Molecular characterization of Brucella species from Zimbabwe.

Brucella abortus and B. melitensis have been reported in several studies in animals in Zimbabwe but the extent of the disease remains poorly known. Thus, characterizing the circulating strains is a critical first step in understanding brucellosis in the country. In this study we used an array of molecular assays including AMOS-PCR, Bruce-ladder, multiple locus variable number tandem repeats analysis (MLVA) and single nucleotide polymorphisms from whole genome sequencing (WGS-SNP) to characterize Brucella isolates to the species, biovar, and individual strain level. Sixteen Brucella strains isolated in Zimbabwe at the Central Veterinary laboratory from various hosts were characterized using all or some of these assays. The strains were identified as B. ovis, B. abortus, B. canis and B. suis, with B. canis being the first report of this species in Zimbabwe. Zimbabwean strains identified as B. suis and B. abortus were further characterized with whole genome sequencing and were closely related to reference strains 1330 and 86/8/59, respectively. We demonstrate the range of different tests that can be performed from simple assays that can be run in laboratories lacking sophisticated instrumentation to whole genome analyses that currently require substantial expertise and infrastructure often not available in the developing world. Author summary Brucellosis is endemic in Zimbabwe. This article describes the use of various assays such as AMOS, Bruce-ladder, MLVA, and whole genome sequencing to characterize Brucella species isolated from different animals in Zimbabwe. Choice of which assays to use in the laboratory is generally done considering reproducibility, robustness, expertise and affordability in a given setting. As evidenced in this study, most laboratories in Africa lack resources especially finances, equipments and expertise to perform necessary tests for diagnosis and identification of specific pathogens. The study shows that the differentiation of species can be correctly concluded from the analysis with AMOS, Bruce-ladder and MLVA16 assays. Furthermore, MLVA16 can be used as an epidemiological tool and traceback of outbreaks. These PCR assays can therefore add to the control and eradication of brucellosis, since the Brucella species (B. ovis, B. abortus, B. suis and B. canis) existing in Zimbabwe could be identified and characterized.