Human gut microbiota composition associated with international travels.

OBJECTIVE: The objective of this study was to evaluate whether long stays in non-European countries influence the composition, diversity, and dynamics of gut microbiota, considering the potential impact of travelling, close contact with new people, and consumption of water and food. METHODS: Two prospective cohorts were analyzed: (i) A longitudinal cohort comprising long-term travellers who provided fecal samples before and after their travels. (ii) A cohort consisting of long-term travellers and recently arrived migrants from non-European countries, which was compared with non-traveller controls. Each participant self-collected fecal samples and provided demographic and epidemiological data. Microbiota was characterized through 16 S rRNA gene sequencing. RESULTS: The longitudinal cohort comprised 17 subjects. A trend toward higher bacterial diversity was observed after travelling (Shannon index 3.12vs3.26). When comparing 84 travellers/migrants with 97 non-travellers, a confirmed association of higher diversity levels with travelling was observed (Phylogenetic diversity: 22.1vs20.9). Specific genera enriched in travellers' gut microbiota were identified, including Escherichia/Shigella, Bacteroides, and Parabacteroides. The analysis revealed three major clusters with profound differences in their bacterial composition, which exhibited differential distribution between travellers and non-travellers (Adonis P < 0.001; R2 = 30.6 %). Two clusters were more frequently observed in travellers: The first cluster, characterized by dominance of Escherichia/Shigella, exhibited the lowest levels of richness and diversity. The second cluster, dominated by Faecalibacterium and Bacteroides, displayed the highest richness and diversity patterns. CONCLUSION: These findings highlight the diverse impact of international travel on gut microbiota composition and underscore the importance of considering microbiota resilience and diversity in understanding the health implications.

Non-Pharmacological Interventions During SARS-CoV-2 Pandemic: Effects on Pediatric Viral Respiratory Infections.

INTRODUCTION: Viral lower respiratory tract infections frequently cause morbidity and mortality in children. The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic led to isolation and hygiene measures, resulting in decreased respiratory virus transmission and pediatric admissions. This study aimed to assess the impact of these measures and their uplifting on respiratory virus circulation in children before and during the SARS-CoV-2 pandemic (January 2017-December 2022). METHODS: We conducted a weekly time series analysis of multiple virus molecular assays in children. This included those admitted to a university reference hospital's Pediatric Intensive Care Unit (PICU) and those with risk pathologies exhibiting fever and/or respiratory symptoms. We included patients aged 0-18 years residing in Catalonia and adjusted the positive results to account for diagnostic effort. RESULTS: We performed a total of 2991 respiratory virus tests during the period. Confinement significantly decreased the detection of all viruses, especially Rhinovirus (RV). After the deconfinement of children, the viral detection trend remained stable for all viruses, with no short-term impact on virus transmission. The mandatory implementation of facemasks in those aged ≥6 years led to decreased viral circulation, but we observed an influenza virus rebound after facemask removal. At that time, we also noticed an interrupted drop in the detection rates of RV and respiratory syncytial virus (RSV). The reopening of schools led to a progressive increase in viral detections, especially of Rhinovirus. CONCLUSION: Non-pharmacological interventions significantly impact the circulation of respiratory viruses among children. We observed these effects even when some measures did not specifically target preschool-aged children.

Nirsevimab immunization's real-world effectiveness in preventing severe bronchiolitis: A test-negative case-control study.

BACKGROUND: Several clinical trials have shown that nirsevimab, an antibody targeting the respiratory syncytial virus (RSV), reduces RSV bronchiolitis requiring admission. In 2023-2024, Catalonia and Andorra adopted immunization strategies for children <6 months and those born during the epidemic season. This study evaluates the effectiveness of nirsevimab in preventing hospitalizations from RSV bronchiolitis. METHODS: In the epidemic season of 2023-2024, a test-negative case-control study was conducted in three hospitals from Catalonia and Andorra. Patients <12 months old admitted with bronchiolitis and tested for RSV using molecular microbiology tests were included. The effectiveness in preventing RSV bronchiolitis hospitalization and severe disease was estimated using multivariate models. Comparisons between immunized, non-immunized, and non-eligible patients were made in prospectively collected epidemiological, clinical, and microbiological variables. RESULTS: Two hundred thirty-four patients were included. RSV was detected in 141/234 (60.2%), being less common in the immunized group (37% vs 75%, p < .001). The rate of immunized patients among those eligible was 59.7%. The estimated effectiveness for RSV-associated lower respiratory tract infection was 81.0% (95% confidence interval: 60.9-90.7), and for preventing severe disease (the need for NIV/CMV), 85.6% (41.7-96.4%). No significant differences by immunization status were observed in patients with RSV concerning viral coinfections, the need for NIV/CMV or length of hospital stay. CONCLUSIONS: This study provides real-world evidence of the effectiveness of nirsevimab in preventing RSV-lower respiratory tract infection hospitalization and severe disease in infants during their first RSV season following a systematic immunization program. Immunized patients did not exhibit a higher rate of viral coinfections nor differences in clinical severity once admitted.

Impact of universal immunization program with monoclonal antibody nirsevimab on reducing the burden of serious bronchiolitis that need pediatric intensive care.

