The spread of antibiotic resistance bacteria and their resistance genes (ARGs) represents a great concern to public health worldwide. The aquatic ecosystems are considered as hot spot for horizontal gene transfer, and sediments act as a reservoir of different contaminants. However, the occurrence of agricultural versus medical ARGs in Swiss freshwater reservoirs is understudied. Consequently, in this study, we aimed to quantitate broad-spectrum β-lactam and sulfonamide resistance genes (bla_TEM, bla_SHV, bla_CTX-M, bla_NDM, sul1, and sul2) and the total bacterial load (16S rRNA genes) from the total DNA extracted from the surface sediments of the Lake Brêt, Switzerland using quantitative polymerase chain reaction. In addition, sediment physicochemical parameters including organic matter, grain size, and toxic metal were analyzed. The results highlight the widespread dissemination of bla_TEM, bla_SHV, and sul1, which were also highly correlated to bacterial biomass and organic matter content (R > 0.75, p < 0.05). The bla_CTX-M and sul2 were occasionally present and positively correlate with the concentrations of Cr, Mn, Fe, and Ni, linking it to agricultural practices. These findings demonstrate a fixation of last ARGs’ generation in the environment, whereas actual antibiotic regulation tends to limit the dissemination of other ARGs in the studied lake reservoir.

中文翻译：

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瑞士布莱特湖淡水水库中β-内酰胺和磺胺抗性基因的流行

抗生素抗性细菌及其抗性基因（ARG）的传播代表着全球公共卫生的高度关注。水生生态系统被认为是水平基因转移的热点，而沉积物则充当了各种污染物的储存库。但是，对瑞士淡水水库中农业和医学ARGs的发生还没有进行研究。因此，在这项研究中，我们旨在量化广谱β-内酰胺和磺酰胺耐药基因（bla _TEM，bla _SHV，bla _CTX-M，bla _NDM，sul1和sul2）和使用定量聚合酶链反应从瑞士布雷特湖表层沉积物中提取的总DNA提取的总细菌载量（16S rRNA基因）。此外，还分析了沉积物的理化参数，包括有机物，晶粒度和有毒金属。结果突出了bla _TEM，bla _SHV和sul1的广泛传播，它们也与细菌生物量和有机质含量高度相关（R  > 0.75，p  <0.05）。该BLA _CTX-M和sul2偶尔存在且与Cr，Mn，Fe和Ni的浓度呈正相关，并将其与农业实践联系起来。这些发现证明了环境中最后一个ARGs的产生是固定的，而实际的抗生素调节往往会限制其他ARGs在所研究的湖泊水库中的传播。