Ghibaudo Giovanni, Santospirito Davide, Sala Andrea, Flisi Sara, Taddei Simone, Cavirani Sandro, Cabassi Clotilde Silvia
Clinica Veterinaria Malpensa, via G. Marconi 27, 21017, Samarate (VA), Italy.
Dipartimento di Scienze Medico-Veterinarie, University of Parma, via del Taglio 10, 43126, Parma, Italy.
Vet Dermatol. 2016 Oct;27(5):391-e98. doi: 10.1111/vde.12371. Epub 2016 Aug 21.
Pseudomonas aeruginosa (PA) may cause suppurative otitis externa with severe inflammation and ulceration in dogs. Multidrug resistance is commonly reported for this organism, creating a difficult therapeutic challenge.
The aim of this study was to evaluate the in vitro antimicrobial activity of a gel containing 0.5 μg/mL of antimicrobial peptide AMP2041, 0.07% chlorhexidine digluconate (CLX), 0.4% Tris and 0.1% EDTA on 30 clinical isolates of PA from canine otitis externa.
Antimicrobial activity was evaluated through minimal bactericidal concentration (MBC). Standardized bacterial suspensions were incubated with different concentrations of the gel at 37°C for 30 min and plated for colony forming unit (CFU) counts. Time-to-kill kinetics were evaluated with the undiluted product and at MBC for each PA strain at 30 s, 1, 5, 10, 15, 30 min, 24 and 48 h.
The MBC was 1:64 for two of 30 strains, 1:128 for 15 of 30 strains and 1:256 for 13 of 30 strains. The geometric mean was 1:165, equivalent to a concentration of 0.003 μg/mL AMP2041 + 0.0004% CLX + 0.0024%Tris + 0.0006% EDTA. Time-to-kill assays with the undiluted product showed complete bactericidal effect within 30 s for all isolates, whereas at the MBC this effect was reached within 5 min for 20 of 30 isolates and within 30 min for all isolates. Bactericidal activity was maintained after 48 h for all isolates.
This gel has shown rapid, complete and long-lasting activity against a panel of 30 PA isolates from cases of canine otitis externa.
铜绿假单胞菌（PA）可导致犬化脓性外耳炎，并伴有严重炎症和溃疡。该菌普遍存在多重耐药性，给治疗带来了难题。
本研究旨在评估一种凝胶的体外抗菌活性，该凝胶含有0.5μg/mL抗菌肽AMP2041、0.07%葡萄糖酸氯己定（CLX）、0.4%三羟甲基氨基甲烷（Tris）和0.1%乙二胺四乙酸（EDTA），用于检测来自犬外耳炎的30株临床分离PA菌株。
通过最低杀菌浓度（MBC）评估抗菌活性。将标准化细菌悬液与不同浓度的凝胶在37℃孵育30分钟，然后接种以进行菌落形成单位（CFU）计数。用未稀释产品和每种PA菌株在MBC浓度下，于30秒、1、5、10、15、30分钟、24和48小时评估杀菌动力学。
30株菌株中有2株的MBC为1:64，15株为1:128，13株为1:256。几何平均值为1:165，相当于0.003μg/mL AMP2041 + 0.0004% CLX + 0.0024% Tris + 0.0006% EDTA的浓度。用未稀释产品进行的杀菌试验表明，所有分离株在30秒内均有完全杀菌效果，而在MBC浓度下，30株分离株中有20株在5分钟内达到此效果，所有分离株在30分钟内达到此效果。所有分离株在48小时后仍保持杀菌活性。
该凝胶对来自犬外耳炎病例的30株PA分离株显示出快速、完全且持久的活性。
