Private Practitioner, Centro Veterinario Cattolica, Cattolica, Italy.
Department of Veterinary Medicine, University of Perugia, Perugia, Italy.
Vet Dermatol. 2023 Dec;34(6):586-596. doi: 10.1111/vde.13197. Epub 2023 Aug 14.
In canine otitis externa (OE), biofilm-producing bacteria are frequently present but biofilm may be underdiagnosed clinically.
HYPOTHESIS/OBJECTIVES: The study aimed to investigate an association between clinical and cytological findings with bacteriological data from dogs with OE, to establish, through Environmental Scanning Electron Microscope (ESEM) examination, whether the presence of biofilm in vivo can be predicted and to evaluate the impact of biofilm on antimicrobial susceptibility tests.
Fifty-six dogs showing clinical signs of OE were enrolled. One cotton swab each was collected for ESEM, bacterial culture and susceptibility testing and for cytology. Staphylococcus pseudintermedius (n = 42, 48.8%) and Pseudomonas aeruginosa (n = 26, 30.2%) were tested for their ability to form biofilm. Minimum Inhibitory Concentrations (MIC), Minimal Biofilm Inhibitory Concentrations (MBIC) and Minimal Biofilm Eradication Concentrations (MBEC) towards enrofloxacin, gentamicin, polymyxin B and rifampicin were determined.
Pseudomonas aeruginosa was positively associated with the biofilm clinical evaluation (p < 0.01) and neutrophils (p < 0.05), nuclear streaks (p < 0.01) and rods bacteria (p < 0.01) on cytology. S. pseudintermedius was associated with a low presence of neutrophils. There was a statistical correlation between clinical and cytological biofilm presence (p ≤ 0.01), but none with the biofilm production assay nor ESEM biofilm detection. No differences were found comparing the results of MIC and MBIC. MBEC results showed higher values than MIC and MBIC for all antimicrobials tested (p ≤ 0.001).
Biofilm presence in OE was often underdiagnosed. Even if there is no specific clinical or cytological pattern related to biofilm, its presence should always be suspected.
在犬外耳炎（OE）中，经常存在产生生物膜的细菌，但生物膜可能在临床上被漏诊。
假说/目的：本研究旨在调查 OE 犬的临床和细胞学发现与细菌学数据之间的关联，通过环境扫描电子显微镜（ESEM）检查确定体内生物膜的存在是否可以预测，并评估生物膜对抗菌药物敏感性测试的影响。
纳入 56 只出现 OE 临床症状的犬。每个犬分别用一个棉签进行 ESEM、细菌培养和药敏试验以及细胞学检查。测试金黄色葡萄球菌（n=42，48.8%）和铜绿假单胞菌（n=26，30.2%）形成生物膜的能力。确定恩诺沙星、庆大霉素、多粘菌素 B 和利福平的最小抑菌浓度（MIC）、最小生物膜抑菌浓度（MBIC）和最小生物膜清除浓度（MBEC）。
铜绿假单胞菌与生物膜临床评估（p<0.01）和细胞学上的中性粒细胞（p<0.05）、核条纹（p<0.01）和杆菌（p<0.01）呈正相关。金黄色葡萄球菌与中性粒细胞的低存在有关。临床和细胞学生物膜存在之间存在统计学相关性（p≤0.01），但与生物膜产生测定或 ESEM 生物膜检测均无相关性。比较 MIC 和 MBIC 结果时，未发现差异。对于所有测试的抗菌药物，MBEC 结果均高于 MIC 和 MBIC（p≤0.001）。
OE 中生物膜的存在经常被漏诊。即使没有与生物膜相关的特定临床或细胞学模式，也应始终怀疑其存在。
