Pneumonia was the most common and serious clinical illness in children in Spain at the end of 2022 and beginning of 2023.

CYBER | Wednesday, April 24, 2024

In late 2022 and early 2023, Europe, including Spain, faced a significant outbreak of severe and invasive infections caused by Streptococcus pyogenes, a common bacterial pathogen in the pediatric population, accompanied by an increase in cases of mild infections such as pharyngotonsillitis and scarlet fever. Several teams from CIBER, from the areas of infectious diseases (CIBERINFEC) and respiratory diseases (CIBERES), coordinated by the pediatric services of the University Hospitals of La Paz and Gregorio Marañon, and the National Center for Microbiology (CNM) of Carlos Health. Institute III (ISCIII) studied invasive infections caused by S. pyogenes among the pediatric population throughout the country to determine whether the outbreak is due to the circulation of new, more virulent strains, decreased immunity following the pandemic, or genetic predisposition of individuals. The results of the work were published in mSphere.

“A prospective collection of strains causing severe infections in children showed that pneumonia was the most common and severe clinical condition (44.1%), followed by soft tissue abscesses (24.7%) and osteoarticular infections (11.8%). %). Almost half of the affected children required hospitalization in intensive care units (PICU),” explains Cristina Calvo, CIBERINFEC team leader, specialist in the Pediatrics and Infectious Diseases Service of La Paz Hospital in Madrid and one of the coordinators of the study.

Although more research will be needed to pinpoint the reasons for the rise in infections, the CIBER teams suggest that the rise in invasive infections due to S. pyogenes This may largely be due to the immune debt situation of patients, especially after the pandemic.

“The increase in infections may be due to a combination of factors, which may include changes in the epidemiology of the disease, such as the evolution of bacterial strains and their resistance to antimicrobial treatment, as well as environmental and behavioral factors that may contribute to the spread of infections. transmission of bacteria,” explains Eva Ramirez de Arellano, CIBERINFEC researcher at National Center for Microbiology belonging Carlos III Health Institute.

The study showed that, despite the predominant presence of strains of the emm1 and emm12 types, an important geographical dispersion of the hypervirulent strain M1UK, previously described in the UK, was found among the emm1 strains in Spain. However, this was not associated with greater severity. In addition, population differences were observed between mild and invasive strains, highlighting the presence of the emm89 type among mild cases.

“Our results suggest an overall increase in this pathogen, highlighting the need for surveillance,” he says. Jesús Oteo, scientific director of CIBERINFEC and researcher at CNM-ISCIII. “However, additional studies on the immune response to shed more light on this question are being carried out in collaboration with the CIBERINFEC group led by Rafael Cantona from the Ramón y Cajal University Hospital,” adds the director.

The project also collaborates with the pediatric network PedGas Net, coordinated by Cristina Calvo and Jesús Saavedra, CIBERINFEC – Gregorio Marañon University Hospital, and involving 51 hospitals throughout the country; as well as the Invasive Infection Surveillance Program, S. pyogenes CNM, whose head is Pilar Villalón.

Link:

Ramirez de Arellano E, Saavedra-Lozano J, Villalon P, Jove-Blanco A, Grandioso D, Sotelo J, Gamell A, Gonzalez-Lopez JJ, Cervantes E, Gonzalez MJ, Rello-Saltor V, Esteva C, Sanz-Santaeufemia F, Yague G, Manzanares A, Brañas P, Ruiz de Gopegui E, Carrasco-Colom J, Garcia F, Cersenado E, Mellado I, Del Castillo E, Perez-Vazquez M, Oteo-Iglesias H, Calvo S; Spanish Gas Research Group PedGAS-Net/CIBERINFEC. Clinical, microbiological and molecular characteristics of childhood invasive infections. Streptococcus pyogenes in Spain in the context of a global outbreak. mSphere. March 26, 2024; 9(3): e0072923. doi: 10.1128/msphere.00729-23. Epub Mar 5, 2024 PMID: 38440985.