Structure and Functional Properties of Bacterial Communities in Surface Sediments of the Recently Declared Nutrient-Saturated Lake Villarrica in Southern Chile.

Lake Villarrica, one of Chile's main freshwater water bodies, was recently declared a nutrient-saturated lake due to increased phosphorus (P) and nitrogen (N) levels. Although a decontamination plan based on environmental parameters is being established, it does not consider microbial parameters. Here, we conducted high-throughput DNA sequencing and quantitative polymerase chain reaction (qPCR) analyses to reveal the structure and functional properties of bacterial communities in surface sediments collected from sites with contrasting anthropogenic pressures in Lake Villarrica. Alpha diversity revealed an elevated bacterial richness and diversity in the more anthropogenized sediments. The phylum Proteobacteria, Bacteroidetes, Acidobacteria, and Actinobacteria dominated the community. The principal coordinate analysis (PCoA) and redundancy analysis (RDA) showed significant differences in bacterial communities of sampling sites. Predicted functional analysis showed that N cycling functions (e.g., nitrification and denitrification) were significant. The microbial co-occurrence networks analysis suggested Chitinophagaceae, Caldilineaceae, Planctomycetaceae, and Phycisphaerae families as keystone taxa. Bacterial functional genes related to P (phoC, phoD, and phoX) and N (nifH and nosZ) cycling were detected in all samples by qPCR. In addition, an RDA related to N and P cycling revealed that physicochemical properties and functional genes were positively correlated with several nitrite-oxidizing, ammonia-oxidizing, and N-fixing bacterial genera. Finally, denitrifying gene (nosZ) was the most significant factor influencing the topological characteristics of co-occurrence networks and bacterial interactions. Our results represent one of a few approaches to elucidate the structure and role of bacterial communities in Chilean lake sediments, which might be helpful in conservation and decontamination plans.

Evaluation of Local Pediatric Out-of-Hospital Cardiac Arrest and Emergency Services Response.

Background: Survival after pediatric out-of-hospital cardiac arrest is poor. Paramedic services provide critical interventions that impact survival outcomes. We aimed to describe local pediatric out-of-hospital cardiac arrest (POHCA) events and evaluate the impact of the paramedic service response to POHCA. Methods: The Canadian Resuscitation Outcomes Consortium and corresponding ambulance call records were used to evaluate deviations from best practice by paramedics for patients aged 1 day to <18 years who had an atraumatic out-of-hospital cardiac arrest between 2012 and 2020 in Middlesex-London County. Deviations were any departure from protocol as defined by Middlesex-London Paramedic Services. Results: Fifty-one patients were included in this study. All POHCA events had at least one deviation, with a total of 188 deviations for the study cohort. Return of spontaneous circulation (ROSC) was achieved in 35.3% of patients and 5.8% survived to hospital discharge. All survivors developed a new, severe neurological impairment. Medication deviations were most common (n = 40, 21.3%) followed by process timing (n = 38, 20.2%), vascular access (n = 27, 14.4%), and airway (n = 27, 14.4%). A delay in vascular access was the most common deviation (n = 25, 49.0%). The median (IQR) time to epinephrine administration was 8.6 (5.90-10.95) min from paramedic arrival. Cardiac arrests occurring in public settings had more deviations than private settings (p = 0.04). ROSC was higher in events with a deviation in any circulation category (p = 0.03). Conclusion: Patient and arrest characteristics were similar to other POHCA studies. This cohort exhibited high rates of ROSC and bystander cardiopulmonary resuscitation but low survival to hospital discharge. The study was underpowered for its primary outcome of survival. The total deviations scored was low relative to the total number of tasks in a resuscitation. Epinephrine was frequently administered outside of the recommended timeframe, highlighting an important quality improvement opportunity.

Validation of ICD-10 codes for the identification of paediatric out-of-hospital cardiac arrest patients.

AIM: There is a need for large-scale epidemiological studies of paediatric out-of-hospital cardiac arrest (POHCA). To enable this, we developed and validated international classification of disease (ICD-10) search algorithms for the identification of POHCA patients from health administrative data. METHODS: We validated the algorithms with a registry of POHCA (CanRoc) as the reference standard. The reference standard included all atraumatic POHCA in Middlesex-London region for January 2012-June 2020. All algorithms included 1 day to <18-year-old patients transported to emergency department (ED) by ambulance and excluded trauma. We tested three algorithms, which were applied to the National Ambulatory Care Reporting System and Discharge Abstract Database. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR) and negative likelihood ration (NLR) were calculated for each algorithm. RESULTS: During the study period, 17,688 children presented to the ED by ambulance. The reference standard included 51 POHCA patients. The algorithm using only ICD-10 code for cardiac arrest had a sensitivity of 65.5% and PPV of 90%. The algorithm with the highest sensitivity of 87.3% added sudden infant death syndrome, drowning or asphyxiation with CPR in addition to the cardiac arrest codes for inpatient and ED records. This algorithm had a specificity of 99.9%, PPV of 81.4% and NPV of âˆ¼100.0%. CONCLUSION: It is important that algorithms used for cohort identification are validated prior to use. The ICD-10 code for cardiac arrest alone misses many POHCA cases but the use of additional codes can improve the sensitivity while maintaining specificity.