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Objective:To analyze the mutation characteristics of rpoB gene in rifampicin-resistant Brucella strains. Methods:DNA of 4 rifampicin-resistant Brucella strains (JSY-26, G-9, WSY-13 and AW-3) isolated from Xinjiang Uygur Autonomous Region was selected, rifampicin rpoB gene was amplified by PCR and its nucleotide sequence was sequenced. The rpoB gene sequences of rifampicin-resistant Brucella standard strain (RB51) and sensitive strain (ALT-8) were used as reference, the mutation sites and types of the rpoB gene inside and outside the rifampicin resistance determination region (RRDR) of the 4 rifampicin-resistant Brucella strains were analyzed by Mega 7.0 software. Results:Through sequence alignment, both JSY-26 and WSY-13 strains underwent a single base point mutation at the RRDR 1 576 bp of the rpoB gene, with the base changing from guanine (G) to adenine (A). The G-9 strain underwent a single base point mutation at the RRDR 1 606 bp of the rpoB gene, with the base changing from cytosine (C) to A. The AW-3 strain showed 5 mutations of 3 types outside rpoB gene RRDR at 2 536, 2 537, 2 626, 2 636 and 2 654 bp, namely 3 insertion mutations [thymine (T) insertion once and C insertion twice], 1 deletion mutation (C deletion), and 1 single base point mutation (from G to C mutation).Conclusion:The RRDR mutations in the rpoB gene of the rifampicin-resistant Brucella strains are mainly characterized by single base point mutations, while multiple insertion and deletion mutations occur outside the RRDR.
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Objective:To investigate the epidemic status and molecular characteristics of Borrelia burgdorferi in ticks in Xinjiang Uygur Autonomous Region (referred to as Xinjiang). Methods:From April to June 2020, 312 samples of Ixodes were collected in 6 areas of Yili, Alashankou, Hutubi, Qinghe, Fuhai and Wujiaqu, Xinjiang. Nested PCR and fluorescence quantitative PCR were used to detect Borrelia burgdorferi in ticks. The positive samples by both methods were genotyped and identified by nested PCR products. Results:The positive rates of nested PCR and fluorescence quantitative PCR were 8.97% (28/312) and 11.86% (37/312), respectively. Among them, the fluorescence quantitative PCR positive rate of Qinghe was the highest of 35.29% (12/34), and the positive rate of Fuhai was the lowest of 2.00% (1/50). The positive samples by both methods was 26. Genotyping results showed that 12 samples were highly homologous to Borrelia garinii, 10 copies to Borrelia burgdorferi sensu stricto, and 4 copies to Borrelia afzelii. Conclusions:The positive rate of Borrelia burgdorferi in ticks in Xinjiang is higher, which has confirmed that there are 3 pathogenic Borrelia burgdorferi genotypes in Xinjiang. The dominant genotype is Borrelia garinii, followed by Borrelia burgdorgferi sensu stricto genotype and Borrelia afzelii genotype.
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Objective To identify molecular typing of Brucella abortus isolates in Xinjiang,and determine the identification ability of multiple locus variable-number tandem repeat analysis (MLVA).Methods The optimized Brucella AMOS-PCR was used for identification of Brucella (n =7) genus and species in Xinjiang from 2010-2015,and MLVA-16 was used to further identify the isolates.Results were compared with the data of the Brucella standard strain provided by the http://mlva.u-psud.fr database.Cluster analysis was carried out with Bionumerics 6.6.Results The results of AMOS-PCR and MLVA-16 were identical,all were Brucella abortus.Further classification results of the MLVA-16 showed that the strain in Xinjiang was type 3 of Brucella abortus,which was basically the same as that of the domestic Brucella.Conclusions The molecular typing of isolates separated in Xinjiang is type 3 of Brucella abortus.MLVA can identify Brucella at the level of species,and highly sensitive to Brucella biotype and isolates differences,which provides a basis for the traceability and evolution of brucellosis epidemic strains.
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Objective To explore the drug sensibility of Brucella from bovine and sheep in Xinjiang.Methods Using paper diffusion method,19 drugs of 8 kinds of antibiotics including aminoglycosides,macrolides,sulfonamides,tetracyclines,β-lactams,fluoroquinolones,chloramphenicols and rifamycins,were tested.Drug sensitivity test was conducted on 57 Brucella strains isolated from bovine and sheep in Xinjiang from 2010 to 2016.Results The 57 Brucella strains were highly sensitive to doxycycline,tetracycline,streptomycin,tobramycin,gentamicin,amikacin,amoxicillin,ofloxacin,fleroxacin,ciprofloxacin and chloramphenicol,with the sensitivity rates were all higher than 90％;and they were highly resistance to azithromycin,clarithromycin and bactrim,with the drug resistance rates were all higher than 80％.Conclusion Brucella from bovine and sheep in Xinjiang is sensitive to tetracyclines,aminoglycosides,β-1actams,fluoroquinolones and chloramphenicols.