Investigation of the presence of Brucella spp. in amphibians collected from some regions in Türkiye

Abstract

Brucellosis is a zoonotic disease that causes economic losses in many countries worldwide, especially in livestock. With the development of molecular techniques, the diversity of Brucella species has been increasing in recent years. Recently, atypical Brucella spp. have been isolated mainly from cold-blooded animals. Firstly, the African bullfrog and then B. inopinata and B. microti-like strains have been identified in various frog species worldwide. This study aimed to determine the presence of Brucella in amphibian frogs for the first time in Türkiye by bacteriological and molecular methods. Internal organ samples (spleen, liver, lung, kidney, etc.) of 150 frogs from different regions of Türkiye (Edirne/Ipsala (53 pieces), Adıyaman/Kâhta (97 pieces)) were used for the isolation of Brucella spp. Simultaneously, DNA extraction was performed using a commercial isolation kit from tissue homogenates and samples cultured in media and left to incubation. As a result of Brucella genus-specific PCR (Polymerase Chain Reaction) and Multiplex PCR (Bruce-Ladder) methods performed with these extracts, no positivity was detected in the frog samples taken from Edirne province, while in 4 of the frog samples taken from Adıyaman province, bands of approximately 250, 600, 700, 1000, 1500 and 3000 bp were observed in Multiplex PCR. Sphingomonas paucimobilis (S. paucimobilis) was identified by analysing the culture obtained from these samples with VITEK®2:Healtcare. As a result, the presence of Brucella spp. could not be detected both bacteriologically and molecularly in the study samples. However, observing similar multiple bands in multiplex PCR suggested that this bacterium and Brucella species are phylogenetically close. At the same time, it was determined that this opportunistic pathogen isolated from various human infections can colonise amphibians. Since S. paucimobilis, which is found together with Brucella species under the class Alphaproteobacteria, causes opportunistic infections, especially in immunocompromised humans, it was concluded that this bacterium may pose a risk for those working in farms where frogs are raised for human consumption, and it is thought that it may be essential to take the necessary preventive measures.