Antibiotic resistance poses a significant health risk for humans and animals. Wastewater treatment plants (WWTPs) are among the key sources of antibiotic resistance genes (ARGs) in the natural environment. The aim of this study was to analyze the occurrence and seasonal variations of ARGs in treated wastewater flowing to the Pilica River or its tributaries. Samples of treated effluents were collected from 17 WWTPs assigned into three groups based on their population equivalent (PE): <2000, 2000–9999 and 15,000–99,999. Samples were collected four times at two-month intervals between November 2017 and July 2018. The occurrence of the 16S rRNA gene, class 1 integrase (intl1) gene and genes encoding resistance to beta-lactams (bla_TEM, bla_OXA, bla_SHV, bla_CTX-M), tetracyclines (tetA, tetB, tetC, tetD, tetE), fluoroquinolones (aac(6′)-Ib-cr), macrolide, lincosamide and streptogramin (MLS) antibiotics (ermF, linA) and sulfonamides (sul1) was determined by standard PCR. All of the analyzed ARGs, excluding bla_SHV, were detected in treated wastewater. The prevalence of ARGs was more frequently in spring and rarelier in summer. Antibiotic resistance genes were most frequently detected in treated wastewater flows out from small WWTPs (class I, PE <2000).

抗生素抗性对人类和动物构成重大的健康风险。废水处理厂（WWTP）是自然环境中抗生素抗性基因（ARG）的主要来源。这项研究的目的是分析流入Pilica河或其支流的处理废水中ARGs的发生和季节变化。根据17个污水处理厂的污水当量（PE）将其分为三类：<2000、2000–9999和15,000–99,999，收集了经过处理的污水样本。在2017年11月至2018年7月之间，每两个月采集一次四次样品。出现16S rRNA基因，1类整合酶（int l1）基因和编码对β-内酰胺类抗性的基因（bla _TEM，bla _OXA，bla _SHV，bla _CTX-M），四环素类（tet A，tet B，tet C，tet D，tet E），氟喹诺酮类（aac（6'）-Ib-cr），大环内酯类，林可酰胺和链霉菌素（MLS）抗生素（ermF，linA）和磺酰胺类（sul 1）通过标准PCR测定。所有分析的ARG，不包括bla _SHV在处理过的废水中被检测到。ARGs的流行在春季更为频繁，而在夏季则更为罕见。在小型污水处理厂（I类，PE <2000）中，经过处理的废水中最常检测到抗生素抗性基因。