Staphylococcus saprophyticus (S. saprophyticus) is an opportunistic coagulase-negative staphylococcus (CoNS) known to cause urinary tract infections in humans and is increasingly recognized in veterinary medicine. The aim of this study was to provide an epidemiological characterization of S. saprophyticus strains and to identify potential virulence factors that may contribute to interspecies transmission. This research is particularly important, as companion animals represent an understudied reservoir of this microorganism, and their role in the spread of resistant pathogens remains insufficiently understood. A total of 61 S. saprophyticus strains isolated from humans, dogs, and cats were analyzed. Identification was performed using MALDI-TOF MS and confirmed by PCR targeting the hrcA gene. Antimicrobial susceptibility was assessed using the disk diffusion and broth microdilution methods, while resistance genes were detected by PCR. The blaZ and mecA genes were present in all strains; additionally, the majority harbored the resistance genes ermA, ermB, tetM, and tetK. Multidrug resistance (MDR) was identified in 21/61 strains (34.4%). Biofilm-forming capacity was temperature-dependent, with the strongest biofilm production observed at 37 °C (70.5%). At 38 °C and 39 °C, the proportion of strong biofilm producers decreased to 50.8% and 52.5%, respectively. All tested strains demonstrated pathogenic potential in the Galleria mellonella larvae infection model, with the highest mortality recorded for selected feline and canine strains. These findings indicate that S. saprophyticus strains from both humans and companion animals possess notable virulence and multidrug resistance. The detection of genotypically and phenotypically resistant strains in animals highlights their potential role as reservoir for zoonotic transmission.

Staphylococcus saprophyticus (S. saprophyticus) is an opportunistic coagulase−negative staphylococcus (CoNS) known to cause urinary tract infections in humans and increasingly recognized in veterinary medicine. The aim of this study was to provide an epidemiological characterization of S. saprophyticus strains and to identify potential virulence factors that may contribute to interspecies transmission. This research is particularly important, as companion animals represent an understudied reservoir of this microorganism, and their role in the spread of resistant pathogens remains insufficiently understood. A total of 61 S. saprophyticus strains from humans, dogs and cats were analyzed. Identification was performed using MALDI –TOF MS and confirmed by PCR targetting the hrcA gene. Antimicrobial susceptibility was assessed using disk−diffusion and broth microdilution methods, while resistance genes were detected by PCR. The blaZ and mecA genes was present in all strains; additionally, the majority harbored resistance genes ermA, ermB, tetM, and tetK. Multidrug resistance (MDR) was identify in 21/61 strains (34.4%). Biofilm−forming capacity was temperature−dependent, with the strongest biofilm production observed at 37℃ (70.5%). At 38℃ and 39℃, the proportion of strong biofilm producers decreased to 50.8% and 52.5%, respectively. All testes strains demonstrated pathogenic potential in the Galleria mellonella larvae infection model, with the highest mortality recorded for selected feline and canine strains. These findings indicate that S. saprophyticus strains from both humans and companion animals possess notable virulence and multidrug resistance. The detection of genotypically and phenotypically resistant strains in animals highlights their potential role as reservoir for zoonotic transmission.

Fungi are a typical part of the microbiome of poultry houses, but some of the genera can be pathogenic for poultry and humans. An investigation was conducted on 200 duck eggs from 10 flocks to determine total fungal contamination on the eggshells. The colony types were identified morphologically and microscopically, and a representative group was identified using PCR. The resistance profiles for all obtained Aspergillus isolates were conducted. The dominating genera on eggshells were Penicillium, Alternaria and Aspergillus and the number of fungal colonies ranged from 0 to 7100. Aspergillus fumigatus was cultured from 9.5% eggshells, and all isolates were obtained from three flocks. The minimum inhibitory concentration (MIC) values for A. fumigatus isolates ranged from 0.094–32 μg/mL for amphotericin B (MIC 50 1 mg/L and MIC 90 32 μg/mL), 0.125–32 μg/mL for caspofungin (MIC 50 0.38 μg/mL and MIC 90 32 μg/mL), 0.19–32 μg/mL for itraconazole (MIC 50 1.5 μg/mL and MIC 90 32 μg/mL), 0.047–12 μg/mL for posaconazole (MIC 50 0.5 μg/mL and MIC 90 8 μg/mL) and 0.023–32 μg/mL for voriconazole (MIC 50 0.19 μg/mL and MIC 90 32 μg/mL). A total of 73.7% of the isolates were resistant to posaconazole and 68.4% to itraconazole. Nearly half of the strains (47.4%) showed resistance to amphotericin B and 31.6% to voriconazole. Because of the lack of antifungals registered for poultry, hygiene and the regular disinfection of litter in particular are needed to prevent the contamination of the eggs by fungi for both animal and human health.

