A study investigating pregnancy-related listeriosis cases found a more widespread outbreak in Italy.
In January 2020, a 28-year-old pregnant woman from a city near Rome was admitted to a hospital in Rome.
A caesarean section was performed and a girl was born. The baby had trouble breathing and was diagnosed with hyaline disease. A blood culture sample taken several hours after birth showed growth of Listeria monocytogenes. She was transferred to the neonatal intensive care unit for her 24-hour invasive ventilation. Baby she was discharged one month later in good clinical condition.
After being notified of a case of listeriosis, a survey by local health authorities administered an epidemiological questionnaire to mothers to assess potential food exposures during the 30 days prior to the onset of illness.
Based on responses, the health agency’s attention focused on fresh horse meat purchased from a local butcher and cold cuts from the deli counter purchased from one of two supermarkets.
Additional investigations found three more cases between May 2019 and May 2020. The first case involved a patient admitted to the emergency department. A second patient, she was admitted in April 2020. The third patient, she occurred in May 2020. One patient was identified as going to the same supermarket as the mother of a newborn with listeriosis, says a study published in Pathogens.
contaminated equipment
The outbreak was associated with consumption of ready-to-eat sliced products sold in supermarkets.
A sample of a large Italian sausage called mortadella from one of the supermarkets tested was positive for Listeria monocytogenes. It was also a cold food counter where cold cuts were commonly served.
Investigations suggested that the source was active for an extended period of time before and after official inspection by local health authorities. After sanitation of the facility, self-control and health unit sampling were negative, and the deli counter was reopened.
Contaminated food spread the infection from mother to baby. Studies have shown that maternal gastrointestinal symptoms were probably confused with labor contractions.
The Listeria monocytogenes strain behind the incident appears to be uncommon in this country and confined to central Italy, mainly Lazio.
Researchers say continued education about dietary precautions for pregnant women is needed to reduce the incidence of listeriosis.
“This study highlights the importance of constant foodborne disease surveillance, from notification to investigation, conducted by health authorities in collaboration with clinicians and researchers. The goal is to identify and contain them as early as possible to avoid spreading foodborne outbreaks,” the researchers wrote.
Investigation of food poisoning in two regions
Meanwhile, another study published in Toxins details a three-year foodborne infection investigation involving the Food Microbiology Unit of the Istituto Zooprofilattico Sperimentale del Lazio e della Toscana (IZSLT) in Italy.
There were 13 investigations in 2020, compared to 28 and 29 in 2018 and 2019. Researchers say the COVID-19 pandemic is likely behind the decline.
Data from 70 food-derived studies were analyzed. In total, 19 of the 340 food samples were positive for bacterial pathogens, toxins, or both. Of the positives, more than half involved meat-based products. The samples under study were mainly collected by authorities in Lazio and Tuscany. The top pathogen detected was Listeria monocytogenes. Found 6 times.
Of the 70 investigations, only 17 followed formal foodborne illness reports by health systems where the patient had a clinical diagnosis. Of the remaining cases, 29 began with direct consumer reports after the onset of symptoms, and 24 were reported by authorities without information about the patient’s condition.
“Despite the serious impact foodborne diseases have on human health and the economy, many foodborne disease investigations fail to identify the source of infection. It demonstrates the need to continue to develop and implement fully integrated healthcare networks,” said the researchers.
(To sign up for a free subscription to Food Safety News, click here.)