The poor prognosis of infections associated with multidrug-resistant Pseudomonas aeruginosa can be attributed to several conditions of the patient and virulence factors of the pathogen, such as the type III secretion system (T3SS), which presents the ability to inject four effectors into the host cell: ExoS, ExoT, ExoU and ExoY. The aim of this study was to analyze the distribution of exo genes through multiplex polymerase chain reaction in P. aeruginosa strains isolated from patients at a third-level pediatric hospital and their relationships with clinical variables, e.g., the origin of the sample, susceptibility profile and outcome, through a multinomial logistic regression model. A total of 336 bacterial strains were obtained from cystic fibrosis (CF; n = 55) and bloodstream infection (BSI; n = 281) samples, and eleven presence (+)/absence (−) exo virulotype patterns were identified. The virulotype V3 (exoU−/exoS+/exoT+/exoY+) was observed in 64.28%, followed by V1 (exoU+/exoS−/exoT+/exoY+) with 11.60%. Additionally, V2 (exoU+/exoS−/exoT+/exoY−) was present in 11.60%, and V7 (exoU−/exoS+/exoT+/exoY−) was present in 4.17%. The remaining virulotypes (8.33%) identified were clustered in the other virulotype (OV) group (V4, V5, V6, V8, V9, V10 and V11). The clinical records of 100 patients and their outcomes were reviewed. Fifteen patients died (CF = 4; BSI = 11). V2 and V1 were the virulotypes most related to pandrug resistance (PDR), whereas the V1 relative risk of death was determined to be almost four-fold greater than that of V3, followed by V2 and OV. In summary, the virulotypes V1, V2 and CF are related to death. This study highlights the association of T3SS virulotypes with the susceptibility profile, clinical origin and their potential for predicting a poor prognosis.

Alagille syndrome (ALGS) is a multisystem disorder characterized by a paucity of intrahepatic bile ducts and cholestasis, often requiring liver transplantation before adulthood. Due to the lack of genotype–phenotype correlation, case series are essential to understand disease presentation and prognosis. Data on Mexican ALGS patients are limited. Therefore, we aimed to characterize a large series of Mexican patients by consolidating cases from major institutions and independent geneticists, with the goal of generating one of the most comprehensive cohorts in Latin America. We retrospectively analyzed clinical records of pediatric ALGS patients, focusing on demographics, clinical features, laboratory and imaging results, biopsy findings, and transplant status. Genetic testing was performed for all cases without prior molecular confirmation. We identified 52 ALGS cases over 13 years; 22 had available clinical records. Of these, only 6 had molecular confirmation at study onset, prompting genetic testing in the remaining 16. We identified six novel JAG1 variants and several previously unreported phenotypic features. A liver transplantation rate of 13% was observed in the cohort. This study represents the largest molecularly confirmed ALGS cohort in Mexico to date. Novel genetic and clinical findings expand the known spectrum of ALGS and emphasize the need for improved therapies, such as IBAT inhibitors, which may alleviate symptoms and reduce the need for transplantation.

Atypical bacterial pathogens present the ability to induce pulmonary damage. At present, there are no available phenotypic diagnosis tests that achieve up to 100% reliability. Therefore, clinicians must utilise molecular techniques for the detection and identification of these pathogens. The main objective of this research was to evaluate the prevalence of atypical bacteria in paediatric patients from different age groups. A total of 609 clinical samples were collected from paediatric patients who presented with an adverse respiratory condition during the period from March 2021 to February 2024. DNA was extracted from the samples, and end-point PCR was performed to detect atypical bacteria. Statistical analyses were performed to evaluate the bacterial prevalence and assess clinical data from newborns and mothers that could be related to RDS. A total of 139 patients exhibited at least one atypical organism (22.82%). Ureaplasma parvum was more prevalent in neonates, while M. pneumoniae and C. pneumoniae were more prevalent in older infants. Atypical bacteria can be present in all seasons of the year, but their prevalence increases during hot weather. Mixed infections due to atypical bacteria may occur. The risk factors related to the development of RDS are prematurity, low weight, and orotracheal intubation.

