Extensively Drug-Resistant(XDR)Salmonella Typhi Outbreak by Waterborne Infection——Beijing Municipality,China,January-February 2022

Summary What is already known about this topic?Typhoid fever remains a major public health problem in developing countries.Waterborne typhoid fever affects an estimated 27 million people worldwide each year.Decades of indiscriminate antibiotic usage has driven the emergence and spread of multidrug-resistant(MDR)and even extensively drug-resistant(XDR)Salmonella Typhi(S.Typhi)strains.

Cyanobacteria-based self-oxygenated photodynamic therapy for anaerobic infection treatment and tissue repair

Photodynamic therapy(PDT)is an important technique to deal with drug-resistant bacterial infections in the post-antibiotic era.However,the hypoxic environment in intractable infections such as refractory keratitis and periodontitis,makes PDT more difficult.In this work,spontaneous oxygen-producing cyanobacteria were used as the carrier of photosensitizer(Ce6),and ultrasmall Cu_(5.4)O nanoparticles(Cu_(5.4)O USNPs)with catalase activity for infection and inflammation elimination and rapid tissue repair(CeCycn-Cu_(5.4)O).The loading of Ce6 and Cu_(5.4)O USNPs onto cyanobacteria surface were confirmed by transmission electron microscopy,nano particle size analyzer,scanning electron microscopy.In vitro sterilization and biofilm removal experiments demonstrated that the restriction of hypoxic environment to PDT was significantly alleviated due to the oxygen production of cyanobacteria.Under laser irradiation,the close transfer of energy photons to oxygen produced by cyanobacteria reduced more than 90% of Ce6 dosages(660 nm,200 mW/cm^(2),2 min).It is worth mentioning that both rapid sterilization through PDT and long-term oxidized free radicals elimination were achieved by adjusting the ratio of Ce6 and Cu_(5.4)O USNPs.Both periodontitis and refractory keratitis animal models proved the excellent self-oxygenation enhanced antibacterial property and promotion of tissue repair.

High-power continuous-wave optical waveguiding in a silica micro/nanofibre

As miniature fibre-optic platforms,micro/nanofibres(MNFs)taper-drawn from silica fibres have been widely studied for applications from optical sensing,nonlinear optics to optomechanics and atom optics.While continuous-wave(CW)optical waveguiding is frequently adopted,so far almost all MNFs are operated in low-power region(e.g.,<0.1 W).Here,we demonstrate high-power low-loss CW optical waveguiding in MNFs around 1550-nm wavelength.We show that a pristine MNF,even with a diameter down to 410 nm,can waveguide an optical power higher than 10 W,which is about 30 times higher than demonstrated previously.Also,we predict an optical damage threshold of 70 W.In highpower CW waveguiding MNFs,we demonstrate high-speed optomechanical driving of microparticles in air,and second harmonic generation efficiency higher than those pumped by short pulses.Our results may pave a way towards high-power MNF optics,for both scientific research and technological applications.

Acute salinity and temperature challenges during early development of zebrafish:Differential gene expression of PTHs,PTHrPs and their receptors

Parathyroid hormone(pth),parathyroid hormone-related peptide(pthrp)and their receptors are involved in the regulation of calcium homeostasis in all vertebrates.To further understand the role of these genes in teleosts during development,we investigated the expression pattern of pth1,pth2,pthrp1,pthrp2,and their receptors pth1r,pth2r,pth3r,and their response to acute salinity and temperature challenge during early development of zebrafish,Danio rerio.The results revealed that pth1,pth2,pthrp1,pthrp2,pth1r,pth2r,pth3r were differentially expressed during early development,and pth1,pthrp1,pth1r,pth2r mRNA were detected from 0 hpf.pth2 and pth3r mRNA were detected after fertilization.Exposure of zebrafish embryos and larvae to acute osmotic(30)stress for 15 min failed to modify the expression levels of pthrp2 mRNA from levels in control fish.However,salinity challenge significantly(P<0.01)modified pth1,pth2,pth3r at 3 dpf,pthrp1(P<0.01)and pth1r(P<0.05)were both significantly modified at 5 dpf,and pth2r was significantly(P<0.01)modified at 4 dpf and 5 dpf.Exposure of embryos and larvae to a cold(18℃)stress generally up-regulated mRNA levels of pth1,pth2,pthrp1,pthrp2 and pth3r from 2 dpf to 5 dpf,while a hot(38℃)stress generally down-regulated mRNA levels of these genes.After acute temperature challenge,expression levels of pth receptors were greatly influenced except pth2r.The results indicate that the contribution of pth1,pth2,pthrp1,pthrp2,pth1r,pth2r and pth3r genes to the stress response in zebrafish may be stressor-specific during early development.Overall,the results from this study provide a basis for further research into the developmental and stressor-specific role of pth1,pth2,pthrp1,pthrp2,pth1r,pth2r and pth3r in zebrafish.