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

Abstract

Infections by Staphyloccocus pseudintermedius in the skin of dogs have been object of studies, since such microorganisms often present multiple resistance to antibiotics. This study aimed to identify and evaluate the antimicrobial susceptibility of Staphylococcus pseudintermedius (SP) strains isolated from dogs with otitis. Swabs from both ears of 52 dogs with otitis (n=104) were included. Bacteria were cultured using Muller-Hinton agar (supplemented with 5% equine blood and incubated at 37°C for 24 to 48 hours. All colonies underwent biochemical evaluation for identification of staphylococci. The identity of colonies as SP was confirmed by polymerase chain reaction. The antimicrobial susceptibility of SP strains was evaluated by disk diffusion. The presence of the gene mecA was evaluated in all SP isolates by PCR. Forty-four SP strains were isolated from swabs of 31 dogs (31/52, 59.6%). Seventy-five percent of the strains were susceptible to cephalexin and 93.2% to amoxicillin plus clavulanic acid. Less than 23% of the strains were susceptible to penicillin. For non-beta-lactam antimicrobials, 63.6% of the strains showed resistance to sulfamethoxazole-trimethoprim, 61.4% to tetracycline, and 38, 64% to enrofloxacin. Aminoglycoside resistance rate was 27.3% for gentamicin. Resistance to oxacillin in vitro was detected in 13 of the 44 strains (29, 55%). A total of 12 strains (27.3%) were positive for mecA gene and five of these 12 strains were susceptible to in vitro oxacillin. Twenty-six (59, 1%) strains were resistant to three or more classes of antimicrobials, and classified as multi resistant. Our results showed high frequency of SP and multi resistant isolates to antimicrobials commonly used in veterinary.

Changes in the ear canal microbiota of dogs with otitis externa

“…2016; Scherer et al . 2018). Pseudomonas aeruginosa , Escherichia coli , Streptococcus sp., Enterococcus sp.…”

Antimicrobial resistance evaluation of bacteria isolated from infections in small animals in the Umuarama region, Paraná

“…Stefanetti et al (2017) detected resistance to fluoroquinolones in 76% of isolates to enrofloxacin; Silva et al (2014) by 20.1% for enrofloxacin and 18.8% for ciprofloxacin, representing 22.3% of fluoroquinolone-resistant bacterial isolates; Ishii et al (2011) found resistance to enrofloxacin in 53.8% of isolates and norfloxacin in 41.3%. Scherer et al (2018) detected 38.6% of resistance to enrofloxacin; Kohl et al (2016) detected 30% of resistance to enrofloxacin in Gram-negative bacteria and 13.33% in Gram-positive bacteria; and Carvalho et al (2016), 11.9% to ciprofloxacin.…”

“…Unlike Stefanetti et al (2017) in Italy, with resistance in 43% of S. pseudintermedius isolates for amikacin and 61% for gentamicin. Scherer et al (2018) studying S. pseudintermedius in dogs with otitis external in Minas Gerais, Brazil, found 27.3% of resistance to gentamicin. Kohl et al (2016) in the state of Santa Catarina, Brazil, detected gentamicin resistance in 33.33% of Gram-negative and 12% of Gram-positive.…”

Minimum inhibitory concentration of essential oils against Staphylococcus aureus isolated from dogs with external otitis

“…However, resistance to conventional drugs and the emergence of multidrug-resistant isolates (MDR) has increased in recent years (Blair, Webber, Baylay, Ogbolu, & Piddock, 2014;Scherer et al, 2018). Therefore, the search for alternative treatments is necessary to fight against resistant microorganisms associated with bacterial diseases.…”