Predictive accuracy of Sepsis-3 definitions for mortality among adult critically ill patients with suspected infection

Background: Sepsis-3 definitions have been published recently;however, their diagnostic value remains controversial. This study was to assess the accuracy of Sepsis-3 definitions compared to Sepsis-1 definitions by stratifying mortality among adult critically ill patients with suspected infection. Methods: A multicenter, prospective cohort study was conducted from November 10, 2017 to October 10, 2018, in five Intensive Care Units (ICUs) at four teaching hospitals. Thirty-day mortality was compared across categories for both Sepsis-3 definitions and Sepsis-1 definitions, which were evaluated by logistic regression analysis followed by measurement of the area under the receiver operating characteristic curve (AUROC) for predicting 30-day mortality rates. Results: Of the 749 enrolled patients, 644 (85.9%) were diagnosed with sepsis according to the Sepsis-1 definitions. Among those patients, 362 were diagnosed with septic shock (362/749, 48.3%). However, according to the Sepsis-3 definitions, there were 483 patients with a diagnosis of sepsis (483/749, 64.5%), among whom 299 patients were diagnosed with septic shock (299/749, 39.9%). According to the Sepsis-3 definitions, sepsis (sepsis and septic shock) patients had higher 30-day mortality (41.8%) than sepsis patients according to the Sepsis-1 definitions (31.8%,χ^2 = 5.552, P = 0.020). The AUROC of systemic inflammatory response syndrome (SIRS) and quick sequential organ failure assessment (qSOFA) scores with regard to 30-day mortality rates were 0.609 (0.566-0.652) and 0.694 (0.654-0.733), respectively. However, the AUROC of SOFA scores (0.828 [0.795-0.862]) were significantly higher than that of SIRS or qSOFA scores (P < 0.001). Conclusion: In adult critically ill patients with suspected infection, the Sepsis-3 definitions were relatively accurate in stratifying mortality and were superior to the Sepsis-1 definitions.

Impact of a novel Rickettsia symbiont on the life history and virus transmission capacity of its host whitefly(Bemisia tabaci)

Rickettsia consists of some of the most prevalent symbionts of insects and often plays a significant role in the biology of its hosts.Recently,a maternally inherited Torix group Rickettsia,provisionally named as RiTBt,was recorded in a species of notorious pest whitefly,tentatively named as Asia II 1,from the Bemisia tabaci complex.The role of this Rickettsia in the biology of its host is unknown.Here we investigated the impact of RiTBt on the performance and virus transmission capacity of Asia II 1.RiTBt did not significantly affect the life history parameters of the whitefly when the host insect was reared on tobacco,tomato,and cotton,three host plants with relatively low,medium and high suitability to the whitefly.Intriguingly,RiTBt slightly enhanced whitefly transmission of cotton leaf curl Multan virus(CLCuMuV),a virus that is transmitted by the whitefly in the field and has caused extensive damage to cotton production.Specifically,compared with whiteflies without RiTBt,following a 48 h virus acquisition whiteflies with RiTBt had higher titer of virus and showed higher efficiency of virus transmission.A rickettsial secretory protein BtR242 was identified as a putative virus-binding protein,and was observed to interact with the coat protein of CLCuMuV in vitro.Viral infection of the whitefly downregulated gene transcript levels of the BtR242 gene.These observations indicate that RiTBt has limited impact on the biology of the Asia II 1 whitefly,and whether this symbiont has functions in the biology of other host whiteflies warrants future investigation.

Whole-genome single nucleotide polymorphism and mating compatibility studies reveal the presence of distinct species in sub-Saharan Africa Bemisia tabaci whiteflies

In sub-Saharan Africa cassava growing areas,two members of the Bemisia tabaci species complex termed sub-Saharan Africa 1(SSA1)and SSA2 have been reported as the prevalent whiteflies associated with the spread of viruses that cause cassava mosaic disease(CMD)and cassava brown streak disease(CBSD)pandemics.At the peak of CMD pandemic in the late 1990s,SSA2 was the prevalent whitefly,although its numbers have diminished over the last two decades with the resurgence of SSA1 whiteflies.Three SSA1 subgroups(SGI to SG3)are the predominant whiteflies in East Africa and vary in distribution and biological properties.Mating compatibility between SSA1 subgroups and SSA2 whiteflies was reported as the possible driver for the resurgence of SSA 1 whiteflies.In this study,a combination of both phylogenomic methods and reciprocal crossing experiments were applied to determine species status of SSA1 subgroups and SSA2 white-fly populations.Phylogenomic analyses conducted with 26548205 bp whole genome single nucleotide polymorphisms(SNPs)and the full mitogenomes clustered SSA1 subgroups together and separate from SSA2 species.Mating incompatibility between SSA1 subgroups and SSA2 further demonstrated their distinctiveness from each other.Phylogenomic analyses conducted with SNPs and mitogenomes also revealed different genetic relationships among SSA1 subgroups.The former clustered SSA 1-SGI and SSA1-SG2 to-gether but separate from SSA1-SG3,while the latter clustered SSA1-SG2 and SSA1-SG3 together but separate from SSA 1-SG1.Mating compatibility was observed between SSA 1-SGI and SSA1-SG2,while incompatibility occurred between SSA 1-SGI and SSA1-SG3,and SSA 1-SG2 and SSA 1-SG3.Mating results among SSA 1 subgroups were coherent with phylogenomics results based on SNPs but not the full mitogenomes.Furthermore,this study revealed that the secondary endosymbiont--did not mediate reproductive success in the crossing assays carried out.Overall,using genome wide SNPs together with reciprocal crossings assays,this study established accurate genetic relationships among cassava-colonizing populations,illustrating that SSA1 and SSA2 are distinct species while at least two species occur within SSA1 species.