Background/Objectives: Klebsiella (K.) pneumoniae is a significant pathogen in both humans and animals. However, data on its occurrence in animals in Germany remain limited. This study aimed to investigate the antimicrobial resistance (AMR) phenotypes, AMR genes, and virulence traits of animal-derived K. pneumoniae isolates from Germany. Methods: A total of 59 K. pneumoniae isolates obtained in 2023 from dogs, cats, horses, cattle, and chickens across 11 German federal states were analysed. Phenotypic antimicrobial susceptibility testing (AST) was performed, and whole-genome sequencing (WGS) was used for genomic characterisation, including detection of AMR genes, virulence-associated genes, sequence types (STs), and plasmid replicons. Results: Most isolates (78%) were susceptible to all tested antibiotics, while three isolates were classified as multidrug-resistant (MDR). Resistance was most frequently observed for piperacillin (n = 8) and trimethoprim/sulfamethoxazole (n = 4). Carbapenem resistance was detected in two isolates (one from a dog and one from a cat), and phenotypic colistin resistance in one dog isolate. WGS identified 96 AMR genes across isolates, with 20-42 AMR determinants per isolate, conferring resistance to β-lactams, aminoglycosides, fluoroquinolones, sulfonamides, tetracyclines, trimethoprim, and fosfomycin. Ten extended-spectrum β-lactamase (ESBL)-producing isolates carried genes including blaCTX-M-15, blaSHV-2, blaSHV-27, blaSHV-42, blaSHV-106, and blaTEM-158. Although fosA was detected in all isolates, only three exhibited phenotypic resistance to fosfomycin. A total of 52 STs were identified, including high-risk clones. One hypervirulent isolate (ST60) carrying hypervirulence-associated genes rmpA and iroB was detected. Plasmid replicons were present in 70% of isolates, while plasmid-associated AMR genes were identified in nine isolates. Conclusions: This study demonstrates the genomic diversity of K. pneumoniae identified in companion animals and highlights the presence of AMR and virulence determinants relevant to a One Health context.
Canine enteric viruses are an important cause of gastrointestinal disease in pet dogs worldwide. Routine diagnosis often relies on pathogen-specific PCR assays, which may fail to detect some viruses, particularly neglected pathogens or genetically divergent variants of established threats. This limits both clinical characterization of affected patients and broader understanding of disease ecology. To address these limitations, we applied metagenomics and a viral discovery bioinformatics pipeline to faecal samples from diarrhoeic dogs in the UK that had been submitted routinely for PCR-based diagnostic testing. Across 80 dogs, we identified 12 viruses known to infect canids, 9 of which have not previously been reported in UK dogs. Among these, several taxa with prior associations to gastrointestinal disease were identified, including canine sapovirus and canine minute virus. By contrast, for other viruses newly detected in the UK, including bufavirus and rotavirus C, clinical relevance in dogs remains unclear. Notably, an identified protoparvovirus fell within the same species as human-canine-associated parvovirus 1, a recently described lineage detected in both canine and human oropharyngeal samples. We also identified a canine parvovirus 2 strain that clustered with a predominantly wildlife-associated lineage, consistent with occasional exposure at the domestic-wildlife interface rather than established circulation in dogs. These two detections illustrate how genome-level surveillance can help prioritize viruses for targeted investigation of host range and transmission context. Overall, these data broaden the catalogue of viruses associated with diarrhoeic dogs in the UK and support periodic review of diagnostic targets informed by viral metagenomic surveillance, while highlighting the need for controlled studies to assess causality and clinical relevance.
Palmoplantar keratoderma in humans is a condition defined by an abnormally thickened cornified skin layer on the hands and feet. In animals, the corresponding disease is commonly termed paw pad hyperkeratosis. It can be acquired due to repeated trauma, infections, cancer, or inflammatory dermatoses, or inherited due to pathogenic variants in genes involved in skin development. More than 60 different genes involved in the development of palmoplantar keratoderma have been described. Here, we investigated a female Labrador Retriever showing hyperkeratosis on all four paw pads and most digital pads. Histologically, the stratum corneum was expanded by predominantly orthokeratotic hyperkeratosis with occasional mild parakeratotic areas. DNA of the affected dog was isolated from EDTA-blood and whole genome sequencing was performed. Comparison of the whole genome sequencing data to 1664 unaffected control dogs revealed a private de novo heterozygous missense variant in the GJB6 gene which was not present in the parents. GJB6 encodes connexin 30, a subunit of the desmosome. In humans, pathogenic variants in this gene cause isolated deafness or Clouston syndrome, an autosomal dominant condition that is characterized by alopecia, nail dystrophy, and palmoplantar hyperkeratosis. The paw pad hyperkeratosis phenotype in the investigated dog shows similarities to Clouston syndrome and strongly suggests that the GJB6 missense variant is responsible for its condition. However, our investigation also highlights differences between human and dog that could provide deeper insights into the function of GJB6.
Osteosarcoma (OSA) is the most common primary bone tumor in dogs and cats, and accurate diagnosis of OSA has therapeutic and prognostic implications. Immunohistochemistry targeting osterix (Osx), a transcription factor expressed in osteoblasts, was applied to 80 canine samples (40 OSAs and 40 controls (8 chondrosarcomas, 8 fibrosarcomas, 8 hemangiosarcomas, 8 histiocytic sarcomas, and 8 malignant melanomas)) and 40 feline samples (20 OSAs and 20 controls (5 fibrosarcomas, 5 hemangiosarcomas, 5 chondrosarcomas, 3 malignant melanomas, and 2 histiocytic sarcomas)), diagnosed histologically. All 120 samples were assessed blinded using a previously established semiquantitative scoring and classification system. In dogs, 37/40 OSAs (true positives, sensitivity 92.5%) and 2/40 controls (false positives, specificity 95.0%) were classified as OSA. In cats, 14/20 OSAs (true positives, sensitivity 70.0%) and 5/20 controls (false positives, specificity 75.0%) were classified as OSA. Tumors most often "misclassified" as OSAs were chondrosarcomas in both dogs (2/8) and cats (4/5). In 4 cases for which paired decalcified and nondecalcified samples of the same OSA were available, decalcification of OSAs did not affect classification. Quiescent canine, feline, and murine osteoblasts and canine reactive, metaplastic, and non-OSA neoplastic osseous conditions were also tested and demonstrated Osx immunoreactivity; avian and piscine osteoblasts did not. In conclusion, Osx is a highly sensitive and specific marker of canine OSA and a moderately sensitive and specific marker of feline OSA. The diagnostic algorithm applied in this study is a useful adjunctive tool in the diagnosis of canine OSA.
Abstract A 15‐year‐old, female, domestic shorthaired cat presented with a small, red, bilobulated pedunculated mass attached to the anterior surface of the left third eyelid in addition to red discoloration of the left upper and lower eyelids in the region of the medial canthus. Histopathology and immunohistochemistry were consistent with conjunctival haemangiosarcoma and conjunctival/cutaneous haemangiosarcoma of the third eyelid and eyelids, respectively. Haemangiosarcoma of the third eyelid has been described in three cats historically, with no recurrence following complete excision in two cases and unknown outcome in the case of incomplete excision. This report describes the case's diagnosis, treatment and post‐operative outcome.
