Characteristic of <em>Staphylococcus saprophyticus</em> Isolated from Humans and Animals

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.