Schick Anthea E, Angus John C, Coyner Kimberly S
Dermatology Clinic for Animals, Gilbert, Arizona, USA.
Vet Dermatol. 2007 Apr;18(2):120-6. doi: 10.1111/j.1365-3164.2007.00581.x.
The purpose of this study was to evaluate interlaboratory variation in isolation and antibiotic susceptibility pattern of Pseudomonas spp. as reported to veterinarians for cases of canine chronic bacterial otitis externa. Twenty-six dogs with unilateral or bilateral bacterial otitis externa from multiple referral practices were included in this prospective study. Triplicate samples collected simultaneously from the same location in the external ear canal were randomly submitted to three laboratories for culture and susceptibility testing. Pseudomonas spp. were isolated from 18 of 34 (53%) ears. All three laboratories agreed on the presence of Pseudomonas spp. in 15 (83.3%) ears sampled. However, two laboratories agreed on two (11.1%) occasions, and on one occasion (5.5%) Pseudomonas spp. were identified in only one laboratory. Minimum inhibitory concentration (MIC) susceptibilities to 11 antibiotics were compared between laboratories B and C. Using laboratory-defined susceptibility of sensitive (S), intermediate (I) and resistant (R), none of the 16 Pseudomonas spp. with MIC data reported had identical patterns of antibiotic susceptibility. Agreement in susceptibility to individual antibiotics was observed in 13 of 16 (81%) occasions for amikacin and gentamicin, 10 of 16 (63%) occasions for ticarcillin, and nine of 16 (56%) for enrofloxacin. These results indicate that Pseudomonas spp. were identified by all three laboratories chosen for this study in 83% of the time. Moreover, antibiotic susceptibility patterns and MIC values reported to veterinarians may not agree between laboratories. Veterinarians should interpret bacterial culture and susceptibility results with multiple caveats including variability between laboratories.
本研究的目的是评估向兽医报告的犬慢性细菌性外耳炎病例中假单胞菌属的实验室间分离差异和抗生素敏感性模式。本前瞻性研究纳入了来自多个转诊机构的26只患有单侧或双侧细菌性外耳炎的犬。从外耳道同一位置同时采集的三份重复样本被随机送交三个实验室进行培养和药敏试验。在34只耳朵中的18只（53%）分离出了假单胞菌属。在采样的15只耳朵（83.3%）中，所有三个实验室都一致认为存在假单胞菌属。然而，有两次（11.1%）两个实验室意见一致，有一次（5.5%）只有一个实验室鉴定出假单胞菌属。比较了实验室B和C对11种抗生素的最低抑菌浓度（MIC）敏感性。根据实验室定义的敏感（S）、中介（I）和耐药（R）敏感性标准，报告有MIC数据的16株假单胞菌属中，没有一株具有相同的抗生素敏感性模式。对于阿米卡星和庆大霉素，16次中有13次（81%）观察到对个别抗生素敏感性的一致性；对于替卡西林，16次中有10次（63%）；对于恩诺沙星，16次中有9次（56%）。这些结果表明，本研究选择的所有三个实验室在83%的时间里都鉴定出了假单胞菌属。此外，各实验室向兽医报告的抗生素敏感性模式和MIC值可能不一致。兽医在解释细菌培养和药敏结果时应考虑多种注意事项，包括实验室间的变异性。
