Imported human brucellosis in Belgium: Bio and molecular typing of bacterial isolates, 1996-2015

Abstract

ObjectivesThe aim of this study was to characterize by classical biotyping and Multi-Locus variable number tandem repeats (VNTR) Analysis (MLVA) all Brucella spp. derived from human cases in Belgium from 1996 to 2015. Final goals were to determine the species and biovar, to trace-back on genetic grounds the origin of each strain when patient history and risk factors were missing, and to survey for particular trends at the national level.MethodsA total of 37 Brucella strains, isolated from 37 patients in Belgium, were analyzed by both classical biotyping and MLVA, and the genetic patterns compared to those of human strains isolated worldwide.ResultsClassical biotyping revealed that isolates were mainly Brucella melitensis. Most of them belonged to biovar 3, the most abundant biovar in the Mediterranean region. MLVA confirmed that Brucella melitensis is too diverse in VNTRs to be able to make clusters associated to each biovar, but it allowed retrieving precious epidemiological information. The analysis highlighted the imported nature of the strains from all over the world with a dominant part from the Mediterranean countries. Findings of the MLVA11 testing were in line with the travel history of patients coming from Italy, Turkey, Lebanon and Peru. The analysis was particularly useful because it suggested the geographical origin of the infection for 12/16 patients for whom no case history was available.ConclusionClassical biotyping and MLVA analysis are not exclusive but remain complementary tools for Brucella melitensis strain surveillance. MLVA11 is sufficient for Brucella-free countries such as Belgium to trace the geographical origin of infection, but complete MLVA16 is needed to search for links with endemic areas.

Prevalence and risk factors of brucellosis among veterinary health care professionals

“…Several reports have indicated prevalence of brucellosis ranging from 2.26 to 34% in veterinarians and para-veterinarians from high milk producing states in northern, western and southern regions of India [27][28][29]. Worldwide, reported incidence of human brucellosis varies widely, from <0.01 to >200 per 100,000 population in endemic disease areas [2]. Human brucellosis has been extensively reported among pyrexia of unknown origin (PUO) cases, veterinarians, animal handlers and slaughterhouse workers in India [17,[30][31][32].…”

“…More than 60% of emerging human pathogens are zoonotic [1] and brucellosis is the most widespread zoonosis in the world caused by bacteria belonging to genus Brucella [2][3][4][5]. Among the recognized 12 Brucella species, Brucella melitensis, Brucella suis and Brucella abortus are the major human pathogens resulting in considerable disability and morbidity [6,7].…”

“…India is recognized as geographical hotspot for brucellosis [2] and increased prevalence of brucellosis in livestock has been reported in recent years [5]. In India, brucellosis in livestock is responsible for a median loss of US $3.4 billion per year [14].…”

An Overview of Brucellosis in Cattle and Humans, and its Serological and Molecular Diagnosis in Control Strategies

“…Brucella abortus and B. suis infection is widespread throughout Central America [ 38 ]. In Europe, human brucellosis is thought to be associated with travellers and immigrants from the Middle East or the private import of dairy products from endemic areas [ 37 , 39 , 40 , 41 ].…”

Shedding of Brucella melitensis happens through milk macrophages in the murine model of infection

“…In the second group, the unmodified B. melitensis 16 M reference strain (16 M) was used. In the third group, the field strain B. melitensis L311/15 (FS) isolated from a Turkish patient in Belgium was used 37 . Bacteria were grown in biosafety level 3 laboratory facilities overnight in 2YT media (Luria-Bertani broth with double quantity of yeast extract) shaking at 37 °C, and were washed twice in PBS (3,500 rpm, 10 min) before inoculating the mice.…”