Research Centre for Agriculture and Environment (CREA-AA), Council for Agricultural Research and Agricultural Economics Analysis, Bologna, Italy; Department of Veterinary Sciences, University of Bologna, Ozzano Dell'Emilia (BO), Italy; Department of Veterinary Sciences, University of Pisa, Pisa, Italy.
Research Centre for Agriculture and Environment (CREA-AA), Council for Agricultural Research and Agricultural Economics Analysis, Bologna, Italy; DISTAL-Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy.
Chemosphere. 2024 Aug;362:142717. doi: 10.1016/j.chemosphere.2024.142717. Epub 2024 Jun 27.
Colistin is a polymyxin antimicrobic mainly used to treat infection caused by multi-drug resistant Gram-negative bacteria. Mechanisms of colistin resistance are linked to the mobile colistin resistance (mcr) genes, which are transferable within mobile plasmids. Currently, there is limited research on the environmental dissemination of these genes. The behavioural and morphological characteristics of Apis mellifera L. make honey bees effective environmental bioindicators for assessing the prevalence of antimicrobial-resistant bacteria. This study aims to evaluate the colistin phenotypic and genotypic resistance in environmental Gram-negative bacteria isolated from foraging honey bees, across a network of 33 colonies distributed across the Emilia-Romagna region in Italy. Phenotypic resistances were determined through a microdilution assay using the minimum inhibitory concentration (MIC) with dilutions ranging from 0.5 μg/ml to 256 μg/ml. Strains with MIC values gather than 2 μg/ml were classified as resistant. Also, the identification of the nine mcr genes was carried out using two separate multiplex PCR assays. The study found that 68.5% of isolates were resistant and the genus with the higher resistance rates observed in Enterobacter spp. (84.5%). At least one mcr gene was found in 137 strains (53.3%). The most detected gene was mcr5 (35.3%), which was the most frequently detected gene in the seven provinces, while the least observed was mcr4 (4.8%), detected only in two provinces. These results suggested the feasibility of detecting specific colistin resistance genes in environmentally spread bacteria and understanding their distribution at the environmental level, despite their restricted clinical use. In a One-Health approach, this capability enables valuable environmental monitoring, considering the significant role of colistin in the context of public health.
黏菌素是一种多黏菌素类抗菌药物，主要用于治疗多重耐药革兰氏阴性菌引起的感染。黏菌素耐药机制与可移动黏菌素耐药（mcr）基因有关，这些基因可在移动质粒中转移。目前，关于这些基因在环境中的传播，研究还很有限。 意大利艾米利亚-罗马涅大区的 33 个蜂群网络中，研究人员从觅食的蜜蜂身上分离出环境革兰氏阴性菌，研究了这些蜜蜂的行为和形态特征，发现它们是评估抗微生物药物耐药细菌流行情况的有效环境生物标志物。本研究旨在评估意大利艾米利亚-罗马涅大区的 33 个蜂群网络中，从觅食的蜜蜂身上分离出的环境革兰氏阴性菌中黏菌素的表型和基因型耐药情况。通过使用最小抑菌浓度（MIC）的微量稀释法测定表型耐药性，MIC 的稀释范围从 0.5μg/ml 到 256μg/ml。MIC 值大于 2μg/ml 的菌株被归类为耐药菌株。同时，使用两个单独的多重 PCR 检测试剂盒对 9 种 mcr 基因进行了鉴定。研究发现，68.5%的分离株具有耐药性，其中肠杆菌属的耐药率最高（84.5%）。在 137 株菌中至少发现了一种 mcr 基因（53.3%）。检测到的最常见基因是 mcr5（35.3%），它在七个省都有检测到，而检测到的最少的基因是 mcr4（4.8%），仅在两个省检测到。这些结果表明，尽管黏菌素的临床应用受到限制，但在环境中传播的细菌中检测特定的黏菌素耐药基因，并了解其在环境水平上的分布是可行的。在“One-Health”方法中，这种能力使我们能够进行有价值的环境监测，考虑到黏菌素在公共卫生方面的重要作用。
