Researchers have looked at the burden of Salmonella in children in Portugal to help improve knowledge of the pathogen in the country.

The study aimed to characterize, from an epidemiological, microbiological, and clinical perspective, cases of Salmonella among children.

In Portugal, from 2011 to 2014, 785 Salmonella infections were reported with more than 80 percent in children younger than 15 years of age.

Researchers looked at salmonellosis at a hospital in Lisbon between January 2015 and July 2020. This included 63 children, of which 81 percent were Portuguese. Thirty-six cases were male, according to the study published in the journal Acta Médica Portuguesa (AMP).

The median age at diagnosis was 4 years old but ranged from 3.5 to 9. The under-5 age group had the most cases. Despite the small number of cases per year, 37 were severe enough to require hospitalization.

There was a median of 11 cases per year in the study period, with a variation from 14 in 2015 and 2017 to six in 2018. The number of patients was likely much higher because of a lack of medical treatment in many cases. The months of May, June, and September had the highest number of patients.

Growing evidence base
When the serotype was identified it was mainly Salmonella Enteritidis or Salmonella Typhimurium.

“It is presumed that the prevalence of salmonellosis is much higher than the one presented. One of the reasons is that, although notification in our country for all Salmonella infections is mandatory, many cases are not recognized during the initial assessment and therefore, are not notified,” said researchers.

“Moreover, not everyone who has a Salmonella infection seeks medical care, and healthcare providers may not obtain a specimen for laboratory diagnosis, or the clinical diagnostic laboratory may not be able to perform the necessary diagnostic tests.”

Scientists said findings would expand knowledge on salmonellosis in Portugal and improve prevention strategies, treatment, and its reporting.

Data on consumption of potentially contaminated food was scarce but of 12 children, two were confirmed to have had milk and eggs. Concerning recent trips, data were available for 17 children: two each had been to Guinea-Bissau or Angola and the others had traveled to São Tomé and Príncipe, Brazil, India, and Morocco.

“Preventing contamination implies control at all stages of the food chain: specific measurements in primary production, namely the control of animal feed and compliance with good hygiene practices in animal production and processing, to avoid cross-contamination; storage temperature control so that growth is prevented; and particular attention to products that undergo reformulation, since it favors the growth of Salmonella,” according to the study.

There were complications in 24 children, with dehydration being the most frequent. Out of children whose medical follow-up was known, 12 collected new stool samples were negative, on average, 3.5 months after the diagnosis.

Antibiotic resistance rates were 19 percent for ampicillin and 6.4 percent for amoxicillin-clavulanate and cotrimoxazole. No resistance to third-generation cephalosporins was found. The highest rates of resistance were identified in Salmonella Typhimurium to ampicillin.

Researchers said a national study should be done to ascertain the real incidence of salmonellosis in Portugal, as well as the most frequent strains and antibiotic resistance. They added that the notification rate, although mandatory, remains below expectations.