北京城区重污染天气空气中β-内酰胺类耐药细菌及耐药基因分布特征

Distribution characteristics of b-lactam resistance bacteria and resistance genes in air during heavy pollution weather in urban Beijing

目的比较北京市污染和非污染天气条件下空气细菌对β-内酰胺类抗生素耐药性差异。方法使用六级安德森采样器及大流量滤膜空气采样其在污染和非污染天气下收集北京市城区空气样品;采样同时记录周围环境因子数据;分离可培养细菌扩增16S rRNA基因并进行序列比对;通过抗微生物敏感性测试进行抗生素耐药性表型检测;采样滤膜洗脱富集后进行宏基因组测序。结果污染天气条件下空气细菌丰度、物种多样性、耐药基因丰度、β-内酰胺类抗性基因丰度均较优良天气更高,可吸入细菌比例在重污染天气升高增比超过10%;异常球菌门细菌丰度在污染天气样本中显著增高;共检出134种ARO,β-内酰胺类抗性基因共26个(19.40%);相对湿度和温度与多个β-内酰胺类耐药基因丰度显著相关。结论在污染天气条件下,空气中细菌及其耐药性问题更加严重,尤其是针对β-内酰胺类抗生素,这对于公共健康可能构成一定的风险,需对空气细菌针对β-内酰胺类抗生素耐药性问题持续关注。

Objective To compare the differences inβ-lactam antibiotic resistance among airborne bacteria under polluted and non-polluted weather conditions in Beijing.Methods Air samples were collected from urban areas of Beijing during polluted and non-polluted weather using a six-stage Andersen sampler and high-flow membrane filters.Environmental factors were recorded during sampling.Cultivable bacteria were isolated,and the 16S rRNA gene was amplified and sequenced for identification.Antibiotic resistance phenotypes were detected through antimicrobial susceptibility testing,and metagenomic sequencing was performed on enriched samples from membrane filter elution.Results Airborne bacterial abundance,species diversity,antibiotic resistance gene abundance,andβ-lactam resistance gene abundance were all higher during polluted weather compared with non-polluted weather.The proportion of inhalable bacteria increased by more than 10%during severe pollution events.The abundance of Firmicutes was significantly elevated in polluted weather samples.A total of 134 antibiotic resistance genes(AROs)were identified,including 26β-lactam resistance genes(19.40%).Humidity and temperature were significantly correlated with the abundance of multipleβ-lactam resistance genes.Conclusion Attention should be paid to the issue of airborne bacteria developing resistance toβ-lactam antibiotics.