Blondeau Joseph M, Shebelski Shantelle D
Division of Clinical Microbiology, Royal University Hospital and Saskatoon Health Region, 103 Hospital Drive, Saskatoon, Saskatchewan, S7N 0W8, Canada.
Departments of Microbiology and Immunology, Pathology and Ophthalmology, University of Saskatchewan, 103 Hospital Drive, Saskatoon, Saskatchewan, S7N 0W8, Canada.
Vet Dermatol. 2016 Aug;27(4):267-e63. doi: 10.1111/vde.12334. Epub 2016 Jun 15.
Bacterial eradication is necessary for clinical cure of infections and antimicrobial agents are important adjunctive therapies for inhibiting the growth of or killing bacteria. Pre-existing skin diseases predispose animals to infection by Staphylococcus pseudintermedius and, more rarely, by Gram-negative bacilli. The property of rapid killing of bacteria may influence drug selection and duration of therapy in the setting of infection.
To test the killing of canine isolates of S. pseudintermedius and Escherichia coli by cefazolin, cefovecin, doxycycline and pradofloxacin at the minimum inhibitory, mutant prevention, maximum serum and maximum tissue drug concentrations.
Under standard conditions, bacterial cells were exposed to clinically relevant drug concentrations in vitro and the log10 reduction (and % kill) of viable cells measured at 5, 10, 15, 20, 25, 30, 60, 120 and 180 min after drug exposure.
Statistically significant differences were seen between killing efficiencies by pradofloxacin versus the other agents, whereby pradofloxacin killed cells more rapidly than the others. For example, against the S. pseudintermedius strains, significantly more cells were killed by pradofloxacin following 15 min of maximum tissue drug concentration exposure than for cefazolin (P = 0.0002), cefovecin (P = 0.0007) and doxycycline (P ≤ 0.0001).
The rank order of potency based on these kill experiments was pradofloxacin > cefazolin > cefovecin > doxycycline. Rapid killing of bacteria affects the speed of clinical resolution and may influence drug selection and duration of therapy for skin infections.
细菌清除对于感染的临床治愈是必要的，抗菌药物是抑制细菌生长或杀灭细菌的重要辅助治疗手段。皮肤疾病会使动物更容易感染中间型葡萄球菌，较少情况下也会感染革兰氏阴性杆菌。快速杀灭细菌的特性可能会影响感染情况下的药物选择和治疗持续时间。
在最低抑菌浓度、突变预防浓度、最高血清浓度和最高组织药物浓度下，测试头孢唑林、头孢维星、强力霉素和普拉氟沙星对犬源中间型葡萄球菌和大肠杆菌分离株的杀菌效果。
在标准条件下，将细菌细胞在体外暴露于临床相关药物浓度，并在药物暴露后5、10、15、20、25、30、60、120和180分钟测量活菌的log10减少量（及杀灭百分比）。
普拉氟沙星与其他药物的杀菌效率存在统计学显著差异，普拉氟沙星比其他药物能更快速地杀灭细胞。例如，对于中间型葡萄球菌菌株，在最高组织药物浓度暴露15分钟后，普拉氟沙星杀灭的细胞比头孢唑林（P = 0.0002）、头孢维星（P = 0.0007）和强力霉素（P≤0.0001）显著更多。
基于这些杀菌实验的效力排序为普拉氟沙星>头孢唑林>头孢维星>强力霉素。细菌的快速杀灭会影响临床症状消退的速度，并可能影响皮肤感染的药物选择和治疗持续时间。
