Fronts divide diazotroph communities in the Southern Indian Ocean

International audienceDinitrogen (N2) fixation represents a key source of reactive nitrogen in marine ecosystems. While the process has been rather well-explored in low latitudes of the Atlantic and Pacific Oceans, other higher latitude regions and particularly the Indian Ocean have been chronically overlooked. Here, we characterize N2 fixation and diazotroph community composition across nutrient and trace metals gradients spanning the multifrontal system separating the oligotrophic waters of the Indian Ocean subtropical gyre from the high nutrient low chlorophyll waters of the Southern Ocean. We found a sharp contrasting distribution of diazotroph groups across the frontal system. Notably, cyanobacterial diazotrophs dominated north of fronts, driving high N2 fixation rates (up to 13.96 nmol N l−1 d−1) with notable peaks near the South African coast. South of the fronts non-cyanobacterial diazotrophs prevailed without significant N2 fixation activity being detected. Our results provide new crucial insights into high latitude diazotrophy in the Indian Ocean, which should contribute to improved climate model parameterization and enhanced constraints on global net primary productivity projections. © The Author(s) 2024

Fronts divide diazotroph communities in the Southern Indian Ocean

Dinitrogen (N-2) fixation represents a key source of reactive nitrogen in marine ecosystems. While the process has been rather well-explored in low latitudes of the Atlantic and Pacific Oceans, other higher latitude regions and particularly the Indian Ocean have been chronically overlooked. Here, we characterize N-2 fixation and diazotroph community composition across nutrient and trace metals gradients spanning the multifrontal system separating the oligotrophic waters of the Indian Ocean subtropical gyre from the high nutrient low chlorophyll waters of the Southern Ocean. We found a sharp contrasting distribution of diazotroph groups across the frontal system. Notably, cyanobacterial diazotrophs dominated north of fronts, driving high N-2 fixation rates (up to 13.96 nmol N l(-1) d(-1)) with notable peaks near the South African coast. South of the fronts non-cyanobacterial diazotrophs prevailed without significant N-2 fixation activity being detected. Our results provide new crucial insights into high latitude diazotrophy in the Indian Ocean, which should contribute to improved climate model parameterization and enhanced constraints on global net primary productivity projections.131,0694,2Q1Q2SCIE11,

Fronts divide diazotroph communities in the Southern Indian Ocean

International audienceDinitrogen (N2) fixation represents a key source of reactive nitrogen in marine ecosystems. While the process has been rather well-explored in low latitudes of the Atlantic and Pacific Oceans, other higher latitude regions and particularly the Indian Ocean have been chronically overlooked. Here, we characterize N2 fixation and diazotroph community composition across nutrient and trace metals gradients spanning the multifrontal system separating the oligotrophic waters of the Indian Ocean subtropical gyre from the high nutrient low chlorophyll waters of the Southern Ocean. We found a sharp contrasting distribution of diazotroph groups across the frontal system. Notably, cyanobacterial diazotrophs dominated north of fronts, driving high N2 fixation rates (up to 13.96 nmol N l−1 d−1) with notable peaks near the South African coast. South of the fronts non-cyanobacterial diazotrophs prevailed without significant N2 fixation activity being detected. Our results provide new crucial insights into high latitude diazotrophy in the Indian Ocean, which should contribute to improved climate model parameterization and enhanced constraints on global net primary productivity projections. © The Author(s) 2024

Comparison of surgical management and outcomes of acute right colic and sigmoid diverticulitis: a French national retrospective cohort study

International audienceBackground: Acute right colic diverticulitis (ARD) is less frequent in Western countries than acute sigmoid diverticulitis (ASD). We aimed to compare the management of ARD and ASD operated on in emergency.Methods: All consecutive patients who had emergency surgery for ASD and ARD (2010-2021) were included in a retrospective, multicenter, cohort study. Patients were identified from databases in French centers that were members of the French Surgical Association. Emergency surgery was performed during the same hospitalization for peritonitis or after failure of conservative treatment. Early and late postoperative outcomes were studied.Results: A total of 2297 patients were included with 2256 (98.2%) ASD and 41 (1.8%) ARD patients. Baseline characteristics were similar. Overall, patients were rated Hinchey 3-4 (63.9%, n = 1468, p = 0.287). ARD was more often treated with resection and anastomosis, protected or not (53.7%, n = 22), whereas ASD was mainly treated with resection and terminal ostomy (62.5% (n = 1409), p < 0.001). Median operative time was shorter for ARD (120 vs 146 min, p = 0.04). The group of ARD patients showed a higher prevalence of Clavien III/IV complications compared to the group of ASD patients, although no statistically significant difference was observed (41.5%, n = 17 vs. 27.6%, n = 620, p = 0.054). However 90-day mortality only happened in ASD patients (9.8%, n = 223 vs 0, p = 0.03). ARD patients had more diverticulitis recurrence (46.3%, n = 19 vs 13.4%, n = 303, p < 0.001). Multivariate analysis identified female sex as a protective factor for recurrence [odds ratio (OR) 0.55, p < 0.001] and ARD as a risk factor (OR 8.85, p < 0.001).Conclusion: Operated on in emergency, ARDs have more resection anastomosis, with a similar rate of complications, less mortality, and more recurrence of diverticulitis than ASD

