Background:Hinggan League is located in the Northeast of the Inner Mongolia Autonomous Region,the historically endemic area of animal and human brucellosis.In this study,the epidemiological characteristics of human br...Background:Hinggan League is located in the Northeast of the Inner Mongolia Autonomous Region,the historically endemic area of animal and human brucellosis.In this study,the epidemiological characteristics of human brucellosis were analyzed,and the genotypic profile and antimicrobial susceptibilities of Brucella melitensis strains isolated from humans in Hinggan League were investigated.Methods:The epidemic characteristics were described using case number,constituent ratio,and rate.The 418 human blood samples were collected and tested by bacteriology,and suspect colonies were isolated and identified by conventional biotyping assays,the VITEK 2.0 microbial identification system,and AMOS(Brucella abortus,B.melitensis,B.ovis,and B.suis)-PCR.Subsequently,all strains were genotyped using multiple-locus variable-number tandem repeat analysis(MLVA)assays,and the antimicrobial susceptibility pattern of Brucella strains against the 10 most commonly used antibiotics was determined by microdilution method.Results:A total of 22848 cases of human brucellosis were reported from 2004 to 2019,with an annual average incidence of 87.2/100000.The incidence rates in developed areas of animal husbandry(Horqin Youyi Qianqi[161.2/100000]and Horqin Youyi Zhongqi[112.1/100000])were significantly higher than those in forest areas(Arxan[19.2/100000])(χ2=32.561,P<0.001).In addition,peak morbidity occurred during May–August,accounting for 72.6%(16582/22848)of cases.The highest number of cases occurred in the 40+age group,accounting for 44.4%(10137/22484)of cases,and morbidity in males was significantly higher than that in females in all age groups(χ2=299.97,P<0.001),the most common occupation was farmers.A total of 54 B.melitensis strains were divided into 37 genotypes(GT1–37)with 80–100%genetic similarity.All 25 strains were sensitive to seven tested antibiotics,phenotypic resistance to cotrimoxazole and azithromycin was observed in 5(20%)and 25(100%)of the isolates,respectively.Conclusions:Human brucellosis exhibited a significant increasing trend and B.melitensis is the main pathogen responsible for human brucellosis in this region.Improved surveillance of infected animals(sheep)and limiting their transfer and trade are optional strategies for decreasing the incidence of this disease.展开更多
基金This study was supported by the National Key R&D Program of China(Grant No.2019YFC1200705)the China Special Grant for the Prevention and Control of Infectious Diseases(Grant Nos.2018ZX10734401 and 2018ZX10734404)the Nature Science Fund of Inner Mongolia Autonomous Region(Grant No.2018MS08004).
文摘Background:Hinggan League is located in the Northeast of the Inner Mongolia Autonomous Region,the historically endemic area of animal and human brucellosis.In this study,the epidemiological characteristics of human brucellosis were analyzed,and the genotypic profile and antimicrobial susceptibilities of Brucella melitensis strains isolated from humans in Hinggan League were investigated.Methods:The epidemic characteristics were described using case number,constituent ratio,and rate.The 418 human blood samples were collected and tested by bacteriology,and suspect colonies were isolated and identified by conventional biotyping assays,the VITEK 2.0 microbial identification system,and AMOS(Brucella abortus,B.melitensis,B.ovis,and B.suis)-PCR.Subsequently,all strains were genotyped using multiple-locus variable-number tandem repeat analysis(MLVA)assays,and the antimicrobial susceptibility pattern of Brucella strains against the 10 most commonly used antibiotics was determined by microdilution method.Results:A total of 22848 cases of human brucellosis were reported from 2004 to 2019,with an annual average incidence of 87.2/100000.The incidence rates in developed areas of animal husbandry(Horqin Youyi Qianqi[161.2/100000]and Horqin Youyi Zhongqi[112.1/100000])were significantly higher than those in forest areas(Arxan[19.2/100000])(χ2=32.561,P<0.001).In addition,peak morbidity occurred during May–August,accounting for 72.6%(16582/22848)of cases.The highest number of cases occurred in the 40+age group,accounting for 44.4%(10137/22484)of cases,and morbidity in males was significantly higher than that in females in all age groups(χ2=299.97,P<0.001),the most common occupation was farmers.A total of 54 B.melitensis strains were divided into 37 genotypes(GT1–37)with 80–100%genetic similarity.All 25 strains were sensitive to seven tested antibiotics,phenotypic resistance to cotrimoxazole and azithromycin was observed in 5(20%)and 25(100%)of the isolates,respectively.Conclusions:Human brucellosis exhibited a significant increasing trend and B.melitensis is the main pathogen responsible for human brucellosis in this region.Improved surveillance of infected animals(sheep)and limiting their transfer and trade are optional strategies for decreasing the incidence of this disease.
