Plowgian Curtis, Blondeau Joseph M, Levinson Matthew, Rosenkrantz Wayne
Animal Dermatology Clinic, 3901 E 82nd St, Indianapolis, IN, 46250, USA.
Division of Clinical Microbiology, Royal University Hospital and Saskatchewan Health Authority, 103 Hospital Drive, Saskatoon, Saskatchewan, Canada, S7N 0W8.
Vet Dermatol. 2019 Dec;30(6):481-e142. doi: 10.1111/vde.12781. Epub 2019 Sep 5.
Moxifloxacin is a fourth-generation fluoroquinolone (FQ) that is approved for use in people to treat a variety of infections. Some veterinary microbiology laboratories report moxifloxacin in culture and sensitivity profiles for Staphylococcus pseudintermedius and S. schleiferi albeit using Clinical & Laboratory Standards Institute (CLSI) breakpoints for S. aureus. Previous studies have shown that S. aureus breakpoints can mischaracterize S. pseudintermedius susceptibility to various drugs. Pradofloxacin is a third generation veterinary FQ with a similar mechanism of action and spectrum of activity to moxifloxacin; however, the dose format (25 mg/mL solution) available in the USA may limit its practical use in large dogs.
To determine the minimum inhibitory concentration (MIC), mutant prevention concentration (MPC) and mutant selection window (MSW) of moxifloxacin and pradofloxacin for isolates of S. pseudintermedius and S. schleiferi.
Pulsed-field gel electrophoresis was performed to establish that each bacterial isolate selected for testing represented an unique strain. The MIC, MPC and MSW for moxifloxacin and pradofloxacin were determined from 60 strains of S. pseudintermedius and seven strains of S. schleiferi.
The MIC and MPC ranges of moxifloxacin and pradofloxacin for meticillin-susceptible S. pseudintermedius were similar. However, MIC and MPC ranges were much wider and resistance to both drugs was more common for meticillin-resistant strains of S. pseudintermedius and S. schleiferi.
The narrow MSW of these drugs may reduce the risk of selecting for antibiotic-resistant subpopulations. Pharmacokinetic, pharmacodynamic and safety studies are needed.
莫西沙星是一种第四代氟喹诺酮类药物（FQ），已被批准用于人类治疗多种感染。一些兽医微生物实验室在中间型葡萄球菌和施氏葡萄球菌的培养及药敏试验结果中报告了莫西沙星，尽管使用的是针对金黄色葡萄球菌的临床和实验室标准协会（CLSI）的断点值。先前的研究表明，金黄色葡萄球菌的断点值可能会错误地描述中间型葡萄球菌对各种药物的敏感性。普拉德氟沙星是第三代兽用FQ，其作用机制和活性谱与莫西沙星相似；然而，美国现有的剂型（25mg/mL溶液）可能会限制其在大型犬中的实际应用。
确定莫西沙星和普拉德氟沙星对中间型葡萄球菌和施氏葡萄球菌分离株的最低抑菌浓度（MIC）、突变预防浓度（MPC）和突变选择窗（MSW）。
进行脉冲场凝胶电泳以确定所选用于测试的每个细菌分离株代表一个独特的菌株。从60株中间型葡萄球菌和7株施氏葡萄球菌中测定了莫西沙星和普拉德氟沙星的MIC、MPC和MSW。
莫西沙星和普拉德氟沙星对甲氧西林敏感的中间型葡萄球菌的MIC和MPC范围相似。然而，对于甲氧西林耐药的中间型葡萄球菌和施氏葡萄球菌菌株，MIC和MPC范围要宽得多，并且对这两种药物的耐药性更为常见。
这些药物狭窄的MSW可能会降低选择抗生素耐药亚群的风险。需要进行药代动力学、药效学和安全性研究。
