摘要

      微型塑料已成为新兴的污染物，并成为有害细菌的潜在载体，而有关微型塑料表面的抗生素抗性细菌（ARB）和抗生素抗性基因（ARGs）的紧急和传播的信息却很少。本研究探讨了海水培养体系中ARB，特别是多抗生素耐药菌（MARB）在微塑料表面的富集情况。聚对苯二甲酸乙二醇酯在收集的微型塑料中所占比例最高（75%）。微塑性样品中可培养ARB的含量为6.40 × 106-2.48 ××108 cfu/g，是水样的100-5000倍。微塑性样品中可培养ARB与可培养细菌总数之比高于水样。高通量测序表明，微塑性样品中可培养ARB的多样性和丰度较高，以弧菌属、鼠尾菌属和芸香属为主。共获得160株MARB分离物，其中大部分来自微塑性样品。抗4种和3种抗生素的MARB菌株在微塑性样品中所占比例较高，对青霉素、磺胺呋喃唑、红霉素和四环素的耐药率较高。优势多重耐药谱为TET-SFX-ERY-PEN，在微塑性和水样中分别占25.4%和23.9%。在典型的MARB菌株中，ARGs在微塑性样品中的阳性检出率高达80.0%，而在水样中的阳性检出率为65.3%。在微塑性样品中检测到5种1类整合子（intI1）相关基因盒阵列和7种基因盒，均高于水样。这些结果表明，微塑料对ARB尤其是超级细菌的富集和耐药性的传播是有害的。

      Microplastics have become emerging pollutants and served as potential vectors for harmful bacteria, while rare information on the emergency and propagation of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) on the surface of microplastics is available. This study investigated the enrichment of ARB, especially multi-antibiotic resistant bacteria (MARB), on the surface of microplastics in mariculture system. Polyethylene terephthalate accounted for the highest proportion (75%) in the collected microplastics. The counts of cultivable ARB in microplastic samples were 6.40 × 10⁶–2.48 × 10⁸ cfu/g, which were 100–5000 times higher than those in water samples. The ratios of cultivable ARB to total cultivable bacteria from microplastic samples were higher than those from water samples. High-throughput sequencing showed that the diversity and abundance of cultivable ARB in the microplastic samples was high with the predominant bacterial genera of Vibrio, Muricauda and Ruegeria. Total 160 MARB isolates were obtained and most of isolates were obtained from the microplastic samples. MARB isolates resisting or intermediating to four and three antibiotics accounted for much higher proportions in the microplastic samples, and the higher percentage of antibiotic resistance was to penicillin, sulfafurazole, erythromycin and tetracycline. The dominant multiple antibiotic resistance profile was TET-SFX-ERY-PEN, which accounted for 25.4% in microplastic samples and 23.9% in water samples. In typical MARB isolates, the positive detection rate of ARGs was up to 80.0% in microplastic samples while that was 65.3% in water samples. Five types of class 1 integrons (intI1) associated gene cassette arrays and seven types of gene cassettes were detected in microplastic samples, which were more than those in water samples. These results revealed that microplastics were hazardous pollutants for the enrichment of ARB, especially superbugs, and the spread of antibiotic resistance.

      https://www.sciencedirect.com/science/article/pii/S0147651319311832