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为了揭示海陆衔接区环境中抗生素与抗性细菌分布特征及其内在相关性,以莱州湾及其主要入海河流为研究区域,利用HPLC-MS/MS分析样品中15种磺胺类抗生素(SAs)和6种喹诺酮类抗生素(QNs)的浓度,并通过改良的Method 1604(US EPA)评估海水与沉积物中2种典型水传病原微生物大肠杆菌(E.coli)与金黄色葡萄球菌(S.aureus)的抗生素抗性水平,进而探讨该区域水体中抗性菌株的分布特点以及微生物抗性率与相应抗生素浓度的相关性。结果显示,莱州湾水体与沉积物中普遍存在磺胺与喹诺酮类抗生素残留及抗性污染问题。两大类抗生素在水体中平均残留浓度分别为3.89 ng·L~(-1)(SAs)和234.68ng·L~(-1)(QNs),在沉积物中分别为0.91 ng·g~(-1)(SAs)和49.37 ng·g~(-1)(QNs),且分布特征基本呈现自河流向海洋逐渐递减的趋势,说明河流输入是莱州湾抗生素污染的主要来源。在水体中,具有磺胺类抗性的E.coli和S.aureus平均检出量分别达到2 018和4 683 CFU·L~(-1),抗性率范围分别在0%~37.3%和10.6%~45.8%之间;而2种喹诺酮类抗性病原微生物的平均检出量则相对较低,分别为1 315 CFU·L~(-1)(E.coli)和1 461 CFU·L~(-1)(S.aureus),抗性率分别为0%~50.0%和0%~20.8%;此外,相比于E.coli,S.aureus为沉积物中的主要抗性病原微生物,磺胺与喹诺酮类抗性S.aureus检出率均高于80%,平均检出量分别为24CFU·g~(-1)和18 CFU·g~(-1)。相关性分析表明,莱州湾近岸海域水体中磺胺类抗生素浓度与磺胺类抗性微生物总量之间具有良好的线性关系,然而其与微生物抗性率之间并未表现出相似的规律,说明近岸海洋环境中抗生素的残留量不是影响抗性菌株丰度的唯一因素。
In order to reveal the distribution characteristics of antibiotics and resistant bacteria in the interface between sea and land, and its inherent relationship, Laizhou Bay and its main rivers into the study area, the use of HPLC-MS / MS analysis of 15 samples of sulfa antibiotics (SAs) and The concentrations of six quinolone antibiotics (QNs) were determined. Two typical water-borne pathogens, E.coli and S. aureus, in seawater and sediment were evaluated by the modified Method 1604 (US EPA) ) Antibiotic resistance level, and then explore the distribution characteristics of the resistant strains in the water and microbial resistance rate and the corresponding concentration of antibiotics. The results showed that sulfonamides and quinolone antibiotics residues and resistance pollution were common in the water and sediment of Laizhou Bay. The average residual concentrations of the two antibiotics in water were 3.89 ng · L -1 (SAs) and 234.68 ng · L -1 (QNs), respectively, and were 0.91 ng · g -1 -1) (SAs) and 49.37 ng · g -1 (QNs), respectively, and their distributional characteristics showed a trend of decreasing gradually from the river to the ocean, indicating that river input is the main source of antibiotic pollution in the Laizhou Bay. The average detection rates of sulfa-resistant E. coli and S. aureus in water were 2018 and 4683 CFU · L -1, respectively, and the resistance rates ranged from 0% to 37.3% and 10.6 % ~ 45.8%, while the average detection rates of the two quinolone-resistant pathogenic microorganisms were relatively low, which were 1 315 CFU · L -1 and 1 461 CFU · L -1, (-1) (S. aureus), the resistance rates were 0% ~ 50.0% and 0% ~ 20.8% respectively. In addition, compared with E. coli, S. aureus was the main resistant pathogenic microorganism in sediment, The detection rates of sulfanilamide and quinolone resistant S. aureus were higher than 80%, the average detection rates were 24 CFU · g -1 and 18 CFU · g -1, respectively. Correlation analysis showed that there was a good linear relationship between the concentration of sulfa antibiotics and the total amount of sulfonamide-resistant microorganisms in the waters off the coast of Laizhou Bay. However, the correlation between sulfa antibiotics and the rate of microbial resistance did not show a similar pattern Residues of antibiotics in coastal marine environments are not the only factors affecting the abundance of resistant strains.