Multidrug resistant Staphylococcus pseudintermedius isolated from superficial bacterial folliculitis in dogs from Portugal and Spain

Abstract

Multidrug resistant Staphylococcus pseudintermedius isolates have been recently increasing, which is alarming and dramatically decreases antimicrobial treatment options. T he objective of this study was to evaluate the incidence of multidrug resistance (MDR) in meticillin-susceptible and resistant Staphylococcus pseudintermedius isolates (MSSP/MRSP), previously collected from dogs with superficial bacterial folliculitis (SBF) in two referral hospitals in Portugal and Spain. Sixty S. pseudintermedius isolates were tested for oxacillin susceptibility by the Kirby-Bauer technique and divided into MRSP (30/60) and MSSP (30/60). Isolates were tested for first and second tier antibiotics recommended by the Working Group of the International Society for Companion Animal Infectious Diseases (ISCAID). All MRSP exhibited resistance to amoxicillin-clavulanic acid, clindamycin and erythromycin. High resistance levels were observed to trimethoprimsulfamethoxazole (97%), tetracycline and gentamicin (87%), cefalothin and enrofloxacin (83%), pradofloxacin (80%) and minocycline (50%). Low resistance level was observed for chloramphenicol (17%), amikacin (7%) and rifampicin (7%). One MRSP was susceptible to trimethoprim-sulfamethoxazole. Sixty and 57% of MSSP were resistant to tetracycline and minocycline, respectively. Additionally, 43% of the isolates were resistant to clindamycin and erythromycin, 20% to trimethoprim-sulfamethoxazole, 7% to enrofloxacin and pradofloxacin and 3% to chloramphenicol, gentamicin and amikacin. None were resistant to amoxicillin-clavulanic acid, cefalothin and rifampicin. Most isolates were MDR (38/60). All non-MDR isolates were MSSP. Meticillin resistance was associated with MDR to other classes of antibiotics (P=0.001). Our study showed correlation between MRSP and MDR. The presence of MRSP should alert the practitioner for MDR and limited antibiotic options.