Laboratorio de Patobiología Acuática, Instituto del Mar del Perú (IMARPE), Callao, Peru.
Universidad Andrés Bello, Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Facultad de Ciencias de la Vida, Viña del Mar, Chile.
Dis Aquat Organ. 2024 Aug 29;159:127-131. doi: 10.3354/dao03810.
Yersiniosis, caused by Yersinia ruckeri, has become the most common disease in farmed rainbow trout Oncorhynchus mykiss in Peru, affecting Puno and Junín Regions, important aquaculture areas in the country. Florfenicol (FLO) and oxytetracycline (OXY) are the antimicrobials most frequently used to mitigate losses attributed to this pathogen. This study presents an analysis of the susceptibility patterns of 60 Y. ruckeri isolates (30 isolates each from Puno and Junín), including the type strain CECT 4319T and the strains CECT 955 and CECT 956, against FLO and OXY. Minimum inhibitory concentrations (MICs) were determined following the guideline for standard broth dilution method published by the Clinical and Laboratory Standards Institute. MIC results ranged from 4.0 to 8.0 µg ml-1 for FLO and 0.5 to 4.0 µg ml-1 for OXY. Normalized resistance interpretation (NRI) analysis identified epidemiological cut-off values of ≤16.0 µg ml-1 for FLO and ≤4.0 µg ml-1 for OXY. All Peruvian isolates, including the collection strains, were categorized as wild-type for both antimicrobials. Even though the number of Y. ruckeri isolates with MIC values of 8 µg ml-1 for FLO is more than double in Puno than in Junín (15 vs. 7 isolates), the NRI analysis showed the same epidemiological cutoff of 16 µg ml-1; while for OXY, it was 4.0 µg ml-1 for Puno and 2.0 µg ml-1 for Junín. This study establishes the basis for monitoring susceptibility to FLO and OXY in new Y. ruckeri isolates in Peruvian rainbow trout farming.
鱼类弧菌病由鲁氏耶尔森菌引起，已成为秘鲁养殖虹鳟鱼（Oncorhynchus mykiss）最常见的疾病，影响该国的重要水产养殖区普诺省和胡宁省。氟苯尼考（FLO）和土霉素（OXY）是用于减轻该病原体引起的损失的最常用的抗菌药物。本研究分析了 60 株鲁氏耶尔森菌分离株（来自普诺和胡宁的 30 株分离株）的药敏模式，包括参考株 CECT 4319T 以及 CECT 955 和 CECT 956 株，针对 FLO 和 OXY。采用临床和实验室标准协会发布的标准肉汤稀释法指南测定最小抑菌浓度（MIC）。FLO 的 MIC 结果范围为 4.0 至 8.0 µg ml-1，OXY 的 MIC 结果范围为 0.5 至 4.0 µg ml-1。归一化耐药性解释（NRI）分析确定了 FLO 的 ≤16.0 µg ml-1和 OXY 的 ≤4.0 µg ml-1的流行病学截断值。所有秘鲁分离株，包括收集的菌株，对这两种抗生素均为野生型。尽管 FLO 的 MIC 值为 8 µg ml-1的鲁氏耶尔森菌分离株在普诺的数量是胡宁的两倍多（15 株比 7 株），但 NRI 分析显示相同的流行病学截断值为 16 µg ml-1；而对于 OXY，普诺为 4.0 µg ml-1，胡宁为 2.0 µg ml-1。本研究为监测秘鲁养殖虹鳟鱼中新的鲁氏耶尔森菌分离株对 FLO 和 OXY 的敏感性奠定了基础。
