Salmonella top cause of bacteremia among children with sickle cell disease

Key takeaways:

• Salmonella is the top cause of bacteremia in invasive bacterial infections among children with sickle cell disease.
• Streptococcus pneumoniae and Staphylococcus aureus are second and third in terms of frequency.

Salmonella — not Streptococcus pneumoniae — was the top cause of invasive bacterial infections among children with sickle cell disease in five European countries during a recent 6-year period, a study in Pediatrics reported.

One of the researchers said the idea for the study came out of discussions at the annual meeting of the European Society for Pediatric Infectious Diseases in Madrid in 2017.

“We wanted to focus on a subject that was not so much addressed in the literature, namely the updated epidemiology of bacterial disease in children with sickle cell disease,” Jean Gaschignard, MD, PhD, head of the department of pediatrics at Groupe Hospitalier Nord Essonne in Longjumeau, France, and co-author of the study, told Healio.

“In the context of the development of new conjugated pneumococcal vaccines we believed that an update was necessary,” Gaschignard said, referring to the study period, which began after the 13-valent pneumococcal vaccine was approved in Europe in October 2013.

For their retrospective study, Gaschignard and colleagues built the Sickle Cell Disease Pediatric Research About Infections Group, also called SPRING, and assessed cases from 28 medical centers in Belgium, France, Portugal, Spain and the United Kingdom.

“A major achievement of this work was to make the connections between physicians from different European countries, to include a large series of patients,” Gaschignard said.

They defined an invasive bacterial infection as a positive bacterial culture or PCR from a normally sterile fluid, such as blood, cerebrospinal, joint, or pleural fluid and deep surgical specimen.

The network recorded 169 invasive bacterial infections occurring in children with sickle cell disease aged 1 month to 18 years between 2014 and 2019.

They found that Salmonella was responsible for 26% of invasive bacterial infections — the leading cause — followed by Streptococcus pneumoniae (18%) and Staphylococcus aureus (12%). Salmonella resulted in osteoarticular infections in 45% of episodes and primary bacteremia in 23% of episodes, whereas Streptococcus pneumoniae led to meningitis in 88% of episodes and acute chest syndrome in 50% of episodes.

“We were surprised that Streptococcus pneumoniae did not come first as in previous studies but second after Salmonella,” Gaschignard said. “What was also important but was not a surprise is that Streptococcus pneumoniae remained the major cause of death and of severe cases.”

Of the children, 16% had complications from their infection, with two dying due to Streptococcus pneumoniae and one due to Salmonella. Risk factors for a severe invasive bacterial infection included previous infections and a pneumococcal infection.

“This is a key message for pediatricians,” Gaschignard said. “The efforts to diminish the burden of Streptococcus pneumoniae must be continued in two ways: first, an adequate updated vaccination; and second, [with use of] penicillin prophylaxis.”

He added that researchers could examine the impact of new pneumococcal vaccines on these patients.

“There are currently new pneumococcal vaccines already available for adults and that are being or will be released for children, with 15 to 20 valences,” Gaschignard said. “It would be very interesting to monitor the serotypes of infections in children with sickle cell disease, a vulnerable population.”