Castillo Clarence F G, Ling Maurice H T
School of Information Technology, Republic Polytechnic, Singapore 738964.
School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459 ; Department of Zoology, The University of Melbourne, VIC 3010, Australia.
Biomed Res Int. 2014;2014:648389. doi: 10.1155/2014/648389. Epub 2014 May 20.
Antibiotics resistance is a serious biomedical issue as formally susceptible organisms gain resistance under its selective pressure. There have been contradictory results regarding the prevalence of resistance following withdrawal and disuse of the specific antibiotics. Here, we use experimental evolution in "digital organisms" to examine the rate of gain and loss of resistance under the assumption that there is no fitness cost for maintaining resistance. Our results show that selective pressure is likely to result in maximum resistance with respect to the selective pressure. During deselection as a result of disuse of the specific antibiotics, a large initial loss and prolonged stabilization of resistance are observed, but resistance is not lost to the stage of preselection. This suggests that a pool of partial persists organisms persist long after withdrawal of selective pressure at a relatively constant proportion. Hence, contradictory results regarding the prevalence of resistance following withdrawal and disuse of the specific antibiotics may be a statistical variation about constant proportion. Our results also show that subsequent reintroduction of the same selective pressure results in rapid regain of maximal resistance. Thus, our simulation results suggest that complete elimination of specific antibiotics resistance is unlikely after the disuse of antibiotics once a resistant pool of microorganisms has been established.
抗生素耐药性是一个严重的生物医学问题，因为原本敏感的生物体在其选择压力下会产生耐药性。关于特定抗生素停用后耐药性的流行情况，存在相互矛盾的结果。在这里，我们利用“数字生物体”中的实验进化来研究在假设维持耐药性没有适应性代价的情况下耐药性获得和丧失的速率。我们的结果表明，选择压力可能导致相对于选择压力的最大耐药性。在因特定抗生素停用而进行非选择过程中，观察到耐药性最初大幅下降并长期稳定，但耐药性不会降至预选阶段。这表明一部分持续存在的生物体在去除选择压力后很长时间内以相对恒定的比例持续存在。因此，关于特定抗生素停用后耐药性流行情况的相互矛盾的结果可能是围绕恒定比例的统计变化。我们的结果还表明，随后重新引入相同的选择压力会导致最大耐药性迅速恢复。因此，我们的模拟结果表明，一旦建立了耐药微生物库，抗生素停用后不太可能完全消除特定抗生素耐药性。
