RESULTS: We use whole-genome sequencing to examine the origin and adaptation of 524 global weedy rice samples representing all major regions of rice cultivation. Weed populations have evolved multiple times from cultivated rice, and a strikingly high proportion of contemporary Asian weed strains can be traced to a few Green Revolution cultivars that were widely grown in the late twentieth century. Latin American weedy rice stands out in having originated through extensive hybridization. Selection scans indicate that most genomic regions underlying weedy adaptations do not overlap with domestication targets of selection, suggesting that feralization occurs largely through changes at loci unrelated to domestication.
CONCLUSIONS: This is the first investigation to provide detailed genomic characterizations of weedy rice on a global scale, and the results reveal diverse genetic mechanisms underlying worldwide convergent rice feralization.
DESIGN: Prospective multicenter observational study from June 2020 to September 2022.
SETTING: Fifteen PICUs in PACCMAN.
PATIENTS: All children younger than 18 years old diagnosed with pneumonia and admitted to the PICU.
INTERVENTIONS: None.
MEASUREMENTS AND MAIN RESULTS: Clinical, microbiologic, and outcome data were recorded. The primary outcome was PICU mortality. Univariate and multivariable logistic regression was performed to investigate associations between PICU mortality and explanatory risk factors on presentation to the PICU. Among patients screened, 846 of 11,778 PICU patients (7.2%) with a median age of 1.2 years (interquartile range, 0.4-3.7 yr) had pneumonia. Respiratory syncytial virus was detected in 111 of 846 cases (13.1%). The most common bacteria were Staphylococcus species (71/846 [8.4%]) followed by Pseudomonas species (60/846 [7.1%]). Second-generation cephalosporins (322/846 [38.1%]) were the most common broad-spectrum antibiotics prescribed, followed by carbapenems (174/846 [20.6%]). Invasive mechanical ventilation and noninvasive respiratory support was provided in 438 of 846 (51.8%) and 500 of 846 (59.1%) patients, respectively. PICU mortality was 65 of 846 (7.7%). In the multivariable logistic regression model, age (adjusted odds ratio [aOR], 1.08; 95% CI, 1.00-1.16), Pediatric Index of Mortality 3 score (aOR, 1.03; 95% CI, 1.02-1.05), and drowsiness (aOR, 2.73; 95% CI, 1.24-6.00) were associated with greater odds of mortality.
CONCLUSIONS: In the PACCMAN contributing PICUs, pneumonia is a frequent cause for admission (7%) and is associated with a greater odds of mortality.