Introduction: The emergence of extended-spectrum β-lactamases (ESBLs)-producing Escherichia coli clones are a public health concern worldwide. Scarce information does exist about the spread of ESBLs-producing E. coli in pediatric patients from developing countries. Methodology: E. coli strains were analyzed by multilocus-sequence-typing, pulsed-field-gel-electrophoresis and phylogenetic group. The antimicrobial-resistance genes were detected by PCR, and plasmid content by the PCR-based replicon-typing. Horizontal transfer was tested by conjugation and the location of the blaCTX-M-15 gene by Southern blot hybridization. Results: Thirty-two cefotaxime-resistant E. coli were recovered. Eleven of them were ESBL-producing isolates, which were well characterized and ascribed to seven sequence types and five phylogroups. The ESBL CTX-M-15 was the most prevalent enzyme (9 of 11). Plasmids of variable sizes (40-220 kb) were visualized, and the incompatibility (Inc) group FIB plasmid-replicon was detected in the ESBL strains and transferred by conjugation in 45.45% of them. Plasmid-borne toxin-antitoxin systems were the most frequently detected systems, strongly associated to IncF plasmids. The CTX-M-15-encoding gene was located on IncFIB plasmids. Conclusions: Even though a small number of ESBL-producing strains was recovered, we evidenced that IncFIB plasmids carry the blaCTX-M-15 gene, highlighting the role of IncF-type plasmids in facilitating the spread and maintenance of ESBL-encoding genes, which further favors the rapid increase of the antimicrobial resistance dissemination in disease-causing E. coli strains in pediatric patients.

La tuberculosis en el niño representa de 5 a 30% de los casos. La tuberculosis meníngea representa la forma más grave de tuberculosis en el paciente pediátrico por su alta mortalidad y secuelas neurológicas. Objetivo: Conocer la epidemiología clínica y la evolución de la tuberculosis meníngea para facilitar el diagnóstico y tratamiento en pediatría. Material y métodos: Realizamos una revisión retrospectiva de 13 años de expedientes clínicos electrónicos de 15 niños con tuberculosis meníngea, ingresados en el Hospital para el Niño Poblano. El diagnóstico se fundamentó principalmente en cuadro clínico, citoquímico de líquido cefalorraquídeo y tomografía axial computarizada de cráneo. Se analizaron las variables: edad, sexo, signos, síntomas, patología previa, métodos diagnósticos y mortalidad. Resultados: Un total de ABSTRACT Introduction: Tuberculosis in children represents 5 to 30% of cases. Meningeal tuberculosis represents a serious form of tuberculosis in pediatric patients due to its high mortality and neurological sequelae. Objective: Know epidemiology, clinical signs and evolution of meningeal tuberculosis to facilitate diagnosis and treatment in pediatric patients. Material and methods: We conducted a retrospective review of electronic clinical records of 15 children with meningeal tuberculosis, admitted to Hospital del Niño Poblano in 13.5 years. The diagnosis was based mainly on clinical symptoms, cerebrospinal fluid analysis and computed tomography of the skull. The variables were analyzed: age, sex, signs, symptoms, previous pathology, diagnostic methods and mortality. Results: Total of 12 patients. Average age 9.5 years, 41.5% older than