OBJECTIVE To analyze the biological characteristics and genomic features of highly lytic bacteriopha-ges isolated from sewage in tropical hospitals and provide references for the hospital-associated infection prevention and control of multidrug-resistant Acinetobacter baumannii(MDR-Ab).METHODS With MDR-Ab as the host bacterium,bacteriophages were isolated from sewage.Transmission electron microscopy was employed to observe their morphology,and determine the optimal multiplicity of infection(MOI),one-step growth curve and environ-mental stability.Whole-genome sequencing and bioinformatics analysis were conducted to annotate functional genes and construct a phylogenetic tree.RESULTS A virulent bacteriophage,HN_Aba_01,was isolated.Elec-tron microscopy revealed that it belonged to the Myoviridae family,with a head diameter of 50 nm and a tail length of 90 nm.This bacteriophage exhibited strong lytic activity,with an optimal MOI of 0.000 000 1,a latent period of 5 minutes and a lysis yield of 15 PFU/cell.It remained stable at temperatures ranging from 4 ℃ to 60 ℃and pH values from 3 to 10.Genomic analysis identified 85 ORFs,including lyase,perforin and depolymerase genes.It shared 98.12％identity with the bacteriophage AbP2 genome(reference genome)and was classified into the Obolenskvirus genus.CONCLUSIONS The bacteriophage isolated from tropical hospital sewage,with high lyt-ic activity and good environmental adaptability,can be used for the hospital-associated infection prevention and control of MDR-Ab.

OBJECTIVE To analyze the biological characteristics and genomic features of highly lytic bacteriopha-ges isolated from sewage in tropical hospitals and provide references for the hospital-associated infection prevention and control of multidrug-resistant Acinetobacter baumannii(MDR-Ab).METHODS With MDR-Ab as the host bacterium,bacteriophages were isolated from sewage.Transmission electron microscopy was employed to observe their morphology,and determine the optimal multiplicity of infection(MOI),one-step growth curve and environ-mental stability.Whole-genome sequencing and bioinformatics analysis were conducted to annotate functional genes and construct a phylogenetic tree.RESULTS A virulent bacteriophage,HN_Aba_01,was isolated.Elec-tron microscopy revealed that it belonged to the Myoviridae family,with a head diameter of 50 nm and a tail length of 90 nm.This bacteriophage exhibited strong lytic activity,with an optimal MOI of 0.000 000 1,a latent period of 5 minutes and a lysis yield of 15 PFU/cell.It remained stable at temperatures ranging from 4 ℃ to 60 ℃and pH values from 3 to 10.Genomic analysis identified 85 ORFs,including lyase,perforin and depolymerase genes.It shared 98.12％identity with the bacteriophage AbP2 genome(reference genome)and was classified into the Obolenskvirus genus.CONCLUSIONS The bacteriophage isolated from tropical hospital sewage,with high lyt-ic activity and good environmental adaptability,can be used for the hospital-associated infection prevention and control of MDR-Ab.

Objective:To explore the association between hair trace element and all-cause death in the elderly in Hainan Province.Methods:The subjects of the study were elderly people from China Hainan Centenarian Cohort Study, a total of 163 elderly were included. The association between hair trace element level and all-cause death was analyzed by using Cox proportional risk regression model.Results:After fully adjusting the covariates, the multiple Cox proportional hazards regression analyses showed that selenium (Se), manganese (Mn), strontium (Sr) concentrations in hair were significantly associated with all-cause mortality, the hazard ratio ( HR) were 0.72 (95% CI: 0.54-0.98, P=0.035), 1.50 (95% CI: 1.07-2.11, P=0.020) and 0.54 (95% CI: 0.37-0.79, P=0.001), respectively. Subgroup and cross analysis showed that hair copper (Cu) were significant association with death in the people with anemia, the HR were 1.81 (95% CI: 1.13-2.88, P=0.013). And, hair Mn interacted with anemia, the HR was 0.46 (95% CI: 0.22-0.94, P=0.033). Conclusions:Se, Mn and Sr concentrations in hair were associated with the elevated risk for all-cause death in the elderly in Hainan. Se, Mn and Sr concentrations in hair can be used as a reference index for the prediction of the death risk of long-lived elderly in community, suggesting that the daily diet of elderly people are rich and diverse, in order to maintain normal and balanced trace element content in the body.