Periodontitis is a serious gum infection that damages the soft tissue and destroys the bone supporting the teeth. The aim of the study was to investigate the microbiota using traditional microbiology plating and metagenomic sequencing of extracted tooth alveoli in dogs with severe periodontitis. Isolation of culturable microorganisms was performed as part of bacteriological testing to provide bacteriological diagnosis to veterinary surgeons. Metagenomic sequencing was performed using shotgun sequencing on the Illumina HiSeq system platform. The most prevalent species at sites of periodontal infection detected by metagenomic sequencing were Porphyromonas gulae, Prevotella spp., Tannerella forsythia, Porphyromonas crevioricanis, Porphyromonas cangingivalis, and Bacteroides heparinolyticus. Pasteurella, Streptococcus, and Neisseria were the most frequently isolated culturable bacteria from infected sites detected by traditional microbiologic methods. Metagenomic data revealed that these three genera accounted for only 1.6% of all microbiota at the sites of infection. Antimicrobial resistance patterns of the isolated bacteria included resistance to ampicillin, doxycycline, sulfamethoxazole-trimethoprim, ciprofloxacin, colistin, cefotaxime, and chloramphenicol. Antimicrobial-resistant genes detected using shotgun sequencing also showed resistance to aminoglycosides and macrolides. Dogs with periodontal infections carry bacteria that can cause bite infections in humans as well as multi-resistant isolates. Therefore, treatment and prophylaxis or periodontal disease of dogs is important from a One Health perspective.

The oral microbiome of apex predators such as grey wolves (Canis lupus) is colonised by complex microbial communities and plays a crucial role in the health of wild mammals, but remains poorly understood. In this study, a single pooled sample mixed from oral samples of 17 wolves (Canis lupus) hunted in Lithuania was investigated for the determination of a variety of oral microbiota, providing the first metagenomic insight into wolf oral microbiomes in Baltic countries. The aim of this study was to identify the zoonotic and antimicrobial resistance potential of the oral microbiota. The results revealed diverse microbiomes associated with periodontal health as well as microbiomes related to the environment. Unique microbial taxa potentially reflect the nutritional and ecological interactions of carnivores. Shotgun metagenomic sequencing yielded a total of 18,726,406 raw reads, and following quality trimming and filtering, 86.01% of these (16,106,613) were retained. Among the total reads, 45.15% (8,455,255) were identified as host-derived and were removed. The most common oral bacterial genera were Pseudomonas (50%) and Psychrobacter (22.6%). Metagenomic reads for zoonotic pathogens, including Salmonella, Mycobacterium spp., Yersinia, Coxiella burnetii, Corynebacterium pseudotuberculosis, and others, were also detected, suggesting that grey wolves are potential natural reservoirs of zoonotic infections. Genes encoding antimicrobial resistance to many classes of antibiotics were also detected. This research contributes to understanding wolf dietary habits, oral health, the carriage and possible risk of transmitting AMR, and social interactions.

Walnut septum (WS), a major by-product of walnut processing, represents a promising source of bioactive compounds with potential antioxidant and antimicrobial properties. This study aimed to characterise the phytochemical composition of WS extracts from different habitat origins and evaluate their antimicrobial activity. Total amino acids were profiled by gas chromatography–mass spectrometry, while phenolic compounds were analysed using high-performance liquid chromatography. Both methods were evaluated according to ICH Q2 (R2) guidelines for analytical procedure validation. The results showed a complex composition of amino acids and polyphenols, including ellagic acid and quercitrin. However, it was clear that habitat variations in WS samples had a significant impact on the quantities and composition of phenolic compounds and total amino acids in WS extracts. Antimicrobial activity was assessed against Gram-positive and Gram-negative bacterial strains. Variations in antimicrobial efficacy were associated with differences in phenolic composition and content due to habitat differences in WS sample origins. Collectively, this study highlights the WS as a valuable agro-industrial by-product with potential applications as a natural source of antimicrobial compounds in food and pharmaceutical systems.

Canine periodontitis is one of the most prevalent chronic diseases for dogs over two years of age. Periodontal pockets may serve as a reservoir for opportunistic bacteria including Pasteurella stomatis, Neisseria animaloris, and Streptococcus canis; however, data on their antimicrobial susceptibility and potential One Health relevance remain limited. This pilot study investigated culturable bacterial isolates recovered from periodontal pockets of dogs with different stages of periodontal disease. Subgingival samples were collected under general anesthesia after periodontal probing and dental radiographic assessment during routine comprehensive oral health assessment and treatment (COHAT) procedures. Bacterial isolates were cultured, identified using MALDI-TOF MS, and tested for minimum inhibitory concentrations (MIC) against amoxicillin (AML), doxycycline (DX), trimethoprim–sulfamethoxazole (SXT), gentamicin (CN), chloramphenicol (C), and ciprofloxacin (CIP). In total, 122 isolates from 101 dogs were analyzed, including Pasteurella stomatis (n = 54), Neisseria animaloris (n = 33), and Streptococcus canis (n = 35). MIC distributions varied between bacterial species and antimicrobial agents, while interpretation was limited by the lack of species-specific veterinary medicine breakpoints for some isolates. These preliminary findings highlight the need for larger standardized studies to support antimicrobial resistance surveillance in canine oral microbiota.