P070
An extended genomic analysis reveals unexpected transmissions involving the pediatric population in Madrid with tuberculosis
M López-Llaría(1) G Bernal(1) S M Saleeb(1,2) M Guida(3,4) A López Suárez(3,4) C Rodríguez-Grande(1) S Buenestado Serrano(1) M J Ruiz Serrano(1) P Muñoz(1,2,5) B Santiago(3,4) L Pérez Lago(1) D García de Viedma(1,2)
1:Servicio de Microbiología clínica y Enfermedades Infecciosas, Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, 28009, España; 2:CIBER Enfermedades Respiratorias (CIBERES), Madrid, 28029, España; 3:Sección de Enfermedades Infecciosas Pediátricas, Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, 28009, España; 4:CIBER Enfermedades Infecciosas (CIBERINFEC), Madrid, 28029, España; 5:Departamento de Medicina, Universidad Complutense, Madrid, 28040, España
From an epidemiological perspective, tuberculosis (TB) in the pediatric population is of particular relevance, as children are considered sentinels of TB transmission. Genomic epidemiology enables us to characterize with the highest precision the transmission patterns involving children. Nevertheless, there is a tendency to restrict these analyses to the closest socio-epidemiological circles, involving the children with TB and their index/contact cases. In this study we followed a genomic epidemiology analysis in three sequential layers: i) focusing exclusively on children in Madrid (75 cases) and their suspected index cases (11 cases) years 2018-2025, ii) extending the analysis to compare with other unrelated adult TB cases previously sequenced from Madrid (238 cases, 2018-2025) and iii) from an unrelated population, Almería, located far from Madrid (938 cases, 2003-2025). Isolates were sequenced in the Illumina NextSeq platform with clusters being designated based on the threshold of 12 SNPs. 35% (20/57) of the children in Madrid were included in 14 clusters involving 39 cases. Eleven clusters had <5 SNPs between cases. Only two clusters corresponded to cases with previously suspected epidemiological links. Among the remaining clusters, seven of them involved children with other unrelated adults from Madrid and three included cases from Almería. In summary, most of the clusters involving children with TB in Madrid were linked with cases outside the suspected epidemiological links, which otherwise could have been overlooked. Exhaustive epidemiological interviews must be coupled to genomic analysis to understand the complexity of the transmission involving children.
Acknowledgements: COST Action AdvanceTB (CA21164), GEMIMAD study group.