Genomic Characterization of Listeria monocytogenes and Other Listeria Species Isolated from Sea Turtles.

Listeria monocytogenes is a ubiquitous pathogen found both in the environment and food. It can cause listeriosis in a wide range of animals as well as in humans. Investigations on presence, spread and virulence are still limited to terrestrial and human environments. Embracing the One Health Approach, investigating the presence and spread of L. monocytogenes in marine ecosystems and among wildlife, would provide us with useful information for human health. This study investigated the presence of L. monocytogenes and Listeria spp. in two species of sea turtles common in the Mediterranean Sea (Caretta caretta and Chelonia mydas). A total of one hundred and sixty-four carcasses of sea turtles (C. caretta n = 161 and C. mydas n = 3) stranded along the Abruzzo, Molise, Campania, and Calabria coasts, were collected. Brain and fecal samples were taken, enriched, and cultured for the detection of Listeria spp. From the specimens collected, strains of L. monocytogenes (brain n = 1, brain and feces n = 1, multiorgan n = 1 and feces n = 1), L. innocua (feces n = 1 and brain n = 1), and L. ivanovii (brain n = 1) were isolated. Typical colonies were isolated for Whole Genome Sequencing (WGS). Virulence genes, disinfectants/metal resistance, and antimicrobial resistance were also investigated. L. monocytogenes, L. innocua, and L. ivanovii were detected in C. caretta, whilst only L. monocytogenes and L. innocua in C. mydas. Notable among the results is the lack of significant differences in gene distribution between human and sea turtle strains. Furthermore, potentially pathogenic strains of L. monocytogenes were found in sea turtles.

Identification of the Novel Streptococcus equi subsp. zooepidemicus Sequence Type 525 in Donkeys of Abruzzo Region, Italy.

Streptococcus equi sub. zooepidemicus (SEZ) is described as a commensal bacterium of several animal species, including humans. Growing evidence supports the potential role of SEZ in the onset and progression of severe clinical manifestations of diseases in horses and other animals. In the present communication, we describe the diagnostic procedure applied to characterize the streptococcal infections caused by a novel SEZ sequence type (ST525) in donkeys raised on a farm in Abruzzo, Italy. The diagnostic process began with anamnesis and anatomopathological analysis, which revealed a severe bacterial suppurative bronchopneumonia associated with systemic vascular damage and haemorrhages. Then, SEZ infection was confirmed by applying an integrative diagnostic strategy that included standard bacterial isolation techniques, analytical tools for bacteria identification (MALDI-TOF MS), and molecular analysis (qPCR). Furthermore, the application of the whole-genome sequencing approach helped us to identify the bacterial strains and the virulence factors involved in animal diseases. The novel SEZ-ST525 was identified in two cases of the disease. This new sequence type was isolated from the lung, liver, and spleen in Case 1, and from retropharyngeal lymph nodes in Case 2. Moreover, the presence of the virulence gene mf2, a virulence factor carried by prophages in Streptococcus pyogenes, was also found for the first time in an SEZ strain. The results of the present study highlight the need to apply an integrated diagnostic approach for the identification and tracking of pathogenic strains of SEZ, shedding new light on the re-evaluation of these bacteria as a causative agent of disease in animals and humans.

Severe Streptococcus equi Subspecies zooepidemicus Outbreak from Unpasteurized Dairy Product Consumption, Italy.

During November 2021-May 2022, we identified 37 clinical cases of Streptococcus equi subspecies zooepidemicus infections in central Italy. Epidemiologic investigations and whole-genome sequencing showed unpasteurized fresh dairy products were the outbreak source. Early diagnosis by using sequencing technology prevented the spread of life-threatening S. equi subsp. zooepidemicus infections.

First Report of Septicaemic Listeriosis in a Loggerhead Sea Turtle (Caretta caretta) Stranded along the Adriatic Coast: Strain Detection and Sequencing.

Although there are increasing reports on the prevalence of Listeria monocytogenes in wild species, this is the first case of listeriosis in sea turtle. An adult female Caretta caretta was rescued after being stranded alive along the coast of the Abruzzo region (Italy) in summer 2021. The turtle died in 6 days due to respiratory failure. The necropsy showed widespread organ lesions, such as yellow foci of necrosis in many organs, gastrointestinal erosions, pericarditis, and granulomatous pneumonia. Microbiological and histological analyses were performed on several organs. Listeria monocytogenes was isolated from multiple organs, indicating a case of septicaemic listeriosis, and the genome was sequenced and characterized. All the colonies analysed belonged to the same strain serogroup IVb, ST388, and CC388.

Co-Infection of L. monocytogenes and Toxoplasma gondii in a Sheep Flock Causing Abortion and Lamb Deaths.

Abortion in livestock is a public health burden, and the cause of economic losses for farmers. Abortion can be multifactorial, and a deep diagnostic investigation is important to reduce the spread of zoonotic disease and public health prevention. In our study, a multidisciplinary investigation was conducted to address the cause of increased abortion and lamb mortality on a farm, which detected a co-infection of Listeria monocytogenes and Toxoplasma gondii. Hence, it was possible to conclude that this was the reason for a reduced flock health status and the cause of an increased abortion rate. Furthermore, the investigation work and identification of the L. monocytogenes infection root allowed the reduction of economic loss.