Staphylococcus haemolyticus is an opportunistic coagulase-negative staphylococcus increasingly recognized as an important reservoir of antimicrobial resistance within the One Health framework. However, comparative studies simultaneously evaluating isolates from humans and companion animals remain limited. This study characterized 113 S. haemolyticus isolates recovered from clinically healthy and affected humans and cats and from clinically healthy dogs using phenotypic, molecular, proteomic, and genomic approaches. Multidrug resistance was identified in 45.13% (51/113) of isolates. Whole-genome sequencing of 35 selected isolates revealed substantial genomic diversity, with no clear clustering according to host species or clinical status within the analysed subset. The VFDB-associated loci tufA, clpC, and clpP were detected in all sequenced isolates; however, their presence does not imply expression or a direct contribution to virulence-related phenotypes. Acquired antimicrobial resistance determinants showed variable distributions across the analysed genomes. Within the WGS subset, mecA showed a host-associated difference that remained significant after false discovery rate correction in a one-isolate-per-host sensitivity analysis, whereas the initially observed association for blaZ/PC1-family determinants was not retained after this sensitivity analysis. No acquired resistance determinant was significantly associated with clinical status. Among the full collection of 113 isolates, blaZ (53.98%) and tetL (33.63%) were the most frequently detected resistance genes by PCR. Genotype–phenotype concordance varied according to the antimicrobial agent and phenotypic testing method, indicating that resistance-gene detection alone was not uniformly predictive of phenotypic susceptibility. Biofilm formation, assessed in all 113 isolates, increased markedly at 39 °C despite heterogeneous, strain-dependent changes in planktonic growth. Eight representative isolates evaluated in the Galleria mellonella model showed clear inoculum-dependent and strain-variable larval mortality; however, the assay was not designed to formally assess host-species- or clinical status-associated differences. Overall, the findings demonstrate substantial genomic and phenotypic overlap among human and companion-animal S. haemolyticus isolates, together with selected host-associated differences and marked strain-level variability, supporting the value of integrated One Health surveillance.

Staphylococcus epidermidis is an important opportunistic pathogen and a potential reservoir of antimicrobial resistance determinants, yet comparatively little is known about isolates originating from both humans and companion animals. This study characterized 320 S. epidermidis isolates obtained from humans, cats, and dogs within a One Health framework using phenotypic, molecular, proteomic, and genomic approaches. Antimicrobial susceptibility testing revealed high frequencies of resistance to oxacillin (67.19%), erythromycin (66.56%), tetracycline (55.63%), and clindamycin (53.75%) by disk diffusion. PCR-based analysis identified blaZ as the most prevalent resistance determinant (50.63%), whereas whole-genome sequencing of a selected subset revealed a broader and heterogeneous repertoire of resistance-associated genes. Among 67 sequenced isolates, 26 known sequence types were identified, including several STs occurring in isolates from more than one host species. Core-genome phylogenetic analysis demonstrated substantial genomic diversity without complete segregation according to host species or clinical status. Genotype–phenotype concordance was generally limited and gene dependent, and discrepancies were also observed between PCR- and WGS-based detection for selected resistance determinants. Biofilm formation was significantly influenced by incubation temperature, host species, and clinical status, while growth kinetics showed pronounced strain-specific variability and no consistent relationship with biofilm-forming capacity. MALDI-TOF MS profiling and partial rpoB phylogeny likewise showed considerable overlap among isolates from different host groups. In the Galleria mellonella infection model, mortality was inoculum dependent and varied substantially among strains. Overall, the findings demonstrate marked phenotypic and genomic heterogeneity among S. epidermidis isolated from humans and companion animals and indicate that some clonal backgrounds and resistance determinants occur across host species, highlighting the relevance of this species within a One Health context.