Clinically healthy household dogs and cats as carriers of multidrug-resistant Salmonella enterica with variable R plasmids.

Introduction. Antimicrobial resistance (AMR) is a One Health issue concerning humans, animals and the environment and a unified One Health approach is required to contain this problematic issue. Dogs and cats are popular pet animals and are known to carry many bacterial pathogens that are of public health importance, including Salmonella. However, data on AMR in companion animals is limited.Gap statement. Scant AMR data from bacteria originating from companion animals limits an accurate assessment of the impacts of pet-animal-related AMR on public health.Purpose. This study aimed to phenotypically and genetically investigate AMR in Salmonella isolated from pet dogs and cats in Thailand.Methodology. Salmonella enterica were isolated from pet dogs (n=159) and cats (n=19) in Thailand between 2016 and 2019. All isolates were serotyped. Phenotypic and genotypic antimicrobial resistance was examined. PCR-based replicon typing, replicon sequence typing and plasmid multilocus sequence typing were conducted to characterize plasmids.Results. Seventy-seven serovars were identified, with serovars Weltevreden (9.6%) and Stockholm (9.0%) the most common. Most of the isolates (34.3%) were multidrug-resistant. The serovar Stockholm was an ESBL-producer and carried the ß-lactamase genes bla TEM-1 and bla CTX-M-55. The plasmid-mediated quinolone resistance (PMQR) gene, qnrS, was also detected (10.1%). Class 1 integrons carrying the dfrA12-aadA2 cassette array were most frequent (45.9%). Five plasmid replicon types as IncA/C (0.6%), N (1.1%), IncFIIA (28.7%), IncHI1 (2.2%), and IncI1 (3.4%) were identified. Based on the pMLST typing scheme (n=9), plasmids were assigned into five different STs including IncA/C-ST6 (n=1), IncH1-ST16 (n=4), IncI1-ST3 (n=1), IncI1-ST60 (n=1) and IncI1-ST136 (n=1). The ST 16 of IncHI1 plasmid was a novel plasmid ST. Subtyping F-type plasmids using the RST scheme (n=9) revealed four different combinations of replicons including S1:A-:B- (n=4), S1:A-:B22 (n=2), S3:A-:B- (n=1) and S-:A-:B47 (n=1).Conclusions. Our findings highlight the role of clinically healthy household dogs and cats as carriers of AMR Salmonella strains with different R plasmid. The implementation of AMR phenotypes instigation and genotypic monitoring and surveillance programmes in companion animals are imperative as integral components of the One Health framework.

Evaluation of the Containment of Antimicrobial-Resistant Salmonella Species from a Hazard Analysis and Critical Control Point (HACCP) and a Non-HACCP Pig Slaughterhouses in Northeast Thailand.

To evaluate the containment of antimicrobial-resistant (AMR) Salmonella contaminations of a HACCP slaughterhouse (HACCP SH) and a non-HACCP slaughterhouse (non-HACCPSH), 360 paired pig rectal (representing the farm pig status) and carcass samples (representing the contamination) were collected equally from the two slaughterhouses that serviced 6 and 12 farms, respectively, in Northeast Thailand (n = 720). The purified Salmonella isolates were serotype identified, antimicrobial susceptibility tested, and pulsed-field gel electrophoresis (PFGE) assessed. Four evaluations of two slaughterhouses were examined: (1) the means of slaughtering contamination rates (SCR) (to evaluate the contamination level by averaged farm SCRs): the HACCP SH decreased contamination (SCR: -48.89% ± 8.80%, n = 6), whereas the non-HACCP SH increased (SCR: 14.31% ± 9.35%, n = 12). (2) The serotype diversity: the HACCP SH decreased the diversity from the rectal group (110 isolates, 9 serotypes) to carcass group (23 isolates, 3 serotypes), whereas there was no decrease in the non-HACCP SH (rectal group (66 isolates, 14 serotypes) and carcass group (31 isolates, 10 serotypes)). (3) The AMR patterns: the HACCP SH decreased from rectal group (96 isolates, 7 patterns) to carcass group (22 isolates, 1 pattern), whereas there was no decrease from the non-HACCP SH rectal group (22 isolates, 7 patterns) to carcass group (48 isolates, 8 patterns). (4) The estimated indirect contamination rate (by serotype screening and PFGE confirmation): the HACCP SH was 60.87% (14/23), whereas the non-HACCP SH was 98.48% (65/66). This study indicates that both the slaughterhouses keep a high level of indirect contamination; the HACCP SH decreases Salmonella contaminations and reduces the AMR patterns, the non-HACCP SH increases contaminations.

Molecular epidemiology and antimicrobial resistance of Salmonella isolates from broilers and pigs in Thailand.

AIMS: This study aimed to determine the prevalence and antimicrobial resistance pattern of Salmonella spp., and the genetic relatedness between isolates from broilers and pigs at slaughterhouses in Thailand. MATERIALS AND METHODS: Fecal samples (604 broilers and 562 pigs) were collected from slaughterhouses from April to July 2018. Salmonella spp. were isolated and identified according to the ISO 6579:2002. Salmonella-positive isolates were identified using serotyping and challenged with nine antimicrobial agents: Amoxicillin/clavulanate (AMC, 30 µg), ampicillin (AMP, 10 µg), ceftazidime (30 µg), chloramphenicol (30 µg), ciprofloxacin (CIP, 5 µg), nalidixic acid (NAL, 30 µg), norfloxacin (10 µg), trimethoprim/sulfamethoxazole (SXT, 25 µg), and tetracycline (TET, 30 µg). Isolates of the predominant serovar Salmonella Typhimurium were examined for genetic relatedness using pulsed-field gel electrophoresis (PFGE). RESULTS: Salmonella was detected in 18.05% of broiler isolates and 37.54% of pig isolates. The most common serovars were Kentucky, Give, and Typhimurium in broilers and Rissen, Typhimurium, and Weltevreden in pigs. Among broilers, isolates were most commonly resistant to antibiotics, NAL, AMP, TET, AMC, and CIP. Pig isolates most commonly exhibited antimicrobial resistance against AMP, TET, and SXT. Based on PFGE results among 52 S. Typhimurium isolates from broilers and pigs, a high genetic relatedness between broiler and pig isolates (85% similarity) in Cluster A and C from PFGE result was identified. CONCLUSION: The results revealed high cross-contamination between these two animal species across various provinces in Thailand.