Zoonotic bacteria and vector-borne protozoa in troglophilus bat colonies in Sicily (Southern Italy): a biomolecular survey

Bats, as members of the order Chiroptera, are vital to ecosystems and serve as reservoirs for numerous microorganisms, some of which can cause zoonotic diseases. Human interactions with bats are increasing due to habitat alterations, making it essential to understand their microbiota, particularly potential pathogens. This study aimed to evaluate the excretion of zoonotic bacteria in insectivorous bats from four caves in the provinces of Ragusa, Catania and Syracuse (Sicily, Southern Italy) using molecular biology tests for zoonotic agents, including Bartonella henselae, Borrelia, Coxiella burnetii, Leptospira, Chlamydia, Rickettsia, Anaplasma and Piroplasmids. From December 2020 to April 2023, urine, fecal swabs, ocular conjunctival swabs and oropharyngeal swabs were collected from 149 bats of six species, along with guano samples from the caves. Bartonella henselae DNA was detected in 3 of the 149 tested bats, one ocular conjunctival swab and two oropharyngeal swabs. Chlamydia spp. DNA was detected in a sample of guano, in feces, ocular conjunctival and oropharyngeal swabs of a bat and in four urine samples. Piroplasmids DNA was detected in 10 of 149 fecal swabs and in 5 of 16 bat ectoparasites. No samples were positive for Leptospira spp., Borrelia spp., Coxiella burnetii, Rickettsia spp., or Anaplasma spp. These findings underscore the importance of multiple sample types in assessing bats as reservoirs for zoonotic pathogens, particularly highlighting their role in transmitting pathogens through various body habitats, including saliva, urine, and ocular excretions. This research highlights the relevance of monitoring bat populations and studying their microbiota to enhance protections for both human and animal health.