摘要

      抗药性基因（ARGs）存在于海洋和陆地细菌中。众所周知，双壳类动物会积累化学污染物和致病微生物，然而，在摄入含有ARG的细菌后，ARG在双壳类动物体内的去向尚不清楚。结果表明，滤水后蛤蜊消化道中土霉素抗性基因tet（M）的拷贝数迅速增加，24小时添加一个含tet（M）的细菌后，仍保持在96h以上，添加的tet（M）分解率大于99.9%，达到平衡状态。对贻贝消化道和海水的环境采样证实了tet（M）在双壳类中分解的假设，因为tet（M）在海水中以10-5到10-6拷贝/16S的浓度存在，而贻贝中tet（M）大多低于检测限。两个（4月）和三个（7月和10月）个体贻贝的tet（M）呈阳性，浓度相当于海水。因此，我们得出结论，双壳类不会从海水中积累tet（M）。

      Antibiotic resistance genes (ARGs) are found in marine as well as terrestrial bacteria. Bivalves are known to accumulate chemical pollutants and pathogenic microbes, however, the fate of ARGs in bivalves after the intake of ARG-possessing bacteria is not known. Here we show that the copy number of oxytetracycline resistance gene tet(M) increased rapidly in the clam digestive tract by filtering water, then remained constant over 96h in a tank experiment even with the addition of tet(M)-possessing bacteria every 24h. >99.9% of the added tet(M) was decomposed, reaching a balanced state. Environmental sampling of mussel digestive tract and seawater supported the hypothesis that tet(M) was decomposed in bivalves as tet(M) was present in seawater from April to October at a concentration of 10^-5 to 10^-6 copies/16S, whereas tet(M) in mussels was mostly below the detection limit. Two (April) and three (July and October) individual mussels were positive for tet(M) with a concentration equivalent to that of seawater. We therefore conclude that bivalves do not accumulate tet(M) from seawater.

       https://www.ncbi.nlm.nih.gov/pubmed/29627540