Ullmann Ingvild F, Tunsjø Hege S, Andreassen Monica, Nielsen Kaare Magne, Lund Vidar, Charnock Colin
Department of Life Sciences and Health, OsloMet - Oslo Metropolitan University, Oslo, Norway.
Department of Zoonotic, Food- and Waterborne Infections, Norwegian Institute of Public Health, Oslo, Norway.
Front Microbiol. 2019 Mar 13;10:487. doi: 10.3389/fmicb.2019.00487. eCollection 2019.
Through a culture-based approach using sludge from drinking water treatment plants, this study reports on the presence of aminoglycoside resistant bacteria at 23 different geographical locations in Norway. Sludge samples are derived from a large environmental area including drinking water sources and their surrounding catchment areas. Aminoglycoside resistant bacteria were detected at 18 of the sample sites. Only five samples did not show any growth of isolates resistant to the selected aminoglycosides, kanamycin and gentamycin. There was a statistically significant correlation between the numbers of kanamycin and gentamycin resistant bacteria isolated from the 23 samples, perhaps suggesting common determinants of resistance. Based on 16S rRNA sequencing of 223 aminoglycoside resistant isolates, three different genera of were found to dominate across samples. These were and Further phenotypic and genotypic analyses showed that efflux pumps, reduced membrane permeability and four assayed genes coding for aminoglycoside modifying enzymes AAC(6')-Ib, AAC(3')-II, APH(3')-II, APH(3')-III, could only explain the resistance of a few of the isolates selected for testing. ' was detected in 1.6% of total isolates, ' and ' in 0.8%, while ' was not detected in any of the isolates. The isolates, for which potential resistance mechanisms were found, represented 13 different genera suggesting that aminoglycoside resistance is widespread in bacterial genera indigenous to sludge. The present study suggests that aminoglycoside resistant bacteria are present in Norwegian environments with limited anthropogenic exposures. However, the resistance mechanisms remain largely unknown, and further analyses, including culture-independent methods, could be performed to investigate other potential resistance mechanisms. This is, to our knowledge, the first large scale nationwide investigation of aminoglycoside resistance in the Norwegian environment.
通过基于培养的方法，利用来自饮用水处理厂的污泥，本研究报告了挪威23个不同地理位置存在氨基糖苷类耐药菌的情况。污泥样本取自包括饮用水源及其周边集水区在内的大片环境区域。在18个采样点检测到了氨基糖苷类耐药菌。只有5个样本未显示出对所选氨基糖苷类药物（卡那霉素和庆大霉素）耐药的分离株生长。从23个样本中分离出的卡那霉素和庆大霉素耐药菌数量之间存在统计学上的显著相关性，这可能表明存在共同的耐药决定因素。基于对223株氨基糖苷类耐药分离株的16S rRNA测序，发现有三个不同的属在各样本中占主导地位。它们分别是 、 和 。进一步的表型和基因型分析表明，外排泵、降低的膜通透性以及四个编码氨基糖苷类修饰酶AAC(6')-Ib、AAC(3')-II、APH(3')-II、APH(3')-III的检测基因，只能解释少数所选测试分离株的耐药性。在总共1.6%的分离株中检测到了 ，在0.8%的分离株中检测到了 和 ，而在任何分离株中均未检测到 。发现有潜在耐药机制的分离株代表了13个不同的属，这表明氨基糖苷类耐药性在污泥原生细菌属中广泛存在。本研究表明，在人为暴露有限的挪威环境中存在氨基糖苷类耐药菌。然而，耐药机制在很大程度上仍然未知，可以进行进一步分析，包括非培养方法，以研究其他潜在的耐药机制。据我们所知，这是挪威环境中氨基糖苷类耐药性的首次大规模全国性调查。
