Title : A biomolecular survey on the presence of zoonotic bacteria in troglophile bats in Sicily (Southern Italy)
Abstract:
Bats are mammals of the order Chiroptera that exhibit distinctive characteristics such as the ability to fly, a wide distribution, a long lifespan and diverse feeding strategies. They are important members of the ecosystem but also are natural reservoirs and carriers of numerous zoonotic bacteria and viruses, being immune to many of them. Humans are often in contact with bats in particular due to the anthropogenic alteration of their natural habitat which forces them to seek alternative sites and, consequently, to interact with other animals including domestic animals and humans. From this perspective, it is therefore essential for public health to know the pathogens carried by the bats.
In the present study, the results of a panel of biomolecular tests for bacterial agents Bartonella henselae, Borrelia spp., Coxiella burnetii, Leptospira spp., Chlamydia spp., Rickettsia spp. and Anaplasma phagocythopilum are shown. The analysis were carried out on oral swabs, oculoconjunctival swabs, urine and feces of insectivorous bats from 4 caves in the province of Ragusa and Syracuse (Sicily, Italy). The aim of the study was to evaluate the presence of potential zoonotic bacteria in different body habitats.
From December 2020 to April 2023, samples from 149 bats of 6 species, 4 guano samples and 16 bat ectoparasites were collected. Three oral swabs and 1 oculoconjunctival swab were positive for Bartonella henselae; 1 oral swab tested positive for Leptospira; 4 urine, 1 feces, 1 guano, 1 oral swab and 1 oculoconjunctival swab tested positive for Chlamydia spp. None of the tested samples showed positivity for Borrelia spp., Coxiella burnetii, Rickettsia spp. and Anaplasma phagocytophilum. The insects tested negative for all biomolecular test carried out. Zoonotic bacteria of which bats can be a reservoir were identified in the samples examined, in particular Chlamydia spp., Leptospira spp. and Bartonella henselae. Chlamydia was found in all body habitats, but more prominently in feces and urine than in oculoconjunctival and oral swabs. Concomitant detection of Chlamydia in multiple body habitats of the same individual could correspond to an acute infection. Zoonotic bacteria such as Bartonella henselae have also been detected in saliva.
Although transmission of Bartonella in bats is usually associated with arthropod vectors and droppings, these bacteria have also been found in the saliva of dogs and cats, suggesting that Bartonella may also be transmitted within bat populations through behaviours that result in transmission of saliva, such as biting and grooming. In conclusion, the results of the study provide a broader view of the bacterial species excreted within a throglophile bat community, highlight that bats can be reservoir of pathogens and furthermore show that, in addition to the examination of fecal samples, also saliva, ocular secretions and urine, due to the different microbiota, are useful for evaluating the potential role of bats as vectors of zoonotic infectious agents
Audience Take Away:
• The study provides new information on the role of bats in the spread of potentially pathogenic bacteria to humans. • The results suggest future studies on the bacterial community composition of different bat body habitats to evaluate potential transmission routes such as saliva, urine, eye secretions.
• Given the role of bats as potential carriers of zoonotic pathogens, the analysis of the interaction between microbiota and infection dynamics represents an important challenge.
