RESUMO
Population genomics analysis holds great potential for informing conservation of endangered populations. We focused on a controversial case of European whitefish (Coregonus spp.) populations. The endangered North Sea houting is the only coregonid fish that tolerates oceanic salinities and was previously considered a species (C. oxyrhinchus) distinct from European lake whitefish (C. lavaretus). However, no firm evidence for genetic-based salinity adaptation has been available. Also, studies based on microsatellite and mitogenome data suggested surprisingly recent divergence (c. 2500 years bp) between houting and lake whitefish. These data types furthermore have provided no evidence for possible inbreeding. Finally, a controversial taxonomic revision recently classified all whitefish in the region as C. maraena, calling conservation priorities of houting into question. We used whole-genome and ddRAD sequencing to analyse six lake whitefish populations and the only extant indigenous houting population. Demographic inference indicated post-glacial expansion and divergence between lake whitefish and houting occurring not long after the Last Glaciation, implying deeper population histories than previous analyses. Runs of homozygosity analysis suggested not only high inbreeding (FROH up to 30.6%) in some freshwater populations but also FROH up to 10.6% in the houting prompting conservation concerns. Finally, outlier scans provided evidence for adaptation to high salinities in the houting. Applying a framework for defining conservation units based on current and historical reproductive isolation and adaptive divergence led us to recommend that the houting be treated as a separate conservation unit regardless of species status. In total, the results underscore the potential of genomics to inform conservation practices, in this case clarifying conservation units and highlighting populations of concern.
RESUMO
BACKGROUND: Patients with severe coronavirus disease 2019 (COVID) pneumonia and acute respiratory distress syndrome (C-ARDS) on invasive mechanical ventilation (IMV) have been found to be prone to having other microbial findings than severe acute respiratory syndrome coronavirus 2 (SARS-2)-CoV-19 in the bronchoalveolar lavage (BAL) fluid at intubation causing a superinfection. These BAL results could guide empirical antibiotic treatment in complex clinical situations. However, there are limited data on the relationship between microbial findings in the initial BAL at intubation and later ventilator-associated pneumonia (VAP) diagnoses. OBJECTIVE: To analyse the incidence of, and microorganisms responsible for, superinfections in C-ARDS patients at the time of first intubation through microbial findings in BAL fluid. To correlate these findings to markers of inflammation in plasma and later VAP development. DESIGN: Retrospective single-centre study. SETTING: One COVID-19 intensive care unit (ICU) at a County Hospital in Sweden during the first year of the pandemic. PATIENTS: All patients with C-ARDS who were intubated in the ICU. RESULTS: We analysed BAL fluid specimens from 112 patients at intubation, of whom 31 (28%) had superinfections. Blood levels of the C-reactive protein, procalcitonin, neutrophil granulocytes, and lymphocytes were indistinguishable between patients with and without a pulmonary superinfection. Ninety-eight (88%) of the patients were treated with IMV for more than 48 h and of these patients, 37% were diagnosed with VAP. The microorganisms identified in BAL at the time of intubation are normally found at the oral, pharyngeal, and airway sites. Only one patient had an indistinguishable bacterial strain responsible for both superinfection at intubation and in VAP. CONCLUSIONS: One fourth of the patients with C-ARDS had a pulmonary superinfection in the lungs that was caused by another microorganism identified at intubation. Routine serum inflammatory markers could not be used to identify this complication. Microorganisms located in BAL at intubation were rarely associated with later VAP development.