Molecular Evidence of Bartonella spp. in Rodents: A Study in Pianosa Island, Italy

Simple Summary: Invasive rats and field mice were captured under the project RESTO CON LIFE Island conservation in Tuscany, restoring habitat not only for birds, aiming to improve habitats preservation on the Italian islands of Pianosa, Elba, Montecristo, and Giannutri. Bartonella henselae DNA was detected in one captured animal. This is the first report of the presence of B. henselae DNA in rodents in Italy. B. henselae is the causative agent of cat scratch disease, and the detection of this bacterium in rodents might have public health implications. Wild rodents are reservoirs of several Bartonella species that cause human bartonellosis. The aim of this study was to assess the presence of Bartonella spp. DNA in wild rodents in Pianosa island, Italy. Rats (Rattus spp.; n = 15) and field mice (Apodemus spp.; n = 16) were captured and spleen DNA tested for the presence of Bartonella spp. by means of an initial screening using a qPCR amplifying a short segment of the 16S-23S rRNA gene intergenic transcribed spacer region (ITS, similar to 200 bp) followed by conventional PCR amplification of a longer ITS fragment (similar to 600 bp) and of a citrate synthase (gltA, similar to 340 bp) gene segment. A total of 25 spleen DNA samples obtained from 31 rodent carcasses (81%) yielded positive qPCR results. Bartonella genus was confirmed by amplicon sequencing. By conventional PCR, eight out of 25 samples (32%) yielded bands on gels consistent with ITS segment, and 6/25 (24%) yielded bands consistent with the gltA locus. Amplicon sequencing identified B. henselae and B. coopersplainsensis in 1/25 (4%), and 4/25 (16%) samples, respectively. Moreover, 5/25 (20%) of Bartonella spp. positive samples showed gltA sequences with about 97% identity to B. grahamii. These results provide support to recently published observations suggesting that B. henselae circulates in wild rodent populations.