Molecular investigation of the transmission dynamics of brucellosis observed among children in the province of south - East Anatolia, Turkey

Abstract

Background: Brucellosis is a zoonotic disease caused by Brucella species. Although brucellosis is considered as an occupational disease in adults, recently it has become an infectious disease affecting all age groups, including children. Molecular epidemiological studies are crucial for control and treatment of disease in children. Objectives: This study aimed at identifying Brucella species, to detect antibiotic susceptibilities and define transmission dynamics between the Brucella isolates in children. Methods: A total of 77 Brucella isolates were identified by conventional and polymerase chain reaction methods. Anti - biotic susceptibilities were investigated by E - test strips. The isolates were genotyped by using multiple locus variable number tandem repeat analysis (MLVA) (MLVA - 16 Orsay), including 8 mini - satellite (panel 1) and 8 microsatellite (panel 2A and 2B) markers. Results: The mean age was 9.14±3.4 years. All patients had been consuming unpasteurized milk. All isolates were Brucella melitensis biovar 3. Only 2 isolates were resistant to ceftriaxone, while the other isolates were susceptible to other antimicrobial agents. The MLVA - 16 typing revealed 42 MLVA profiles. Eighteen profiles included 2 or more isolates, indicating a clustering rate of 66.7%. Twenty - four isolates showed a unique profile. Single locus, double locus, and 3 locus variants were detected in 32, 26, and 15 isolates, respectively. Bruce 30, Bruce 16, Bruce 9, Bruce 7, and Bruce 4 were highly discriminatory loci, respectively. All strains were defined as genotype 122, according to MLVA - 11, and genotype 43 according to MLVA - 8, and were in the Eastern Mediterranean genotype. Conclusions: High clustering rate revealed that brucellosis among the children mainly resulted from common sources. Controlling animal movements and avoiding contaminated milk products have an importance to interrupt spread of brucellosis in children.