Xia Yubing, Wang Haichen, Li Jun, Wang Haolan, Wang Yuyao, Hu Yongmei, Xia Fengjun, Zou Mingxiang
National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China.
Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China.
Appl Environ Microbiol. 2025 Aug 5:e0002225. doi: 10.1128/aem.00022-25.
The excessive use of silver compounds has led to the environmental dissemination of silver resistance genes. However, little is known about the epidemiology of silver-resistant bacteria in the environment. Wastewater treatment plants (WWTPs) link the clinical settings with the natural environment and serve as a major pathway for silver entering the natural environment. However, their role in the dissemination of silver resistance genes remains unclear. This study investigated the characteristics of silver-resistant bacteria in the vicinity of four WWTPs to assess their environmental impact. Water and sediment samples were collected from the WWTP outfalls and downstream rivers. Among 22 silver-resistant strains obtained through plate screening, the majority were spp., followed by spp. and spp. Notably, ST23 and ST2464 were the predominant sequence types (multilocus sequence typing) identified among the isolates. Antimicrobial susceptibility testing and whole-genome sequencing were performed to identify environmental heavy metal and antibiotic-resistant genes. Whole-genome sequencing revealed the presence of the and operons, which together formed the copper homeostasis and silver resistance island. The silver resistance gene sequences varied. Various heavy metal resistance genes, including and , were detected in the strains, as were a diverse array of plasmid types, including IncFIB(K) and repB(R1701), and and -lactamase encoding genes. Taken together, the findings underscore the coexistence of silver resistance genes with multiple heavy metal resistance genes in wastewater bacteria, highlighting the environmental implications of silver usage. Efforts should be directed toward restricting silver usage, improving WWTP purification methods to safeguard human and environmental health.
The misuse of silver compounds has led to an increasing presence of silver-resistant microorganisms in the environment, which cannot be completely eliminated in wastewater treatment plants, allowing them to enter the environment and pose risks to environmental safety and human health. However, research on the epidemiology of silver-resistant bacteria in wastewater and their whole-genome sequencing remains limited. Our findings explain that silver-resistant bacteria from the environment often possess resistance to other heavy metals, share genetic similarities, and possess the potential for widespread transmission. Furthermore, these bacteria may enter clinical settings through environmental pathways, posing a risk to human health.
银化合物的过度使用导致了银抗性基因在环境中的传播。然而，关于环境中耐银细菌的流行病学情况却知之甚少。污水处理厂（WWTPs）将临床环境与自然环境联系起来，是银进入自然环境的主要途径。然而，它们在银抗性基因传播中所起的作用仍不清楚。本研究调查了四个污水处理厂附近耐银细菌的特征，以评估它们对环境的影响。从污水处理厂排水口和下游河流采集了水和沉积物样本。通过平板筛选获得的22株耐银菌株中，大多数是[具体菌属1]菌属，其次是[具体菌属2]菌属和[具体菌属3]菌属。值得注意的是，ST23和ST2464是在[具体菌属1]分离株中鉴定出的主要序列类型（多位点序列分型）。进行了抗菌药敏试验和全基因组测序，以鉴定环境重金属和抗生素抗性基因。全基因组测序揭示了存在[具体操纵子1]和[具体操纵子2]操纵子，它们共同构成了铜稳态和银抗性岛。银抗性基因序列各不相同。在这些菌株中检测到了各种重金属抗性基因，包括[具体基因1]和[具体基因2]，以及多种质粒类型，包括IncFIB(K)和repB(R1701)，还有[具体基因3]和β-内酰胺酶编码基因。综上所述，这些发现强调了耐银基因与废水细菌中多种重金属抗性基因的共存，突出了银使用对环境的影响。应致力于限制银的使用，改进污水处理厂的净化方法，以保障人类和环境健康。
银化合物的滥用导致环境中耐银微生物的数量不断增加，这些微生物在污水处理厂中无法被完全消除，从而进入环境并对环境安全和人类健康构成风险。然而，关于废水中耐银细菌的流行病学及其全基因组测序的研究仍然有限。我们的研究结果表明，环境中的耐银细菌通常对其他重金属具有抗性，具有遗传相似性，并且具有广泛传播的潜力。此外，这些细菌可能通过环境途径进入临床环境，对人类健康构成风险。
