摘要
      抗生素抗性细菌（ARBs）和抗生素抗性基因（ARGs）作为新型污染物被排放到环境中，增加了水平基因转移（HGT）的风险。然而，很少有研究人员研究空气中ARB失活对HGT风险的影响。本研究主要研究了空气中携带sul基因的大肠杆菌10667的失活以及ARGs的释放和去除。此外，分别以无抗性大肠杆菌GMCC 13373和带有质粒RP4的大肠杆菌DH5α为受体和供体，研究了在微波（MW）和紫外线（UV）照射下HGT和转移频率的潜在机制。带有RP4质粒的大肠杆菌CICC 10667和大肠杆菌DH5α的对数失活值分别高达5.5-log和5.0-log，这与MW辐射下的抗生素敏感菌株大肠杆菌CGMCC 13373（3.4-log）截然不同。在紫外线消毒中，含有RP4质粒的大肠杆菌DH5α在4.4-log时减少，大肠杆菌CGMCC 13373在2.3-log时降低，大肠杆菌CICC 10667在2.1-log时失活。比较了MW照射下与紫外线照射下对ARGs和HGT频率的去除率。MW获得的ARGs去除效率（85.5%）高于UV获得的去除效率（48.2%）。因此，空气中ARGs释放到受体（正向转移）的HGT频率（0.008）降低，低于UV照射下的HGT（0.014）。此外，将质粒RP4从供体转移到存活的受损大肠杆菌10667中，因为细胞渗透性（反向转移）在高HGT频率（0.003）下增加了MW，这接近紫外线（0.002）的值。此外，sul1和sul2基因被证实比sul3基因对MW更具抗性。这些发现揭示了受损的大肠杆菌10667和周围环境微生物之间的HGT机制。微波是一种很有前途的技术，可以对空气中的微生物进行消毒，防止抗生素耐药性的传播。
Abstract
Antibiotic-resistant bacteria (ARBs) and antibiotic-resistant genes (ARGs) as new types of contaminants are discharged into the environment, increasing the risk of horizontal gene transfer (HGT). However, few researchers have examined the impacts of airborne ARB deactivation on HGT risk. The deactivation of airborne Escherichia coli 10667 (carrying sul genes) and the emission and removal of ARGs were mainly investigated in this study. Moreover, the potential mechanisms of HGT and transfer frequencies under microwave (MW) and ultraviolet (UV) irradiation were investigated using the nonresistant E. coli GMCC 13373 and E. coli DH5α with plasmid RP4 as the recipient and donor, respectively. E. coli CICC 10667 and E. coli DH5α with RP4 plasmid achieve log inactivation values as high as 5.5-log and 5.0-log, respectively, which were quite different from the antibiotic-sensitive strain E. coli CGMCC 13373 (3.4-log) subjected to MW irradiation. For UV disinfection, E. coli DH5α with the RP4 plasmid was reduced at 4.4-log, E. coli CGMCC 13373 was reduced at 2.3-log, and E. coli CICC 10667 was inactivated at 2.1-log. The removal rates of ARGs and HGT frequencies under MW irradiation were compared with those under UV irradiation. The ARGs removal efficiency (85.5%) obtained by MW was higher than that obtained by UV (48.2%). Consequently, the HGT frequency (0.008) of airborne ARGs released to the recipient (forward transfer) decreased and was lower than that under UV irradiation (0.014). Moreover, the plasmid RP4 was transferred from the donor to the surviving damaged E. coli 10667 as cell permeability (reverse transfer) was increased at a high HGT frequency (0.003) by MW, which was close to the value by UV (0.002). Additionally, sul1 and sul2 genes were confirmed to be more resistant to MW than the sul3 gene. These findings reveal the mechanism of HGT between damaged E. coli 10667 and surrounding environmental microbes. Microwave is a promising technology for disinfecting airborne microbes and preventing the spread of antibiotic resistance.

https://www.mdpi.com/1660-4601/19/7/4332