Novel Borrelia genotypes in bats from the Macaregua Cave, Colombia

Bats have been implicated as reservoirs of relapsing fever group spirochaetes since the beginning of the last century. Recently, bat-associated spirochaetes have been reported as human pathogens. In 1968, a spirochaete was detected in blood of the bat Natalus tumidirostris captured inside the Macaregua cave, Colombia. Data on this microorganism were never published again. The aim of this study was to evaluate the presence of Borrelia DNA in blood from bats of Macaregua cave. We performed molecular analyses using a genus-specific real-time PCR targeting the 16S rRNA to detect DNA of Borrelia in blood samples from 46 bats captured in the Macaregua cave. Positive samples were submitted to a battery of PCRs aiming to amply Borrelia 16S rRNA, flaB, glpQ, p66, ospC, clpA, clpX, nifS, pepX, pyrG, recG, rplB and uvrA genes. Seventeen samples were positive for Borrelia after real-time PCR. With the exception of flaB gene, attempts to amplify further loci were unsuccessful. Nucleotide and amino acid divergences of four flaB haplotypes characterized from blood of Carollia perspicillata showed Borrelia burgdorferi sensu lato (Bbsl) as the most closely related group. A phylogenetic tree including 74 sequences of the genus confirmed this trend, since Borrelia genotypes detected in bats from Macaregua formed a monophyletic group basally positioned to Bbsl. Our results suggest that Borrelia genotypes characterized from bats roosting in the Macaregua cave might constitute a new taxon within the genus. This is the first molecular characterization of a Borrelia sp. in Colombia.

Automated summary

Bats have been regarded as reservoirs of relapsing fever group spirochaetes for over a century, and recently bat-associated spirochaetes have been identified as human pathogens. This study in Colombia's Macaregua cave found Borrelia DNA in blood samples from bats, suggesting the possibility of a new taxon within the genus. Further analysis revealed a phylogenetic relationship to Borrelia burgdorferi sensu lato (Bbsl).