Nearly 5,700 listeriosis-related hospitalizations occurred in Spain in less than 20 years, according to researchers.

Results suggest an increasing trend of listeriosis infection and hospitalization rates in Spain during the study period. In the past decade, incidence rates have increased or remained at relatively high levels across Europe. The study, published in the journal Eurosurveillance, provides a 19-year review of listeriosis hospitalizations in Spain.

Between 1997 and 2015, there were 5,696 hospitalizations with a diagnosis of listeriosis recorded in the centralized hospital discharge database (CMBD) database and almost a fifth of the patients died. Mean age of the hospitalized patients was 58.6 years and 59 percent were male.

Spain’s high Listeria rate
Before 2015, when it was added to the list of mandatory notifiable diseases, regions could voluntarily report listeriosis to the Microbiological Information System (SIM).

“As demonstrated in the Netherlands, public health investment in surveillance can yield an increase in reported cases of listeriosis; therefore, an increase in listeriosis detection may be expected in the future,” according to the study.

The increasing proportion of susceptible people in the general population and rise in consumption of ready to eat foods could be contributing factors to increased incidence.

From 2009 to 2013, there were 588 listeriosis cases reported to SIM, the European Surveillance System (TESSy) and yearly European Food Safety Authority (EFSA) reports; however, 2,051 listeriosis-related hospitalizations were recorded in the CMBD, indicating under-reporting.

“Even if this indicates that the epidemiological scenario is quite uncertain, in 2012 the Spanish listeriosis rate reported to EFSA was the second highest of any country in the European Union (0.93, vs an EU-wide incidence rate of 0.41/100,000 population); this indicates that more attention needs to be given to preventing and controlling this disease in Spain,” said researchers.

The CMBD database receives notifications from around 98 percent of the public hospitals in Spain. It does not provide information about the laboratory tests used for listeriosis diagnosis and mother-baby pairs could not be identified due to data protection reasons.

During the study period, only a few listeriosis outbreaks were reported, mostly in the Basque country. They were related to Latin-style fresh cheese made from pasteurized milk in Portugal and cooked ham.

Researchers found higher hospitalization rates mostly in the north of the country. Catalonia had the highest incidence rates, followed by Cantabria, Rioja, Basque country, and Galicia.

“This might be due to differences in dietary habits, food consumption or regulations; the population’s average age; differences in educational preventive measures and/or that health professionals are more prone to seek listeriosis diagnosis,” they said.

Advice during pregnancy
Age was categorized in four groups: 15 and younger; 16-44; 45-64; and 65 and older. The  65 and older group showed the highest hospitalization rate, followed by 45 to 64 year olds.

Males predominated in the age groups 45 to 64 years old at 68.1 percent and 65 and older at 63 percent, while females represented 64.6 percent of those 15 to 44 years old, which is thought to reflect pregnancy‐related listeriosis.

“In Spain, there is currently no screening for listeriosis during pregnancy, nor specific dietary recommendations for pregnant women; therefore, dietary recommendations and screening activities during pregnancy should be introduced,” according to the study.

Average length of hospital stay for listeriosis was 21.4 days. Hospitalization costs ranged with a median value of €6,327 ($7,000) per case and no significant changes over time.

Fatal outcome occurred in 17 percent of all listeriosis hospitalizations. Patients aged 65 and older accounted for 67.5 percent of deaths.

Pregnant women accounted for 396 hospitalizations. No fatal outcomes were registered. Neonatal infections represented 225 overall hospitalizations. Fatal outcome was less frequent in infected neonates than the overall population at 8.9 percent vs 17.3 percent.

Underlying immunocompromising conditions were observed in 3,213 out of 5,696 of the hospitalized patients with causes for the patients’ weakened systems related to malignant neoplasm, diabetes, chronic liver disease, HIV infection and other issues.

Researchers said hospital records underestimate the real burden of listeriosis in Spain and the public health problem needs to be prioritized due to the increasing trend and severity.

“Listeriosis surveillance needs to be improved and further targeted prevention is urgently needed, including food safety education and messaging in all at-risk groups. Furthermore, industrial and regulatory measures needs to be implemented in parallel, as an integrated and multi-sectoral approach is the only way to successfully prevent and control listeriosis.”

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