Research shows that Listeria is on the rise in Spain

The number of patients hospitalized with Listeria monocytogenes in Spain has increased significantly since 2000.

Researchers said the findings should raise concerns about the health burden of listeriosis, especially in the elderly and people with weakened immune systems.

Data on hospital admissions with Listeria monocytogenes from 2000 to 2021 were obtained from the Spanish National Hospital Discharge Database. In 2015, the Spanish government declared listeriosis a mandatory notifiable disease.

A study in the International Journal of Infectious Diseases shows that between 2000 and 2021, there were 8,152 hospital admissions diagnosed with Listeria monocytogenes. The average length of stay was 20.5 days and the average age was 59.5 years old.

4,747 were men, 540 were pregnant women and 3,196 were immunosuppressed patients. The in-hospital mortality rate for patients with listeriosis during the study period was 16.7 percent.

Impact of COVID-19 and major outbreak

Listeria monocytogenes admissions have increased significantly, from 5 admissions per 1 million inhabitants in 2000 to 8.9 in 2021. However, they declined in 2020 due to measures to control the COVID-19 pandemic.

In 2019, a large increase in both incidence and mortality was observed, which was associated with the largest outbreak of listeriosis in Europe. It happened in Andalusia and was linked to the consumption of stuffed pork from a producer called Magrudis. A total of 207 microbiologically confirmed patients and more than 3,000 suspected cases were detected. Three people over 70 years old died.

In the study, the number of deaths due to Listeria monocytogenes increased from 7.8 per 100,000 deaths in 2000 to 18 per 100,000 deaths in 2021.

Age over 65 years, sepsis, meningoencephalitis, endocarditis, neonatal listeriosis and immunosuppression were all independently associated with death.

Research revealed a growing impact of Listeria monocytogenes on the most vulnerable patients. Similar trends have been observed in other countries.

Scientists say the increase in hospitalizations and deaths over time in patients with Listeria monocytogenes was mainly driven by the increased proportion of elderly and immunosuppressed patients.

“Our findings raise concerns about the health burden of listeriosis in Spain. Despite the Spanish Ministry of Health declaring a mandatory notifiable disease in 2015, our analysis of hospital admissions shows that far from improving, the numbers are actually worsening,” they say.

“Specific programs aimed at surveillance and prevention of human listeriosis are warranted. Additional measures should be taken to prevent foodborne infections and outbreaks from animal reservoirs.”

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