First isolation, identification and genetic characterization of Brucella abortus biovar 3 from dairy cattle in Bangladesh.

Md Sadequl Islam,Md Ariful Islam,Giuliano Garofolo,Lorena Sacchini,Mst Minara Khatun,Amanda C Dainty,Sukumar Saha

doi:10.1002/vms3.193

Abstract

BackgroundBrucellosis is a zoonotic disease caused by bacteria Brucella spp. belonging to the genus Brucella. It is endemic in domesticated animals in Bangladesh. Isolation, identification and genetic characterization of Brucella spp. in dairy cattle are essential to undertake appropriate control and preventive measures. The study was conducted to isolate and characterize the Brucella spp. circulating in dairy cattle.MethodsUterine discharge (n = 45), milk (n = 115), vaginal swab (n = 71), placenta (n = 7) and aborted fetus (n = 2) were collected. Brucella selective agar plates were inoculated with samples and incubated at 37 ◦C for 14 days under 5% CO2 for isolation of Brucella spp. Brucella suspected colonies were recovered from samples were confirmed by genus and species specific PCR assays. Genetic characterization was performed by Multi Locus Variable number tandem‐repeat Analysis‐16 (MLVA‐16).ResultsThe isolates of Brucella recovered from samples were confirmed as B. abortus by AMOS‐ERY PCR assay. The classical biotyping method confirmed all 10 B. abortus isolates belonged to the biovar 3. The MLVA‐16 assay indicated all B. abortus isolates identical and the same genotype 40, based on panel 1 MLVA‐8.ConclusionDendrogram analysis revealed all B. abortus isolates of the study were identical to three isolates from Brazil, one isolate of France and closely related to Chinese isolates. This is the first report of isolation and genetic characterization of B. abortus from the dairy cattle in Bangladesh.

Highlights

Brucellosis is a worldwide zoonotic infection of economic and public health importance caused by bacteria from genus Brucella (Mathew et al, 2015)
A total of 240 samples consisted of uterine discharges (n = 45), milk (n = 115), vaginal swabs (n = 71), placenta (n = 7) and aborted fetuses (n = 2) were collected from dairy cattle with the clinical sign
The Brucella are known to be shed in the aborted materials of cattle such as: uterine discharge, vaginal swab, placenta and fetus

Summary

| INTRODUCTION

Brucellosis has been reported in humans and animals in Bangladesh (Islam, Khatun, Werre, Sriranganathan, & Boyle, 2013; Rahman et al, 2012). Isolation of Brucella at the genus level has been reported in milk sample of cattle (Islam et al, 2018). Brucella genus‐specific DNA has been identified in the sera of humans by real time PCR assay (Rahman et al, 2012). Identifi‐ cation of Brucella at species level and its biovar typing and genetic characterization of circulating Brucella spp. has not been reported in Bangladesh. The objectives of the present research work are: i) isolation of Brucella spp. from dairy cattle experiencing abortion, ii) identification of Brucella at species and biovar levels and iii) genetic characterization of circulating Brucella spp. by MLVA‐16 assay

| MATERIALS AND METHODS

| DISCUSSION

Findings

ETHICAL STATEMENT