Antibiotic resistance containment strategies at wastewater treatment plants need to be supported by a firm knowledge on the behavior of resistant bacteria within a diverse microbial population in the presence of trace amount of antibiotics. In this study via investigating the population dynamics of resistant/sensitive Staphylococcus aureus co-cultures in several model wastewater matrix systems, valuable insights were obtained into the effect of trace amount of antibiotics (piperacillin and erythromycin) on bacteria, and into the suitability of advanced oxidation treatment (electron beam irradiation) as a remediation measure. It appears that environmentally relevant concentration levels of the antibiotic present in a wastewater matrix leads to a shift in the population in favor of the sensitive subtype, presumably on account of triggering protective biochemical processes in the resistant mutant, which confer no selective advantage since the sensitive strain remains unaffected in this concentration range. The impact of these conditions on the population dynamics can be diminished by using advanced oxidation treatment, considering that degradation products from the wastewater matrix constituents (such as humic acid) might also have an effect. Furthermore, it became also apparent that the presence of trace amount of antibiotics while triggers biological processes in the resistant subtype, concomitantly makes the bacteria more sensitive towards the attack of free radicals during advanced oxidation treatment. The behavior of resistant bacteria under environmental conditions at the cellular and population level clearly merits more attention.

废水处理厂的抗生素耐药性遏制策略需要有关于在存在痕量抗生素的情况下不同微生物种群中耐药细菌行为的牢固知识的支持。在这项研究中，通过调查耐药/敏感的金黄色葡萄球菌的种群动态在几种模型废水基质系统中进行共培养，获得了关于微量抗生素（哌拉西林和红霉素）对细菌的影响以及先进氧化处理（电子束辐照）作为补救措施的适用性的宝贵见解。看来，废水基质中存在的与环境相关的抗生素浓度水平会导致种群向敏感亚型转移，这可能是由于触发了抗性突变体中的保护性生化过程，这没有赋予选择性的优势，因为敏感在此浓度范围内，菌株保持不受影响。通过使用高级氧化处理，可以减少这些条件对种群动态的影响，考虑到废水基质成分的降解产物（如腐殖酸）也可能会产生影响。此外，很明显的是，微量抗生素的存在虽然在抗性亚型中触发了生物过程，但同时也使细菌对高级氧化处理过程中的自由基攻击更加敏感。在细胞和群体水平的环境条件下，耐药细菌的行为显然值得更多关注。