Biomolecular Investigation of Bartonella spp. in Wild Rodents of Two Swiss Regions.

Sara Divari,Enrico Bollo,Nicole Borel,Giovanni Ghielmetti,Marta Danelli,Paola Pregel

doi:10.3390/pathogens10101331

Abstract

Rodents represent a natural reservoir of several Bartonella species, including zoonotic ones. In this study, small wild rodents, collected from two sites in rural areas of Switzerland, were screened for Bartonella spp. using molecular detection methods. In brief, 346 rodents were trapped in two rural sites in the Gantrisch Nature Park of Switzerland (Plasselb, canton of Fribourg, and Riggisberg, canton of Bern). Pools of DNA originating from three animals were tested through a qPCR screening and an end-point PCR, amplifying the 16S-23S rRNA gene intergenic transcribed spacer region and citrate synthase (gltA) loci, respectively. Subsequently, DNA was extracted from spleen samples belonging to single animals of gltA positive pools, and gltA and RNA polymerase subunit beta (rpoB) were detected by end-point PCR. Based on PCR results and sequencing, the prevalence of infection with Bartonella spp. in captured rodents, was 21.10% (73/346): 31.78% in Apodemus sp. (41/129), 10.47% in Arvicola scherman (9/86), 17.05% in Myodes glareolus (22/129), and 50% in Microtus agrestis (1/2). A significant association was observed between Bartonella spp. infection and rodent species (p < 0.01) and between trapping regions and positivity to Bartonella spp. infection (p < 0.001). Similarly, prevalence of Bartonella DNA was higher (p < 0.001) in rodents trapped in woodland areas (66/257, 25.68%) compared to those captured in open fields (9/89, 10.11%). Sequencing and phylogenetic analysis demonstrated that the extracted Bartonella DNA belonged mainly to B. taylorii and also to Candidatus “Bartonella rudakovii”, B. grahamii, B. doshiae, and B. birtlesii. In conclusion, the present study could rise public health issues regarding Bartonella infection in rodents in Switzerland.

Highlights

Bartonella species are Gram-negative, facultative intracellular and emerging zoonotic bacteria infecting both domestic and wild mammals [1]
Sequencing and phylogenetic analysis demonstrated that the extracted Bartonella DNA belonged mainly to B. taylorii and to Candidatus “Bartonella rudakovii”, B. grahamii, B. doshiae, and B. birtlesii
Prevalence recorded for Bartonella spp. in Apodemus sp. was 31.78% (41/129): 39/129 animals tested were positive for both gltA and RNA polymerase subunit beta (rpoB) loci by conventional PCR (cPCR) and 2/129 positive only for rpoB locus

Summary

Introduction

Bartonella species are Gram-negative, facultative intracellular and emerging zoonotic bacteria infecting both domestic and wild mammals [1]. Bartonella infection often leads to febrile illnesses and the clinical condition may be similar to those triggered by other pathogens (e.g., Borrelia spp.) [8]. This suggests that the diseases associated to Bartonella could be under-estimated. The number of newly detected Bartonella species increased significantly and, to date, 45 different species have been isolated [9] These were identified in humans, domestic [10,11,12] and wild animals, including bats [13], deer [14], marine mammals [15], rodents [16], and sheep [17]. Molecular evidence of Bartonella spp. was reported in some migratory bird species and sea turtles [18,19]

Methods

Results

Conclusion