Molecular Typing of Pathogenic Leptospira Species Isolated from Wild Mammal Reservoirs in Sardinia

SIMPLE SUMMARY: Leptospirosis is caused by pathogenic spirochaetes of the genus Leptospira. Humans can become infected with these bacteria through direct contact with urine from infected animals or indirectly through interaction with a urine contaminated environment. Among wildlife species, rodents are considered the primary reservoir hosts for leptospirosis in rural and urban environments. Epidemiological data, regarding leptospirosis in various wild species in Europe, suggest that these animals play a different role in leptospiral persistence. Unfortunately, studies on the presence and typing of Leptospira species in wild mammals are lacking in Sardinia. The aim of the present study was to investigate the prevalence of Leptospira species in wild mammals. Kidneys collected from carcasses were analyzed by culture and molecular testing. Greater positivity was found in hedgehogs, followed by weasels and rodents. The results obtained suggest that Sardinian fauna may play a possible sentinel role in the transmission cycle of leptospirosis to humans. Gathering this information in different wildlife species is crucial for better understanding of the epidemiology of leptospirosis and for the development of appropriate prevention measures. ABSTRACT: Leptospirosis is a global zoonosis caused by pathogenic species of Leptospira that infect a large spectrum of domestic and wild animals. This study is the first molecular identification, characterization, and phylogeny of Leptospira strains with veterinary and zoonotic impact in Sardinian wild hosts. All samples collected were cultured and analyzed by multiplex real time polymerase chain reaction (qPCR). Sequencing, phylogenetic analyses (based on rrs and secY sequences), and Multilocus Sequence Typing (MLST) based on the analysis of seven concatenated loci were also performed. Results revealed the detection of Leptospira DNA and cultured isolates in 21% and 4% of the samples examined, respectively. Sequence analysis of Leptospira positive samples highlighted the presence of the interrogans and borgpetersenii genospecies that grouped in strongly supported monophyletic clades. MLST analyses identified six different Sequence Types (ST) that clustered in two monophyletic groups specific for Leptospira interrogans, and L. borgpetersenii. This study provided about the prevalence of leptospires in wild mammals in Sardinia, and increased our knowledge of this pathogen on the island. Monitoring Leptospira strains circulating in Sardinia will help clinicians and veterinarians develop strategic plans for the prevention and control of leptospiral infections.