Department of Civil and Environmental Engineering, National University of Singapore, Block E2-02-13, 1 Engineering Drive 3, Singapore, 117576, Singapore.
Appl Microbiol Biotechnol. 2014 Mar;98(6):2667-73. doi: 10.1007/s00253-013-5205-2. Epub 2013 Sep 27.
Wastewater treatment plants (WWTPs) are major collection pools of antibiotics of which low concentrations may induce antibiotic resistance in their microbial communities and pose threat to human health. However, information is still limited on the microbial community alteration in WWTPs upon exposure to low-dose antibiotics due to absence of negative control systems without input of resistant bacteria and resistance genes. Here we report the impact of trace erythromycin (ERY) and dehydrated erythromycin (ERY-H2O) on microbial community dynamics in three long-term (1 year) running sequencing batch reactors (SBRs), R1 (ERY-H2O), R2 (ERY), and negative control R3. The PhyloChip microarray analysis showed that ERY-H2O and ERY significantly altered their microbial communities based on bacterial richness (e.g., 825 operational taxonomic units (OTUs) in R1, 699 OTUs in R2, and 920 OTUs in R3) and population abundance (15 and 48 subfamilies with >80 % abundance decrease in R1 and R2, respectively). ERY-H2O and ERY have broad but distinct antimicrobial spectrums. For example, bacteria of all the major phyla (i.e., Proteobacteria, Actinobacteria, Bacteroidetes, and Chloroflexi) present in SBRs were severely inhibited by ERY-H2O and ERY, but bacteria of Acidobacteria, Chlorobi, Firmicutes, Nitrospira and OP10 phyla were only inhibited by ERY. Very limited bacterial groups showed antibiotic resistance to ERY-H2O or ERY through forming biofilms (e.g., Zoogloea) or synthesizing resistant proteins (e.g., Thauera, Candidatus Accumulibacter, Candidatus Competibacter, and Dechloromonas) in the SBRs. Inhibition was observed to be the main effect of ERY-H2O and ERY on microbial communities in the reactors. The results would broaden our knowledge of effects of low-dose antibiotics on microbial communities in WWTPs.
污水处理厂（WWTPs）是抗生素的主要聚集地，其中低浓度的抗生素可能会在微生物群落中诱导抗生素耐药性，从而对人类健康构成威胁。然而，由于缺乏没有耐药菌和抗性基因输入的阴性对照系统，因此对于 WWTP 中暴露于低剂量抗生素后微生物群落的变化，信息仍然有限。在这里，我们报告了痕量红霉素（ERY）和脱水红霉素（ERY-H2O）对三个长期（1 年）运行的序批式反应器（SBR）中微生物群落动态的影响，R1（ERY-H2O）、R2（ERY）和阴性对照 R3。PhyloChip 微阵列分析显示，ERY-H2O 和 ERY 基于细菌丰富度（例如，R1 中有 825 个操作分类单元（OTUs），R2 中有 699 个 OTUs，R3 中有 920 个 OTUs）和种群丰度（ERY-H2O 和 ERY 分别使 15 和 48 个亚科的丰度下降 80%以上）显著改变了它们的微生物群落。ERY-H2O 和 ERY 具有广泛但不同的抗菌谱。例如，SBR 中所有主要门（即变形菌门、放线菌门、拟杆菌门和绿弯菌门）的细菌均被 ERY-H2O 和 ERY 严重抑制，但酸杆菌门、绿菌门、厚壁菌门、硝化螺旋菌门和 OP10 门的细菌仅被 ERY 抑制。在 SBR 中，非常有限的细菌群通过形成生物膜（例如，动胶菌）或合成抗性蛋白（例如，陶厄氏菌、未命名的拟杆菌门候选菌、未命名的竞争杆菌门候选菌和脱氯单胞菌）对 ERY-H2O 或 ERY 表现出抗生素耐药性。在反应器中，抑制被观察到是 ERY-H2O 和 ERY 对微生物群落的主要作用。研究结果将拓宽我们对 WWTP 中低剂量抗生素对微生物群落影响的认识。
