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Introduction. Wild animals are one of the putative reservoirs of antimicrobial-resistant bacteria, but the significance of raccoon dogs remains to be investigated. Hypothesis. Raccoon dogs can be a reservoir of antimicrobial-resistant bacteria. Aim. This study aimed to explore the prevalence of antimicrobial resistance, mainly extended-spectrum cephalosporins resistance, in Escherichia coli isolates from faeces of 80 Japanese raccoon dogs in Kanagawa Prefecture, Japan. Methodology. All of the 80 faecal samples were streaked onto deoxycholate-hydrogen sulfate-lactose (DHL) and cefotaxime (CTX)-supplemented DHL (DHL-CTX) agars. Susceptibilities to ten antimicrobials were determined using the agar dilution method. Additionally, extended-spectrum β-lactamases (ESBLs) and AmpC-type β-lactamases (ABLs) were identified in addition to sequence types (STs), in ESC-resistant isolates by a polymerase chain reaction and sequencing. Results. Out of all the samples, 75 (93.8 %) and 20 (25.0 %) E. coli isolates were isolated by DHL and DHL-CTX agars, respectively. Significantly higher resistance rates to most of the drugs were found in DHL-CTX-derived isolates than DHL-derived isolates (Pn=6), CTX-M-2 (n=2), CTX-M-1 (n=1) and CTX-M-55 (n=1) as ESBLs, and CMY-2 (n=8) and DHA-1 (n=1) as ABLs in 20 DHL-CTX-derived isolates. Most of the detected STs were related to Japanese humans (i.e. ST10, ST58, ST69, ST131, ST357, ST648 and ST4038). Notably, this is the first report on ST69, ST131, ST155 and ST648, which are well-known international high-risk clones in Japanese raccoon dogs. Conclusion. Our findings underscore the need to understand the significance of raccoon dogs as an antimicrobial-resistant bacteria reservoir using one health approach.

Sarcoptes scabiei (Acari: Sarcoptidae) causes a common contagious skin disease that affects many mammals. Here, the complete mitochondrial genome of a mite, S. scabiei var. nyctereutis, from Japanese wild raccoon dogs was analyzed. The 13,837bp circular genome contained 13 protein-coding genes, two rRNA genes, and 22 tRNA genes. For the first time, two tRNAs (alanine and tyrosine), that were thought to be absent in scabies mites from other animals, were predicted to have short, non-cloverleaf structures by in silico annotation and detected by RT-PCR, sequencing, and northern analysis. The mitochondrial genome structure of S. scabiei is similar to that of Psoroptes cuniculi and Dermatophagoides farinae. While small and unusual tRNA genes seem to be common among acariform mites, further experimental evidence for their presence is needed. Furthermore, through an analysis of the cox1 gene, we have provided new evidence to confirm the transmission of this mite between different animal hosts.

Scabies is a highly contagious skin disease caused by the mite Sarcoptes scabiei that affects many mammals. However, the sensitivity of traditional tests for scabies diagnosis in humans is less than 50%. To simplify the diagnosis of scabies, methods that are simple, sensitive, specific, and cost-effective are required. We developed an immunodiagnostic test based on S. scabiei var. nyctereutis RNA-seq data collected from Japanese raccoon dogs with sarcoptic mange. Three candidate antigens—a highly expressed hypothetical protein “QR98_0091190,” another mite allergen known as “SMIPP-Cc,” and an abundant “vitellogenin-like protein”—were evaluated by western-blot analysis. A lateral flow immunoassay, using specific antibodies against the vitellogenin-like protein, successfully detected scabies in the skin flakes of S. scabiei-infected raccoon dogs. This assay can potentially diagnose scabies more accurately in wildlife, as well as in humans.