Insights into the Virulence and Antimicrobial Resistance of <i>Staphylococcus hyicus</i> Isolates from Spanish Swine Farms

Abstract

Staphylococcus hyicus is a significant pathogen in swine, primarily causing exudative epidermitis. Addressing S. hyicus infections requires both the characterization of virulence and antimicrobial resistance (AMR) in farm-recovered isolates. This study aimed to characterize the virulence, AMR, and biofilm formation of S. hyicus isolates from Spanish swine farms. A total of 49 isolates were analyzed, originating from animals with cutaneous, reproductive, and systemic clinical signs. Half of the isolates (49.0%) were positive for at least one virulence factor (VF) gene, with SHETA being the most frequent (28.6%). A high frequency of multidrug resistant (MDR) isolates was observed (83.7%), with significant resistance to commonly used antimicrobials, including lincosamides (83.7%), pleuromutilins (81.6%), penicillins (75.5%), and tetracyclines (73.5%). All isolates exhibited robust in vitro biofilm formation capacity (DC = 15.6 ± 7.0). Significant associations were found between VFs, biofilm formation, and AMR patterns, highlighting the link between the resistance to lincosamides and pleuromutilins (p p ExhC and ExhD VF genes. These findings underscore the need for targeted diagnostics to improve management and therapeutic strategies to mitigate the impact of S. hyicus on swine production.

Keywords

• antimicrobial resistance
• biofilm formation
• exfoliative toxins
• exudative epidermitis
• <i>Staphylococcus hyicus</i>
• virulence