Epidemiological, Clinical and Molecular Characterization of Human Brucellosis in Bosnia and Herzegovina – An Ongoing Brucellosis Outbreak

Abstract

Objective. The aim of this study was to evaluate an ongoing outbreak of brucellosis in southern region of Bosnia and Herzegovina (BIH) on the epidemiological, clinical and molecular level.

Patients and methods. This study included 19 patients affected by brucellosis between 2015 and 2017, in Trebiševo (BIH). Out of 19 patients, 16 were admitted to and treated at the Department of Infectious diseases of the University Clinical Hospital Mostar, while three patients were treated in ambulatory care setting. Epidemiological, clinical and microbiological parameters were investigated. The Rose Bengal test (RBT) positive sera were serologically confirmed by complement fixation test (CFT). We also analyzed blood cultures, and isolates were additionally serotyped. Molecular analyses were performed with Bruce-ladder multiplex polymerase chain reaction (PCR) and multiple locus variable number of tandem repeat analysis of 16 loci (MLVA-16) assay.

Results. Fifteen out of 19 patients had been professionally exposed to the bacterium, while four patients acquired brucellosis without prior contact with infected animals. In seven out of eight (87.5%) patients with localized form of brucellosis, we detected significantly higher values of C-reactive protein (CRP) or erythrocyte sedimentation rate (P<0.001). B. melitensis was isolated from 13/16 (81.3%) blood culture samples, and additionally serotyped as biovar 3. Using MLVA-16 assay, 11 isolates were genotyped. We observed complete genotype matches among 8/11 B. melitensis isolates, while 3/11 isolates differed in Bruce04 locus.

Conclusion. Overall, our study confirms the usefulness of MLVA-16 method in the epidemiological and molecular research of brucellosis during epidemic that, most likely, originated from the same source.