Evaluation of the genetic profiles of Brucella with different biotypes using MLVA and MLST techniques

Abstract

Brucella, the causative agent of brucellosis, is a globally significant zoonotic pathogen with serious public health implications. Understanding the molecular and genetic characteristics of Brucella species is crucial for the precise prevention, control, and epidemiological traceback investigation of brucellosis. In this study, 82 Brucella strains were genotyped via multiple-locus variable-number tandem-repeat analysis (MLVA-11) and multilocus sequence typing (MLST-21). Among these strains, four species and 14 biotypes were identified. MLVA-11 analysis revealed that 82 strains of bacteria contained 25 MLVA-11 genotypes, with genotype 72 (N = 10) and genotype 116 (N = 10) being the dominant genotypes. Hunter & Gaston diversity index (HGDI) analysis was conducted on the repeat results of 11 VNTR loci across all strains. These 11 VNTR loci exhibited varying degrees of polymorphism, with four loci demonstrating high levels of polymorphism. Notably, the 18 loci presented the highest degree of polymorphism, with a polymorphism index reaching 0.712. MLST-21 analysis revealed that 82 strains of Brucella contained 16 genotypes, with ST-8 (N = 33) being the dominant genotype. This study elucidates the phylogenetic relationships among diverse Brucella species. A comparison of the clustering results for 82 Brucella strains obtained via the two methods revealed that the MLVA-11 typing results more reliably encompassed the typing information provided by MLST-21. These findings provide novel insights into the molecular epidemiology of Brucella, which may facilitate the development of more effective strategies for brucellosis prevention and control.