Emergence and Prevalence Decline of a Phenotypically Multidrug-Resistant Staphylococcus pseudintermedius in Israel

Abstract

The prevalence of multi-drug resistant S. pseudintermedius in Israel (IMDR), as assessed by a standardized disc-diffusion method, increased between 2004 and 2012 and decreased subsequently. Isolates were considered as IMDR if they were resistant to penicillin, oxacillin, ampicillin, amoxicillin–clavulanate, cephalothin, clindamycin, enrofloxacin, sulfamethoxazole-trimethoprim, gentamicin, erythromycin and tetracycline, or susceptible to one–tetracycline or sulfamethoxazole-trimethoprim. Isolates resistant to oxacillin were considered resistant to all beta-lactam antibiotics. The susceptibility to chloramphenicol and florfenicol was tested for 61 IMDR isolates of S. pseudintermedius to evaluate if phenicols may be considered as treatment options. Among them, 43 isolates were resistant to chloramphenicol. Inhibition zones for florfenicol (for which no interpretation standards for canine or feline isolates exist) were between 22 and 28 mm and between 18 and 21 mm for 59 and 2 isolates, respectively. IMDR still represents a challenge for veterinary medicine in Israel requiring further improvement of the standard hygienic procedures in veterinary settings as well as the search for alternative antimicrobial treatments. Puppies imported from Thailand may be a potential source of IMDR strains.