Staphylococcal infections represent a challenge in companion animals and hospitalized patients. This study aimed to assess the resistance of Staphylococcus pseudintermedius isolates, against a broad panel of antibacterials, including exclusive to human medicine. A total of 40 S. pseudintermedius were collected from clinical specimens of dogs (n = 31) and cats (n = 5). All strains were tested for 20 antibacterials, namely 14 Critical Important and eight Highly Important Antibacterials (CIA and HIA, respectively), indicative for 18 antimicrobial classes. All strains were susceptible to seven antibiotics (daptomycin, fosfomycin, fusidic acid, linezolid, quinupristin-dalfopristin, teicoplanin/vancomycin, tigecycline). The highest resistance was against penicillin (97.5% Confidence Interval [CI]: 83.8-100.0), whereas the lowest against telavancin (2.5%, CI: 0.0-16.2). Resistance versus Highest Priority CIA was observed, namely against macrolides (70.0, CI: 52.1-84.3), quinolones (62.5, CI: 44.5-78.3), 5th generation cephalosporins (7.5, CI: 1.3-21.6), and glycopeptides (2.5%, CI: 0.0-14.2). Among High Priority CIA, strains were resistant only to aminoglycosides (65.0, CI: 47.0-80.4) and ansamycins (12.5, CI: 3.8-28.1). We observed the highest resistance against veterinary medicine antibacterials, but there was also resistance against antibacterials exclusive to human medicine, namely ceftaroline (7.5, CI: 1.0-23.8) and telavancin. S. pseudintermedius zoonotic potential and its rate of acquisition of new resistance should encourage surveillance on a broad spectrum of antibacterials.
Keywords: Italy; Staphylococcus pseudintermedius; antimicrobial resistance; antimicrobial susceptibility testing; cat; critically important antimicrobials; dog.