Risk factors for emergency surgery for diverticulitis: A retrospective multicentric French study at 41 hospitals

International audienceBackgroundThe observed increase in the incidence of complicated diverticulitis may lead to the performance of more emergency surgeries. This study aimed to assess the rate and risk factors of emergency surgery for sigmoid diverticulitis.MethodThe primary outcomes were the rate of emergency surgery for sigmoid diverticulitis and its associated risk factors. The urgent or elective nature of the surgical intervention was provided by the surgeon and in accordance with the indication for surgical treatment. A mixed logistic regression with a random intercept after multiple imputations by the chained equation was performed to consider the influence of missing data on the results.ResultsBetween 2010 and 2021, 6,867 patients underwent surgery for sigmoid diverticulitis in the participating centers, of which one-third (n = 2317) were emergency cases. In multivariate regression analysis with multiple imputation by chained equation, increasing age, body mass index &lt;18.5 kg/m2, neurologic and pulmonary comorbidities, use of anticoagulant drugs, immunocompromised status, and first attack of sigmoid diverticulitis were independent risk factors for emergency surgery. The likelihood of emergency surgery was significantly more frequent after national guidelines, which were implemented in 2017, only in patients with a history of sigmoid diverticulitis attacks.ConclusionThe present study highlights a high rate (33%) of emergency surgery for sigmoid diverticulitis in France, which was significantly associated with patient features and the first attack of diverticulitis

Impact of the first wave of COVID-19 epidemy on the surgical management of sigmoid diverticular disease in France: National French retrospective study

International audienceObjective: To analyze the surgical management of sigmoid diverticular disease (SDD) before, during, and after the first containment rules (CR) for the first wave of COVID-19.Methods: From the French Surgical Association multicenter series, this study included all patients operated on between January 2018 and September 2021. Three groups were compared: A (before CR period: 01/01/18-03/16/20), B (CR period: 03/17/20-05/03/20), and C (post CR period: 05/04/20-09/30/21).Results: A total of 1965 patients (A n = 1517, B n = 52, C n = 396) were included. The A group had significantly more previous SDD compared to the two other groups (p = 0.007), especially complicated (p = 0.0004). The rate of peritonitis was significantly higher in the B (46.1%) and C (38.4%) groups compared to the A group (31.7%) (p = 0.034 and p = 0.014). As regards surgical treatment, Hartmann's procedure was more often performed in the B group (44.2%, vs A 25.5% and C 26.8%, p = 0.01). Mortality at 90 days was significantly higher in the B group (9.6%, vs A 4% and C 6.3%, p = 0.034). This difference was also significant between the A and B groups (p = 0.048), as well as between the A and C groups (p = 0.05). There was no significant difference between the three groups in terms of postoperative morbidity.Conclusion: This study shows that the management of SDD was impacted by COVID-19 at CR, but also after and until September 2021, both on the initial clinical presentation and on postoperative mortality

EPIdemiology of Surgery-Associated Acute Kidney Injury (EPIS-AKI): study protocol for a multicentre, observational trial

Introduction More than 300 million surgical procedures are performed each year. Acute kidney injury (AKI) is a common complication after major surgery and is associated with adverse short-term and long-term outcomes. However, there is a large variation in the incidence of reported AKI rates. The establishment of an accurate epidemiology of surgery-associated AKI is important for healthcare policy, quality initiatives, clinical trials, as well as for improving guidelines. The objective of the Epidemiology of Surgery-associated Acute Kidney Injury (EPIS-AKI) trial is to prospectively evaluate the epidemiology of AKI after major surgery using the latest Kidney Disease: Improving Global Outcomes (KDIGO) consensus definition of AKI.Methods and analysis EPIS-AKI is an international prospective, observational, multicentre cohort study including 10 000 patients undergoing major surgery who are subsequently admitted to the ICU or a similar high dependency unit. The primary endpoint is the incidence of AKI within 72 hours after surgery according to the KDIGO criteria. Secondary endpoints include use of renal replacement therapy (RRT), mortality during ICU and hospital stay, length of ICU and hospital stay and major adverse kidney events (combined endpoint consisting of persistent renal dysfunction, RRT and mortality) at day 90. Further, we will evaluate preoperative and intraoperative risk factors affecting the incidence of postoperative AKI. In an add-on analysis, we will assess urinary biomarkers for early detection of AKI.Ethics and dissemination EPIS-AKI has been approved by the leading Ethics Committee of the Medical Council North Rhine-Westphalia, of the Westphalian Wilhelms-University Münster and the corresponding Ethics Committee at each participating site. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and used to design further AKI-related trials.Trial registration number NCT04165369