the researchers.
SOURCES: Jones, T. Pediatrics, December 2006; vol 118: pp 2380-2387. News release, American Academy of Pediatrics.
By Miranda Hitti
Reviewed by Louise Chang