Participation and Drug Resistance of Coagulase-Positive Staphylococci Isolated From Cases of Pyoderma and Otitis Externa in Dogs

Abstract

Staphylococcus pseudintermedius is considered as a major pathogen in dogs, typically involved in skin and ear infections. Other staphylococci, as well as ß-hemolytic streptococci, Pseudomonas aeruginosa or yeast-like fungi of the genus Malassezia also play an important role in inflammation. Because of this diversity, an appropriate choice of antimicrobial agent(-s) can be difficult. A total of 474 tests were performed (including 255 pyoderma and 219 otitis externa cases). In the case of pyoderma, 82.4% of skin lesions were caused by stap hylococci. Co-infections with ß-hemolytic streptococci (17.3 %), Malassezia sp. (15.7 %) and P. aeruginosa (4.3 %) were also recorded. For external ear infections, the share of staphylococci in inflammation was lower (44.8 %) than that of Malassezia sp. (58 %). Relatively frequent co-infections with ß-hemolytic streptococci (18.8 %) and P. aeruginosa (7.8 %) were also noted. A total of 308 susceptibility tests for coagulase-positive staphylococci were performed (210 and 98 for skin and otitis externa, respectively). In ≥ 86 % of cases, amoxicillin potentiated with clavulanic acid, cephalexin and fluoroquinolones effectively inhibited the growth of all bacteria in vitro. A total of 25 isolates (24 S. pseudintermedius and one S. aureus) were considered as methicillin-resistant. The mecA gene was identified in 100 % of those strains but only 44 % of the isolates additionally carried the blaZ gene. All mecA-positive staphylococci were multidrugresistant, mainly to all ß-lactams, fluoroquinolones, linkozamides, macrolides as well as sulfonamides but always susceptible to mupirocin. Overall, multidrug-resistance varied between 6 % (otitis externa) and 9 % (inflamed skin) and may become a significant problem in the future.

Activity of Patchouli and Tea Tree Essential Oils against Staphylococci Isolated from Pyoderma in Dogs and Their Synergistic Potential with Gentamicin and Enrofloxacin

“…coagulans ), Gram-negative bacilli—such as Pseudomonas aeruginosa , Proteus spp., and Escherichia coli —or yeast-like fungi ( Malassezia sp., Candida sp.) [ 5 ]. These microorganisms are the natural commensal microflora of the skin in dogs; nevertheless, when they are abundant and the animal’s immune system declines, they can be the cause of skin lesions.…”