Antimicrobial Susceptibilities of Aerobic Isolates from Respiratory Samples of Young New Zealand Horses

Abstract

BackgroundDecreased efficacy of antimicrobials and increased prevalence of multidrug resistance (MDR) is of concern worldwide.ObjectivesTo describe and analyze bacterial culture and antimicrobial susceptibilities from respiratory samples submitted from young horses (4 weeks to 3 years old).AnimalsSamples from 289 horses were submitted to a commercial laboratory.MethodsA retrospective database search of submissions made to a New Zealand veterinary laboratory between April 2004 and July 2014. The results of in vitro susceptibility testing by Kirby‐Bauer disc diffusion were described and tabulated for the major bacterial species isolated. Multiple correspondence analysis (MCA) was used to describe the clustering of MDR isolates and selected demographic variables.ResultsOverall, 774 bacterial isolates were cultured from 237 horses, the majority of these isolates were gram‐positive (67.6%; 95% CI 64.3–70.9%). Streptococcus spp. were the most common genus of bacteria isolated and were 40.1% (95% CI 36.6–43.5%) of the isolates cultured. Susceptibility of Streptococcus spp. to penicillin, gentamicin, and ceftiofur was >85%. Overall, gram‐negative susceptibility to ceftiofur, tetracycline, and TMPS was <75%. MDR was defined as resistance to 3 or more antimicrobials, and was found in 39.2% of horses (93/237; 95% CI 33.0–45.5%).Conclusions and clinical importanceCulture and susceptibility results have highlighted that MDR is an emerging problem for young horses in New Zealand (NZ), where a bacterial respiratory infection is suspected. This should be considered when prescribing antimicrobials, and emphasizes the need for submission of samples for culture and susceptibility.

Safkan İngiliz ve Arap Yarış Atlarında Görülen Beta Hemolitik Streptococcus Türlerinin Sitolojik Bulgular Eşliğinde Çeşitli Vücut Bölgelerinden İzolasyonu ve Antibiyotik Duyarlılıkları

“…Beta hemolytic streptococci species were found to be 100% susceptible against amoxycillin/clavulanic acid, amoxycillin, ampicillin, penicillin, imipenem, ampicillin/ sulbactam and ceftiofur according to the present study in vitro. These results are mostly in agreement with previous studies [1,[3][4][5]19] .…”

“…In New Zealand, multidrug resistance rate of Streptococcus spp. was found to be 3.9% and age of the horse was determined to be significantly associated with multidrug resistance statistically [19] .…”

“…Amikacin (30 µg), amoxicillin/ clavulanic acid (30 µg), amoxicillin (25 µg), ampicillin (10 µg), ceftiofur (30 µg), enrofloxacin (5 µg), gentamicin (10 µg), imipenem (10 µg), kanamycin (30 µg), neomycin (10 µg), oxytetracycline (30 µg), penicillin (10 IU), streptomycin (10 µg), ampicillin sulbactam (20 µg), trimethoprim/ sulfamethoxazole (25 µg) and ceftazidime (30 µg) antimicrobial discs (Oxoid Ltd., Basingstoke, UK) were included in the susceptibility tests. Multidrug antimicrobial resistance was also assessed which was described as an isolate being resistant to three or more of the following antimicrobial agents: enrofloxacin, gentamicin, ceftiofur, penicillin, oxytetracycline and trimethoprim-sulfonamide combination [19] .…”

“…An increased attention has been placed upon antimicrobial resistance in both medical and veterinary field [19] . Streptococcus group C agents isolated from endometrial swabs yielded 82.7% susceptibility to amoxicillin/clavulanic acid, 67.7% ampicillin, 8.4% enrofloxacin, 6.7% gentamicin, 65.2% penicillin, 51.3% rifampicin, 17.0% trimethoprim/ sulfamethoxazole and 15.1% tetracycline in a study performed in Italy [7] .…”

“…Multidrug resistance was defined as resistance to three or more antimicrobial classes in pathogens isolated from animals [19] . In New Zealand, multidrug resistance rate of Streptococcus spp.…”