Skof Aline, Koller Michael, Baumert Rita, Hautz Jürgen, Treiber Fritz, Kittinger Clemens, Zarfel Gernot
Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria.
Diagnostic and Research Center for Molecular Biomedicine, Medical University of Graz, 8010 Graz, Austria.
Pathogens. 2024 Feb 13;13(2):171. doi: 10.3390/pathogens13020171.
Antibiotic-resistant, facultative pathogenic bacteria are commonly found in surface water; however, the factors influencing the spread and stabilization of antibiotic resistance in this habitat, particularly the role of biofilms, are not fully understood. The extent to which bacterial populations in biofilms or sediments exacerbate the problem for specific antibiotic classes or more broadly remains unanswered. In this study, we investigated the differences between the bacterial populations found in the surface water and sediment/biofilm of the Mur River and the Drava River in Austria. Samples of were collected from both the water and sediment at two locations per river: upstream and downstream of urban areas that included a sewage treatment plant. The isolates were subjected to antimicrobial susceptibility testing against 21 antibiotics belonging to seven distinct classes. Additionally, isolates exhibiting either extended-spectrum beta-lactamase (ESBL) or carbapenemase phenotypes were further analyzed for specific antimicrobial resistance genes. isolates collected from all locations exhibited resistance to at least one of the tested antibiotics; on average, isolates from the Mur and Drava rivers showed 25.85% and 23.66% resistance, respectively. The most prevalent resistance observed was to ampicillin, amoxicillin-clavulanic acid, tetracycline, and nalidixic acid. Surprisingly, there was a similar proportion of resistant bacteria observed in both open water and sediment samples. The difference in resistance levels between the samples collected upstream and downstream of the cities was minimal. Out of all 831 isolates examined, 13 were identified as carrying ESBL genes, with 1 of these isolates also containing the gene for the KPC-2 carbapenemase. There were no significant differences between the biofilm (sediment) and open water samples in the occurrence of antibiotic resistance. For the populations in the examined rivers, the different factors in water and the sediment do not appear to influence the stability of resistance. No significant differences in antimicrobial resistance were observed between the bacterial populations collected from the biofilm (sediment) and open-water samples in either river. The different factors in water and the sediment do not appear to influence the stability of resistance. The minimal differences observed upstream and downstream of the cities could indicate that the river population already exhibits generalized resistance.
耐抗生素的兼性病原菌在地表水中普遍存在；然而，影响该生境中抗生素抗性传播和稳定的因素，尤其是生物膜的作用，尚未完全明确。生物膜或沉积物中的细菌群体在多大程度上加剧了特定抗生素类别或更广泛范围内的问题，仍未得到解答。在本研究中，我们调查了奥地利穆尔河和德拉瓦河地表水与沉积物/生物膜中细菌群体的差异。每条河在两个地点（包括污水处理厂的城市区域的上游和下游）采集水和沉积物样本。分离株针对属于七个不同类别的21种抗生素进行了药敏试验。此外，对表现出超广谱β-内酰胺酶（ESBL）或碳青霉烯酶表型的分离株进一步分析其特定的抗生素抗性基因。从所有地点收集的分离株对至少一种测试抗生素表现出抗性；平均而言，来自穆尔河和德拉瓦河的分离株分别显示出25.85%和23.66%的抗性。观察到的最普遍抗性是对氨苄西林、阿莫西林-克拉维酸、四环素和萘啶酸。令人惊讶地是，在开放水域和沉积物样本中观察到的抗性细菌比例相似。城市上游和下游采集的样本之间的抗性水平差异最小。在所有检测的831株分离株中，有13株被鉴定携带ESBL基因，其中1株还含有KPC-2碳青霉烯酶基因。生物膜（沉积物）和开放水域样本在抗生素抗性的发生方面没有显著差异。对于所检测河流中的细菌群体，水和沉积物中的不同因素似乎不会影响抗性的稳定性。在两条河中，从生物膜（沉积物）和开放水域样本收集的细菌群体之间在抗生素抗性方面没有观察到显著差异。水和沉积物中的不同因素似乎不会影响抗性的稳定性。在城市上游和下游观察到的最小差异可能表明河流中的细菌群体已经表现出普遍抗性。
