Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Ail and PagC-Related Proteins in the Entomopathogenic Bacteria of Photorhabdus Genus

Among pathogenic Enterobacteriaceae, the proteins of the Ail/OmpX/PagC family form a steadily growing family of outer membrane proteins with diverse biological properties, potentially involved in virulence such as human serum resistance, adhesion and entry into eukaryotic culture cells. We studied the proteins Ail/OmpX/PagC in the bacterial Photorhabdus genus. The Photorhabdus bacteria form symbiotic complexes with nematodes of Heterorhabditis species, associations which are pathogenic to insect larvae. Our phylogenetic analysis indicated that in Photorhabdus asymbiotica and Photorhabdus luminescens only Ail and PagC proteins are encoded. The genomic analysis revealed that the Photorhabdus ail and pagC genes were present in a unique copy, except two ail paralogs from P. luminescens. These genes, referred to as ail1Pl and ail2Pl, probably resulted from a recent tandem duplication. Surprisingly, only ail1Pl expression was directly controlled by PhoPQ and low external Mg2+ conditions. In P. luminescens, the magnesium-sensing two-component regulatory system PhoPQ regulates the outer membrane barrier and is required for pathogenicity against insects. In order to characterize Ail functions in Photorhabdus, we showed that only ail2Pl and pagCPl had the ability, when expressed into Escherichia coli, to confer resistance to complement in human serum. However no effect in resistance to antimicrobial peptides was found. Thus, the role of Ail and PagC proteins in Photorhabdus life cycle is discussed

Human serum resistance of <i>Escherichia coli</i> XL1Blue strains carrying the plasmid pUC19 and its derivatives harboring <i>ail</i> or <i>pagC</i> genes.

<p>Overnight grown bacteria were tested for viability at 37°C in 50% serum (black histograms) or heat-inactivated serum (hatched histograms). The resistance was expressed as the difference in log kill between XL1-Blue harboring pUC19 incubated in 50% human serum and XL1Blue harboring the recombinant plasmid incubated either in 50% human serum or heat-inactivated serum. Means and standard errors of results from triplicate experiments are shown.</p

Only <i>ail1</i>_Pl is directly regulated by PhoP.

<p><b>A</b>. RT-qPCR: <i>ail1</i>_Pl expression is PhoP-dependent. Total RNA from <i>phoP</i> mutant or TT01 wild-type strain of <i>Photorhabdus luminescens</i> was used for RT-qPCR analysis with internal primers specific for the indicated genes. mRNA levels were normalized against those of a reference gene (<i>gyrB</i>). Data are presented as a ratio of values for <i>phoP</i> mutant and TT01 wild-type strain. A ratio of 1 indicates no difference in expression level between both strains. The bars indicate standard errors calculated using Taylor's series. Significant differences (<i>p</i>-value <0.05) are indicated by asterisks (*). The relative quantification results were obtained from three independent experiments with the REST 2009 program. <b>B</b>. Gene transcription monitored by GFP quantification: <i>ail1</i>_Pl promoter region is positively regulated by PhoP. The dynamic expression of <i>ail1</i>_Pl and <i>ail2</i>_Pl promoter in TT01 and <i>phoP</i> backgrounds was monitored over time after growth in LB medium. Each histogram represents the specific fluorescence at the peak of expression for each condition. One experiment representative of more than three independent experiments is shown. Standard deviations represent technical replicates. <b>C</b>. PhoP-His binds the promoter region of <i>ail1</i>_Pl. Electrophoretic mobility shift assay was carried out to test the binding of PhoP-His protein activated <i>in vitro</i> with ACP 10 mM (P-PhoP-His) or non activated PhoP-His (PhoP-His) on <i>ail1</i>_Pl promoter. The PhoP-His concentrations indicated are in micromolar. To ensure that the fixation is specific, we used BSA proteins and poly(dI-dC) in the binding buffer. <b>D</b>. <i>ail1</i>_Pl expression is higher at low MgSO₄ concentrations. We evaluated the impact of low and high MgSO₄ concentrations on <i>ail1</i>_Pl and <i>ail2</i>_Pl expression. Cultures diluted at 1/200 were grown in M9 minimal medium supplemented with 10 µM or 10 mM MgSO₄. Each histogram represents specific fluorescence at the peak of expression for each condition. Experiments were realized at least three times.</p

The <i>Photorhabdus</i> genus harbors <i>ail</i> and <i>pagC</i> genes.

<p>A. Evolutionary relationships of Ail, PagC and OmpX-related proteins. Stars indicate branch supports higher than 0.85 (used as significance threshold). The scale bar corresponds to the number of substitutions per amino acid residue site. B. Conserved genomic context of the <i>ail</i> (up) and <i>pagC</i> (bottom) genes in <i>Photorhabdus luminescens</i> TT01 (Pl) and <i>Photorhabdus asymbiotica</i> ATCC43949 (Pa) genomes. The boxes above and below the axis represent ORFs in the forward and reverse orientations, respectively. The names of some genes are indicated. The names of genomic islands (GI) previously described in the <i>P. luminescens</i> and <i>P. asymbiotica</i> genomes <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110060#pone.0110060-Ogier1" target="_blank">[55]</a> are given.</p

Lipo-chitooligosaccharidic Symbiotic Signals Are Recognized by LysM Receptor-Like Kinase LYR3 in the Legume <i>Medicago truncatula</i>

While chitooligosaccharides (COs) derived from fungal chitin are potent elicitors of defense reactions, structurally related signals produced by certain bacteria and fungi, called lipo-chitooligosaccharides (LCOs), play important roles in the establishment of symbioses with plants. Understanding how plants distinguish between friend and foe through the perception of these signals is a major challenge. We report the synthesis of a range of COs and LCOs, including photoactivatable probes, to characterize a membrane protein from the legume <i>Medicago truncatula.</i> By coupling photoaffinity labeling experiments with proteomics and transcriptomics, we identified the likely LCO-binding protein as LYR3, a lysin motif receptor-like kinase (LysM-RLK). LYR3, expressed heterologously, exhibits high-affinity binding to LCOs but not COs. Homology modeling, based on the <i>Arabidopsis</i> CO-binding LysM-RLK AtCERK1, suggests that LYR3 could accommodate the LCO in a conserved binding site. The identification of LYR3 opens up ways for the molecular characterization of LCO/CO discrimination