RSV bronchiolitis remains the leading cause of hospitalization in children under 1 year of age. It is estimated that 2-6% of cases will be hospitalized on pediatric intensive care units (PICUs). In October 2023, a universal immunization program with the monoclonal antibody nirsevimab was implemented in Catalonia. The aim of the study was to analyze the impact of the nirsevimab immunization on the burden of bronchiolitis admitted to a PICU and resulting changes in epidemiological, clinical, and microbiological characteristics comparing the pre-nirsevimab (pre-N) with the post-nirsevimab (post-N) period. This was a prospective, descriptive, and observational study. Patients with severe bronchiolitis admitted to reference children's hospital PICU, between September 2010 and February 2024 were included. Demographic and clinical data were collected and viral laboratory etiological diagnosis was carried out. 1531 patients were recruited, 1458 in the pre-N seasons and 73 after its introduction (58% males, median age 52 days), of which 67% were immunized with nirsevimab. The total number of PICU bronchiolitis admissions, the ratio, and the RSV etiology were significantly lower in the post-N period (p = 0.03, p < 0.001, and p = 0.039, respectively). Significant higher age at admission (p < 0.001) and lower hospital length of stay (p < 0.001) was observed comparing pre-N vs. post-N period. CONCLUSION: Nirsevimab appears to have an important impact on reducing the number and length of stay of PICU admissions due to RSV bronchiolitis. WHAT IS KNOWN: • Bronchiolitis is the most common viral infection of the lower respiratory tract in infants. • It represents 13% of the total pediatric intensive care admissions, typically during winter. This is one of the causes that produces a collapse in the health care systems all around the world. WHAT IS NEW: • In October 2023, universal immunization with monoclonal antibody nirsevimab of all children under 6 months of age was started in the majority of autonomous communities in Spain. • Recent publications from the nirsevimab clinical trials have evidenced a high RSV protective effect, but data on its effect on real life patients who require pediatric intensive care unit admission are missing.

Lung ultrasound and procalcitonin, improving antibiotic management and avoiding radiation exposure in pediatric critical patients with bacterial pneumonia: a randomized clinical trial.

BACKGROUND: Pneumonia is a major public health problem with an impact on morbidity and mortality. Its management still represents a challenge. The aim was to determine whether a new diagnostic algorithm combining lung ultrasound (LUS) and procalcitonin (PCT) improved pneumonia management regarding antibiotic use, radiation exposure, and associated costs, in critically ill pediatric patients with suspected bacterial pneumonia (BP). METHODS: Randomized, blinded, comparative effectiveness clinical trial. Children < 18y with suspected BP admitted to the PICU from September 2017 to December 2019, were included. PCT was determined at admission. Patients were randomized into the experimental group (EG) and control group (CG) if LUS or chest X-ray (CXR) were done as the first image test, respectively. Patients were classified: 1.LUS/CXR not suggestive of BP and PCT < 1 ng/mL, no antibiotics were recommended; 2.LUS/CXR suggestive of BP, regardless of the PCT value, antibiotics were recommended; 3.LUS/CXR not suggestive of BP and PCT > 1 ng/mL, antibiotics were recommended. RESULTS: 194 children were enrolled, 113 (58.2%) females, median age of 134 (IQR 39-554) days. 96 randomized into EG and 98 into CG. 1. In 75/194 patients the image test was not suggestive of BP with PCT < 1 ng/ml; 29/52 in the EG and 11/23 in the CG did not receive antibiotics. 2. In 101 patients, the image was suggestive of BP; 34/34 in the EG and 57/67 in the CG received antibiotics. Statistically significant differences between groups were observed when PCT resulted < 1 ng/ml (p = 0.01). 3. In 18 patients the image test was not suggestive of BP but PCT resulted > 1 ng/ml, all of them received antibiotics. A total of 0.035 mSv radiation/patient was eluded. A reduction of 77% CXR/patient was observed. LUS did not significantly increase costs. CONCLUSIONS: Combination of LUS and PCT showed no risk of mistreating BP, avoided radiation and did not increase costs. The algorithm could be a reliable tool for improving pneumonia management. CLINICAL TRIAL REGISTRATION: NCT04217980.

¿Aprender Medicina a distancia?: percepción de estudiantes confinados por la pandemia COVID-19

Background: The suspension of face-to-face teaching activity due to the COVID-19 pandemic forced an abrupt transition to distance learning in Spanish universities. Aim: To know how medical students value distance learning in the context of COVID-19 pandemic. Material and Methods: Undergraduate medical students from first to fifth year in Barcelona (Spain) were invited to answer an anonymous online survey about their perceptions and level of satisfaction with virtual learning. Results: Of 483 students invited to the survey, 244 (50.5%) answered it. Respondents from the first and second year rated distance learning as acceptable (mean 3.1) on a Likert scale from 1 to 5. Those from third to fifth years rated distance learning as unsatisfactory (mean 2.7). The best evaluated aspects were synchronous lectures (3.9) and lectures based on cases (3.4). The worst evaluated issues were motivation (2.3), interaction with faculty (2.1), and additional workload (0.7). Conclusions: The perceptions expressed by these students reinforce the importance of facilitating communication, motivation and participation of students in distance learning in Medicine.