Objective To investigate the molecular typing,virulence,and drug resistance features of bacterial strains in a simultane-ous outbreak of paratyphoid fever A and B,and then provide evidence for the prevention and treatment of the simultaneous transmission of different types of paratyphoid fever.Methods The clinical data of 31 patients confirmed as paratyphoid fever in the Hospital of Xin-jiang Production and Construction Corps from September 2018 to November 2018 were retrospectively analyzed.The isolated strains were performed serotyping and drug sensitivity tests.The molecular typing and the detection of virulence and drug resistance genes were carried out by multiplex PCR,pulsed-field gel electrophoresis(PFGE),and multilocus sequence typing(MLST).Results A total of 32 strains of Salmonella paratyphi were isolated from 31 patients,with 19 strains classified as type A and 13 as type B.The intermedi-ate rates of all strains against ciprofloxacin were 100%.The molecular typing and serotyping results of 11 representative strains were consistent.The PFGE fingerprints of Salmonella paratyphi A and B were also consistent.The MLST of Salmonella paratyphi A was ST85,and that of Salmonella paratyphi B was ST86.All strains carried virulence island SPI1-SPI5 representative genes such as invA,sitC,sseL,sifA,mgtC,siiE,and sopB,and regulatory gene phoP.Salmonella paratyphi A also carried cytolethal distending toxin(CDT)genes with trimeric structure such as cdtB,pltA,and pltB.The virulence plasmid genes such as pefA,prot6E,and spvB were all negative.Conclusion The simultaneous transmission of Salmonella paratyphi A and B has the characteristics of high pathogenicity and poor sensitivity to ciprofloxacin,which should be highly concerned by clinical and laboratory personnel.

Objective To analyze the clinical characteristics and pathogen infection of severe patients with COVID-19 retrospectively.Methods The clinical data and laboratory test results of 85 severe COVID-19 patients combined with pathogenic bacterial infection ad-mitted to the Hospital of Xinjiang Production and Construction Corps from December 1,2022 to February 20,2023 were collected.The patients were divided into the cure group and death group based on the outcome.Meanwhile,the distribution and drug resistance of the infected pathogens were analyzed.Results The median age and length of hospitalization of 85 patients with severe COVID-19 were 82(75,84)years old and 14(9,23)days,respectively.Their most common underlying diseases were hypertension,heart disease,and diabetes.There were 63 patients in the cure group and 22 in the death group,with a mortality rate as high as 25.9%.The levels of white blood cell count,neutrophil to lymphocyte ratio,and C-reactive protein in the patients of the death group were significanly higher than those in the cure group(P<0.05).However,the percentage of lymphocytes was the opposite(P<0.05).A total of 128 strains of pathogenic bacteria were isolated from 85 patients.Among them,21 strains(16.4%)were Gram-positive bacteria,predominantly Staphylococcus aureus.66 strains(51.6%)were Gram-negative bacteria,mainly Klebsiella pneumoniae,Acinetobacter baumannii,and Pseudomonas aeruginosa.41 strains(32.0%)were fungi,primarily Candida albicans.The proportion of methicillin-resistant Staphylo-coccus aureus(MRSA)was as high as 56%,while those of carbapenem-resistant Klebsiella pneumoniae,Acinetobacter baumannii,and Pseudomonas aeruginosa were 14%,50%,and 18%,respectively.Conclusion The severe COVID-19 patients who are elderly or have underlying diseases may be infected with carbapenem-resistant Klebsiella pneumoniae,Acinetobacter baumannii,Pseudomonas aeruginosa,and MRSA.In clinical practice,rational selection of antibiotics should be made and effective measures should be taken to prevent the spread of multidrug-resistant bacteria and reduce the risk of mortality.