Impact of genetic diversity and antibiotic-resistance of Salmonella isolated from feral cats: One Health approach.

Free-living cats usually live in colonies in urban areas, especially close to parks and neighbourhoods where people feed them without any sanitary control. This can pose a human, animal and environmental health concern due to the close contact between uncontrolled colonies, the population and other domestic and/or wild animals. Thus, this study aimed to assess the genetic diversity and antimicrobial resistance (AMR) among Salmonella enterica subsp. enterica strains isolated from feral cats in a previous epidemiological study in the Gran Canaria island (Spain). A total of nineteen Salmonella isolates were obtained from November 2018 to January 2019 in a Salmonella epidemiological study in feral cats. All isolates obtained were genotyped by pulsed-field gel electrophoresis (PGFE) and were tested for antimicrobial susceptibility, in accordance with Decision 2013/652/EU. PFGE analysis revealed isolates clustering by serovar, with identical clones for serovars Bredeney and Grancanaria, while differing pulsotypes were observed for serovars Florida (88.89 % similarity) and Nima (83.23 % similarity). All but two isolates were resistant to at least one antimicrobial. The results obtained demonstrate that feral cats in the region investigated are a reservoir of Salmonella strains resistant to gentamicin (94.1 %) and of the critically important antimicrobial tigecycline (23.5 %). Hence, they could excrete AMR strains through their faeces and contaminate the environment, favoring the spread of such bacteria to cohabiting pets. Moreover, this widespread presence of AMR Salmonella clones across various serovars highlights the urgent need to implement efficient antimicrobial stewardship and control programs by the local governments due to the ongoing need to protect human and animal health under a One Health concept.

Research Note: Persistent Salmonella problems in slaughterhouses related to clones linked to poultry companies.

Salmonellosis remains one of the main foodborne zoonoses in Europe, with poultry products as the main source of human infections. The slaughterhouse has been identified as a potential source for Salmonella contamination of poultry meat. Despite the mandatory programme of the EU, there are companies with persistent Salmonella that are unable to remove the bacteria from their processing environment, compromising the entire production line. In this context, an intensive sampling study was conducted to investigate a slaughterhouse with persistent Salmonella problems, establishing the genetic relationship among Salmonella strains isolated during the slaughter process. A total of 36 broiler flocks were sampled during processing at the slaughterhouse. Salmonella was identified based on ISO 6579-1:2017 (Annex D), serotyped by Kauffman-White-Le-Minor technique, and the genetic relationship was assessed with ERIC-PCR followed by PFGE. The outcomes showed that 69.4% of the batches sampled carried Salmonella upon arrival at the slaughterhouse and that 46.3% of the different samples from carcasses were contaminated with Salmonella. The two serovars isolated at the different steps in the slaughterhouse were Enteritidis (98.2%) and Kentucky (1.8%). Pulsed-field gel electrophoresis analysis revealed a low genetic diversity, with all S. Enteritidis isolates showing a nearly identical pulsotype (similarity >85%) and S. Kentucky strains showed the same XbaI PFGE profile (95.0% genetic similarity). The results of this study showed a high genetic relationship among isolates recovered from carcasses and environmental samples in the slaughterhouse from both Salmonella-positive and Salmonella-free flocks. Salmonella strains re-circulated across to poultry flocks and re-entered the slaughterhouse to survive on the processing line. Thus, it is necessary to implement molecular diagnosis methods in time at the field level to determine the Salmonella epidemiology of the flock, to make rapid decisions for the control of Salmonella and prevent entry into the slaughterhouse environment.

Urban birds: An important source of antimicrobial resistant Salmonella strains in Central Spain.

Antimicrobial resistance (AMR) is one of the most important threats of the 21 st century. Wild birds have been described as reservoirs of AMR in different bacterial species, such as Salmonella spp. Privation of food, climate change and overpopulation have forced many wild species to modify their feeding habits, attending urban areas. In this context, the aim of this study was to study Salmonella presence, as well as related AMR in urban birds that inhabit the city and its surroundings. A total of 300 urban birds were sampled for Salmonella detection according to the ISO 6579-1:2017 (Annex D) recommendations, and serotyping was carried out according to the White-Kauffman-Le Minor scheme. Antimicrobial susceptibility was tested following 2013/652/EU Decision guides. Wild birds analysed were positive for Salmonella in 12.3 % of cases, with white storks fed in landfills as the most Salmonella prevalent species (p < 0.05). The most common serovars isolated were zoonotic (S. Enteritidis, S. Typhimurium and S. Typhimurium monophasic variant). From Salmonella isolated strains, 40.5 % were resistant to the most prevalent AMRs found in urban birds were ciprofloxacin (36.4 %), nalidixic acid (36.4 %) and colistin (27.3 %). The scientific community, public administration and population in general should work together to control antimicrobial administration and drug waste management in order to decrease the development and spread of AMR.