In the case of a suspected anthrax attack, the United States Food and Drug Administration has a plan to immediately distribute stockpiled antibiotics to the affected population. If performed on a large scale, the amount of antibiotics entering wastewater treatment plants would quickly increase. This influx of drugs would likely be followed by unknown consequences to wastewater treatment plants, downstream ecology, and public health. We therefore investigated the influence of the antibiotic ciprofloxacin on bench scale activated sludge reactors. Reactor performance was unaffected regarding removal of total organics during 14 days of antibiotic loading; however, the reactor microbial community was affected immediately following ciprofloxacin-challenge. Aerobic colony-forming units were initially reduced at 24 h and then recovered after 72 h. Analysis of 16S rRNA gene sequences demonstrated an increased relative abundance of Burkholderiales, Bradyrhizobiaceae, Microbacteriaceae, and Emticicia spp. In addition, ciprofloxacin decreased the Shannon's diversity index and community richness. Further, analysis of randomly selected bacterial isolates demonstrated that the prevalence of multidrug resistance increased in the ciprofloxacin-challenged reactors. These results suggest that an emergency response-associated loading of ciprofloxacin into municipal wastewater treatment plants could alter the activated sludge microbiome and select for multidrug-resistant bacteria.

中文翻译：

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应急计划中环丙沙星的预防将改变废水处理基础设施中的细菌群落

如果怀疑是炭疽病发作，美国食品和药物管理局已制定了一项计划，立即向受影响的人群分发库存的抗生素。如果大规模进行，进入废水处理厂的抗生素数量将迅速增加。药物大量涌入之后，可能会对废水处理厂，下游生态和公共卫生产生未知的后果。因此，我们研究了抗生素环丙沙星对台式规模的活性污泥反应器的影响。在加载抗生素14天后，反应器的性能对于去除有机物总量没有影响。然而，环丙沙星攻击后，反应器微生物群落立即受到影响。有氧菌落形成单位最初在24小时减少，然后在72小时后恢复。Burkholderiales，Bradyrhizobiaceae，Microbacteriaceae和Emticicia spp。此外，环丙沙星降低了香农的多样性指数和社区丰富度。此外，对随机选择的细菌分离株的分析表明，在环丙沙星攻击的反应堆中，多药耐药性的患病率增加。这些结果表明，与应急反应相关的环丙沙星装载到市政废水处理厂中可能会改变活性污泥微生物组，并选择耐多药细菌。