ATLANTA – Pregnant women and adults aged 65 and older face the highest risk fromListeriathan most other bacteria commonly spread by contaminated food, according to Centers for Disease Control and Prevention.

Adults aged 65 years and older are four times more likely to getListeriainfection compared to the general US population, CDC said, while pregnant women are 10 times more likely to contract infection. Hispanic women are 24 times more likely to getListeriainfection, the agency said.

"These groups — along with newborns and people with other health conditions that weaken their immune systems — account for at least 90 percent of reportedListeriainfections," CDC said in its Vital Signs report.

Listeriastrikes hard at pregnant women, the elderly, and people with weakened immune systems, sending many to the hospital and causing miscarriage or death in as many as one in five,” said Tom Frieden, M.D., M.P.H., director, CDC. “We need to develop new cutting edge molecular technologies to help us link illnesses and outbreaks to foods faster to prevent illness and death, which is why the President’s budget proposes investing in new tools to advance this work.”

The CDC also reported:

• More than 1,650 cases of Listeria infections are reported to the CDC over a three-year period.
• About 20 percent of infections resulted in death, primarily among older people and as miscarriages or stillbirths. Pregnant women who have Listeria infections often have only mild symptoms or fever, but illness may result in miscarriage, premature labor and serious illness or death in newborn infants.
• Over three years, twelve outbreaks sickened 224 patients in 38 states. These include the large 2011 outbreak linked to whole cantaloupes from one farm.
• Of the 10 outbreaks with an identified food source, six were linked to soft cheese (mostly Mexican-style cheeses) and two to raw produce (whole cantaloupe and pre-cut celery).

Advances in genetic fingerprinting ofListeriathrough CDC’s PulseNet have helped trace manyListeriaoutbreaks, the agency said. The developments led the food industry and regulatory authorities to make changes that improved the safety of foods such as hot dogs and deli meat. CDC said rates ofListeriainfections declined by about 25 percent by the early 2000s, although rates have since leveled off.

Earlier this year, the US Department of Agriculture's Food Safety and Inspection Service and the Food and Drug Administration collaborated on a study that analyzed nearly 27,000 ready-to-eat food samples from retailers to determine the level ofListeriain them. The agencies also made recommendations to improve current food handling practices to enhance the food safety of retail deli products.

“The lower rates ofListeriainfection attributed to meat and poultry over the past decade point to the success of prevention-based policies and industry best practices,” said Elisabeth Hagen, M.D., Undersecretary for Food Safety, US Department of Agriculture. “However, important work remains if we hope to continue this momentum. Additional research and continual monitoring of evolving risks will allow us to develop policies that further reduce these illness rates.”