Background/Objectives: Cystic fibrosis (CF) is a multisystem disease caused by CFTR gene variants, with a high prevalence of vitamin D (VitD) deficiency despite the supplementation and schedules specifically developed for this population. Lower VitD levels have been associated with an increased risk of respiratory infections and pulmonary exacerbations in CF, with some pilot studies indicating the potential benefits of supplementation during acute episodes. This study aimed to describe the occurrence of VitD deficiency according to the supplemented dose in pediatric patients with CF. Methods: A cross-sectional analytical study was conducted to assess serum VitD levels in a pediatric population with cystic fibrosis. Clinical and biochemical data were collected, along with information on VitD intake and pancreatic enzyme dosage at the time of evaluation. Results: A total of 48 patients were included in the study. Normal VitD levels were observed in 41.7% of the patients, insufficiency in 31.3%, and deficiency in 27%. The median VitD intake was 2050 IU. A statistically significant difference was observed in patients with a daily intake exceeding 2000 IU. Only 10% of patients achieved levels above 30 ng/mL with a lower dose. No statistically significant association was identified between the pancreatic enzyme dosage and vitamin D levels. Conclusions: Vitamin D deficiency/insufficiency is a persistent problem in the pediatric CF population; the interventions targeting factors associated with this condition are required to refine supplementation schedules. These findings underscore the need for personalized strategies to optimize vitamin D status in PwCF. Ideally, these strategies should consider all associated factors, including genetic variants; however, with limited resources, our results suggest that a daily dose of 2000 IU of vitamin D may represent a reasonable and effective starting point for supplementation.

Survival in cystic fibrosis (CF) has improved markedly in high-income countries over recent decades; however, important disparities persist across regions. Long-term data describing survival patterns and their determinants in middle-income settings remain limited. The aim of this study was to estimate survival in Mexican patients with CF over three decades and to explore the clinical and health-system factors associated with mortality. we conducted a retrospective longitudinal cohort study including patients with a confirmed diagnosis of CF followed at a national tertiary referral center in Mexico between 1990 and 2020. Survival was estimated using the Kaplan-Meier method. Potential predictors of mortality were evaluated through univariate analyses and multivariable Cox proportional hazards regression. Temporal changes in demographic, clinical, nutritional, microbiological, and treatment-related characteristics were also examined. a total of 341 patients were included. Median estimated survival was 20 years (95% CI 17.3-23.0) and appeared to improve over time. In multivariable analyses, early detection of P. aeruginosa ≤7 years, malnutrition, and reduced pulmonary function were associated with increased mortality, whereas access to complete standard CF treatment was associated with lower mortality. survival among Mexican patients with CF has improved over the past three decades but continues to lag that reported in high-income countries. The findings suggest that long-term outcomes are strongly influenced by modifiable clinical factors and access to comprehensive care. Strengthening multidisciplinary management, ensuring equitable treatment availability, and developing national CF registries may be essential steps toward reducing avoidable mortality and narrowing global survival disparities.

Introducción. La fibrosis quística es una patología que requiere diagnóstico precoz, seguimiento multidisciplinario y acceso a terapias especializadas. La diversidad de los sistemas de salud en América Latina podría impactar en la calidad de la atención. Objetivo. El objetivo fue describir las prácticas clínicas, los recursos diagnósticos y el acceso terapéutico en los centros que atienden fibrosis quística en la región. Métodos. Estudio transversal descriptivo realizado mediante una encuesta en línea aplicada en 2024 a 101 profesionales de la salud de América Latina. Se estudiaron las características institucionales, carga asistencial, disponibilidad de cribado neonatal, organización multidisciplinaria, métodos diagnósticos y acceso a moduladores del regulador de la conductancia transmembrana de la fibrosis quística (CFTR). Resultados. Se analizaron 101 respuestas de profesionales; 52 encuestados (51,5%) trabajaban en centros especializados en fibrosis quística y 49 (48,5%) en centros no especializados, distribución que corresponde al 100% de la muestra. Los encuestados que trabajaban en centros especializados reportaron una mayor carga de pacientes y equipos multidisciplinarios más completos. El cribado neonatal y la prueba de sudor fueron reportados como disponibles por 58 (57,4%) y 50 (49,5%) de los encuestados, respectivamente. Las pruebas genéticas y los moduladores del regulador de la conductancia transmembrana de la fibrosis quística (CFTR) mostraron una disponibilidad limitada y variable entre países. Conclusiones. La atención de la fibrosis quística en América Latina es heterogénea. Estandarizar protocolos, fortalecer los centros especializados y mejorar el acceso al diagnóstico molecular y las terapias avanzadas son prioridades regionales que mejorarían el diagnóstico y tratamiento oportuno, así como la sobrevida de los pacientes.