Investigation of cross-transmission dynamics of brucellosis observed in children in the province of Diyarbakir and phylogenetic tree of the brucella isolates

Brucellosis is an infection disease caused by brucella species and is transmitted by direct contact with infected animals, consumption of fresh milk and dairy products, inhalation of bacteria of infected droplets. It causes difficulties and recurrences especially in the treatment of child patients. This study was aimed to identify the brucella species, to determine their antibiotic susceptibilities and to perform molecular epidemiological analyzes of the isolates by multilocus variable number tandem repeat analysis (MLVA) method. A total of 77 brucella strains isolated from children with brucella infection in Diyarbakır Children's Diseases Hospital between 2000 and 2013 were included in the study. Genotying of the strains were done by MLVAOrsay 16 method. Of the 77 patients, 40 patients were boys and 37 patients were girls, with ages ranging from 2 years to 16 years (mean, 9.14 ± 3.4 years). All patients had a history of recently consuming unpasteurized milk or dairy products. Abdominal pain (58%) and arthralgia (%56), and myalgia (40%) were the most frequent complaints. The most frequent clinical findings were fever, arthritis, hepatomegaly, and splenomegaly. The seasonal distribution showed an increase in late spring and summer. All of the Brucella isolates were found to be B. melitensis biovar 3. Two isolates were resistant to ceftriaxone, while all isolates were susceptible to doxycycline, streptomycin and trimethoprim-sulfamethoxazole. Ranges of minimal inhibitory concentration (MIC) of tigecycline and rifampicin were 0.016-0.23 and 0.38-1.5 μg/ml, respectively. Molecular epidemiological analyzes revealed 42 different MLVA-16 profiles. Eighteen of these 42 profiles included two or more strains. The clustering rate was 66.7%. In three strains four locus variants, in one strain five locus variants were found. Bruce 30 was the highly discriminatory locus and it was followed by Bruce 16, Bruce 9, Bruce 7, and Bruce 4, respectively. All of the strains were defined as genotype 122 according to MLVA-11 and genotype 43 according to MLVA-8, and were in the Eastern Mediterranean genotype. In conclusion, brucellosis is still a significant public health problem in children in the region and high clustering rate indicates that most of the cases were related to each other and most probable originated from common source. Controlling of animal movements, meat and milk products and training activities about avoiding contaminated products of the children were necessary.