Antimicrobial susceptibility of staphylococci isolated from otitis externa in dogs

Abstract

Z A . 2000. Samples were obtained from 65 unmedicated adult dogs, processed for isolation of Staphylococcus species and tested for susceptibility to penicillin G, gentamicin, oxacillin, tetracycline, trimethoprimsulphamethoxazole, streptomycin, ampicillin and rifampin. Forty-four isolates were obtained, which represents 67Á7% of samples. Coagulase-negative species were most commonly found, and the most frequently isolated staphylococcus species were Staph. epidermidis and Staph. aureus. Other species, such as Staph. simulans, Staph. haemolyticus, Staph. saprophyticus and Staph. intermedius were also isolated. Resistance to antibiotics was frequently observed, with 90Á9% of the isolates showing resistance to at least one drug. The most active antimicrobial agents against staphylococci isolated from otitis externa of dogs were rifampin and oxacillin. Multidrug resistance was a common ®nding, and one strain of Staph. haemolyticus species, was resistant to all tested antimicrobial agents. Resistance to three or more different drugs was a common ®nding, observed in 16 strains (36Á4%) of both coagulase-positive and coagulase-negative staphylococci. This study highlights the emergence of cases of otitis externa determined by coagulase-negative staphylococcus strains and once more emphasizes the need for bacterial culture with species identi®cation and susceptibility testing of swab specimens from the ear canal in order to choose appropriate antimicrobial agents.

Frequency and antimicrobial susceptibility of Staphylococcus pseudintermedius in dogs with otitis externa

“…pseudintermedius was detected in almost 60% of dogs with otitis externa. This rate is higher than that reported in previous studies (LILENBAUM et al, 2000;HOEKSTRA & PAULTON, 2002;PENNA et al, 2010;SAPUTRA et al, 2017). This variation in results might be due to geographical differences, and clinical conditions (with and/or without otitis), age, and breed of the dogs.…”

“…Resistance to sulfamethoxazole-trimethoprim was also reported in other studies (LILENBAUM et al, 2000;DE MARTINO et al, 2016). However, a survey in Europe revealed that sensitivity to sulfonamides was very high (>90.0%).…”

“…In Brazil, studies examining otitis caused by S. pseudintermedius in dogs are scarce, making any comparison difficult. The isolation rate obtained in this study was greater than that reported by the two previously published studies in Brazil (LILENBAUM et al, 2000;PENNA et al, 2010). Taken together, our results indicated that S. pseudintermedius is an important bacterium causing otitis in dogs and should be considered when treating this disease.…”

“…High susceptibility rates to amoxicillin plus clavulanic have been reported previously (PENNA et al, 2010;KROEMER et al, 2014;DE MARTINO et al, 2016). However, resistance to penicillin has not been previously reported ( LILENBAUM et al, 2000, KROEMER et al, 2014;DE MARTINO et al, 2016). Cephalexin is used more commonly to treat pyoderma, a common infection caused by S. pseudintermedius.…”

“…Similar resistance rates were observed for tetracycline in Italy (DE MARTINO et al, 2016). One study in Brazil reported that more than 90% of staphylococci strains were sensitive to tetracycline (LILENBAUM et al, 2000). Reports of enrofloxacin resistance described similar results (PENNA et al, 2010;DE MARTINO et al, 2016), while in Europe the level of susceptibility to fluoroquinolones has been reported as over 90% (KROEMER et al, 2014).…”