Analysis of the Brucella melitensis epidemic in Xinjiang: Genotyping, polymorphism, antibiotic resistance and tracing

Abstract

Brucella spp. are facultative intracellular pathogens that cause the zoonosis- brucellosis worldwide. There has been a trend of the re-emergence of brucellosis worldwide in recent years. Xinjiang is located in northwestern China and in the hinterland of the Eurasian continent. The epidemic situation of brucellosis is serious in Xinjiang. To analyze the epidemic situation of Brucella spp. in Xinjiang among humans and animals, this study used 16S rRNA amplification to identify 144 isolates of Brucella and their biovars. MLVA, drug resistance testing, and wgSNP detection were also performed. At the same time, analysis based on the published data of Brucella isolates worldwide was conducted. The results showed that the dominant species was B. melitensis biovar 3 and the correlation among isolates was high, whether in humans or animals. Since 2010, the polymorphism of isolates in Xinjiang has been increasing each year. No reported amikacin/kanamycin-resistant strains were found, but 6 rifampicin-intermediate isolates were found without rpoB gene variation. The NJ tree of the wgSNP results indicated that there were three main complexes of the B. melitensis epidemic in Xinjiang. In conclusion, the dominant Brucella species has greatest genetic variation in Xinjiang than other location in China, and the rifampicin-resistant trend has been existed in Xinjiang. This study analyzes the prevalence, genotyping, diversity, drug resistance, and tracing of B. melitensis in Xinjiang. The results provide basic data for the prevention and control of brucellosis in Xinjiang and China.