Detection of Chlamydial DNA from Mediterranean Loggerhead Sea Turtles in Southern Italy

SIMPLE SUMMARY: Chlamydiae are ubiquitous in animals, particularly in wildlife. Some chlamydial species additionally represent a potential risk for public health, as they have been associated with severe diseases in humans. Chlamydial agents have been detected in several groups of reptiles, but these animals do not always show signs of disease. Therefore, the present study aimed at investigating the presence of chlamydial DNA in samples collected from asymptomatic Mediterranean loggerhead sea turtles, after rehabilitation in a research centre in southern Italy. The molecular analyses resulted in the extensive presence of chlamydial DNA in the examined samples, suggesting that sea turtles might host these microorganisms as opportunistic flora, and potentially disseminate them. Despite the impossibility to identify the chlamydial species involved, this study emphasizes the importance of chlamydiae in sea turtles and motivates further studies to fully understand these agents, especially in relation to wildlife conservation and potential impacts on animal and public health. ABSTRACT: Chlamydiae are obligate intracellular bacteria that include pathogens of human and veterinary importance. Several reptiles were reported to host chlamydial agents, but pathogenicity in these animals still needs clarification. Given that only one report of chlamydiosis was described in sea turtles, and that chlamydiae might also be detected in hosts without clinical signs, the current study examined asymptomatic Mediterranean loggerhead sea turtles for the presence of chlamydial DNA. Twenty loggerhead sea turtles, rehabilitated at the Marine Turtle Research Centre (Portici, Italy), were examined collecting ocular-conjunctival, oropharyngeal and nasal swabs. Samples were processed through quantitative and conventional PCR analyses to identify Chlamydiales and Chlamydiaceae, with particular attention to C. pecorum, C. pneumoniae, C. psittaci, and C. trachomatis. Although it was not possible to determine the species of chlamydiae involved, the detection of chlamydial DNA from the collected samples suggests that these microorganisms might act as opportunistic pathogens, and underlines the role of sea turtles as potential carriers. This study highlights the presence of chlamydial agents in sea turtles, and encourages further research to fully characterize these microorganisms, in order to improve the management of the health and conservation of these endangered species, and prevent potential zoonotic implications.