AUTHOR=Yu Meng-Fei , Shu Bizhi , Li Zhixuan , Liu Guihua , Liu Wenzhi , Yang Yuyi , Ma Lin 

TITLE=Co-selective Pressure of Cadmium and Doxycycline on the Antibiotic and Heavy Metal Resistance Genes in Ditch Wetlands

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.820920

DOI=10.3389/fmicb.2022.820920

ISSN=1664-302X

ABSTRACT=<p>Abuse of heavy metals and antibiotics results in the dissemination of metal resistance genes (MRGs) and antibiotic resistance genes (ARGs). Ditch wetlands are important sinks for heavy metals and antibiotics. The relationships between bacterial communities and MRG/ARG dissemination under dual stresses of heavy metals and antibiotics remain unclear. The responses of MRGs and ARGs to the co-selective pressure of cadmium (Cd) and doxycycline (DC) in ditch wetlands were investigated after 7-day and 84-day exposures. In ecological ditches, residual rates of Cd and DC varied from 0.4 to –5.73% and 0 to –0.61%, respectively. The greatest total relative abundance of ARGs was observed in the Cd 5 mg L<sup>–1</sup> + DC 50 mg L<sup>–1</sup> group. A significant level of DC (50 mg L<sup>–1</sup>) significantly reduced the total relative abundances of MRGs at a concentration of 5 mg L<sup>–1</sup> Cd stress. Redundancy analysis indicated that Cd and DC had strong positive effects on most ARGs and MRGs after a 7-day exposure. Meanwhile, the class 1 integron gene (<italic>intI1</italic>) exhibited strong positive correlations with most ARGs and cadmium resistance genes (<italic>czcA</italic>) after an 84-day exposure. Network analysis showed that <italic>Acinetobacter</italic> and <italic>Pseudomonas</italic> were the potential dominant host genera for ARGs and MRGs, and tetracycline resistance genes (<italic>tetA</italic>), <italic>czcA</italic>, and <italic>intI1</italic> shared the same potential host bacteria <italic>Trichococcus</italic> after an 84-day exposure.</p>