Comparison of Staphylococcus pettenkoferi Isolated from Human Clinical Cases and Cat Carriers Regarding Antibiotic Susceptibility and Biofilm Production

<i>Staphylococcus pettenkoferi (S. pettenkoferi)</i> is a rare opportunistic bacterium not commonly found in healthy individuals or animals<i>. S. pettenkoferi</i> has increasing clinical significance in both veterinary and human medicine due to its multidrug resistance and biofilm-forming ability. This study analyzed 12 isolates of <i>S. pettenkoferi</i> collected from humans and cats and identified them using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and <i>16S rRNA</i> and partial <i>rpo</i>B gene sequencing. All of the <i>S. pettenkoferi</i> were phenotypically resistant to penicillin, and almost all (except one human strain) were resistant to methicillin. Antibiotic susceptibility testing revealed a high prevalence of multidrug resistance in all human strains with frequent resistance to β-lactams, macrolides, and tetracyclines. A comparative analysis of human and feline isolates indicated the presence of shared resistance genes such as <i>blaZ</i>, <i>mecA</i>, and <i>ermA</i>. Biofilm production varied across isolates, with more potent biofilm formation abilities observed at elevated temperatures (39 °C) and time (48 h). These findings underscore the potential zoonotic risks of <i>S. pettenkoferi</i> and its role in managing multidrug-resistant infections.