1. School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China; 2. Key laboratory of Yellow River Water Environment in Gansu Province, Lanzhou 730070, China
Abstract：Chromosomes and plasmids mediate the vertical and horizontal transfer of antibiotic resistance genes (ARGs) in sludge, respectively, which allows ARGs to spread between parents or different bacteria strains, resulting in limited reduction of ARGs during vermicomposting. To address this issue, the effects of vermicomposting on vertical and horizontal transfer of ARGs in sludge were investigated by detecting the abundance changes of ARGs and mobile genetic elements (MGEs) on chromosomes and plasmids during vermicomposting for 20 days, with no addition of earthworms as the control. The results showed that the first 10d was the peak of ARGs transfer in sludge vermicomposting. Except for tetM gene, a significant increase in the abundance of the remaining ARGs in the vermicomposting occurred on both plasmids and chromosomes (P<0.05). Compared with the control, the gene abundances of ermF, ermB, tetX, and sul1on plasmids significantly increased by 1.02-fold, 1.97-fold, 2.43-fold, and 0.75-fold in the vermicomposting (P<0.05), while only ermB on chromosomes significantly increased (P<0.05). Compared with the control, the MGEs abundance of intI1 on plasmids significantly enriched by 1.63-fold in the vermicomposting (P<0.05), while its abundance on chromosomes was diametrically opposite, its abundance in the control was larger than vermicomposting. In the 10~20 d of composting, the abundance of MGEs and total ARGs on chromosomes and plasmids decreased in both treatments, with a faster decrease in the vermicomposting. In addition, the MGEs had a significant positive correlation (P<0.05) with ermF, ermB, and sul2 on plasmids, while no significant correlation among MGEs and all ARGs on chromosomes was recorded during vermicomposting. The redundancy analysis revealed that the changes of ARGs were related to the MGEs and environmental changes during vermicomposting, and the environmental factors such as conductivity, organic matter, ammonia and nitrate had a stronger effect on ARGs and MGEs on plasmids than those on chromosomes. This study suggests that the plasmids carrying MGEs mediated horizontal transfer is a major reason for hardly reducing ARGs in sludge vermicompost.
戴晓虎.我国污泥处理处置现状及发展趋势 [J]. 科学, 2020,72(6): 30-34,4 Dai X. Applications and perspectives of sludge treatment and disposal in China [J]. Science, 2021,72:30-34.
[2]
Yang G, Zhang G, Wang H. Current state of sludge production, management, treatment and disposal in China [J]. Water Research, 2015,78:60-73.
[3]
Guo J, Li J, Chen H, et al. Metagenomic analysis reveals wastewater treatment plants as hotspots of antibiotic resistance genes and mobile genetic elements [J]. Water Research, 2017,123:468-478.
[4]
Liu Z, Klümper U, Liu Y, et al. Metagenomic and metatranscriptomic analyses reveal activity and hosts of antibiotic resistance genes in activated sludge [J]. Environment International, 2019,129:208-220.
[5]
Yang Y, Li B, Zou S, et al. Fate of antibiotic resistance genes in sewage treatment plant revealed by metagenomic approach [J]. Water Research, 2014,62:97-106.
[6]
Huang K, Xia H, Li F, et al. Optimal growth condition of earthworms and their vermicompost features during recycling of five different fresh fruit and vegetable wastes [J]. Environmental Science and Pollution Research, 2016,23(13):13569-13575.
[7]
Sharma K, Garg V K. Vermicomposting: A green technology for organic waste management [M]//Waste to Wealth. Springer, Singapore, 2018:199-235.
[8]
Huang K, Cen J Y, Guan M X, et al. Effects of biochars on the fate of antibiotics and their resistance genes during vermicomposting of dewatered sludge [J]. Journal of Hazardous Materials, 2020,397: 122767.
[9]
Cui G, Fu X, Bhat S A, et al. Temperature impacts fate of antibiotic resistance genes during vermicomposting of domestic excess activated sludge [J]. Environmental Research, 2022:112654.
[10]
Huang K, Xia H, Zhang Y, et al. Elimination of antibiotic resistance genes and human pathogenic bacteria by earthworms during vermicomposting of dewatered sludge by metagenomic analysis [J]. Bioresource Technology, CV 2020,297:122451.
[11]
Cui G, Li F, Li S, et al. Changes of quinolone resistance genes and their relations with microbial profiles during vermicomposting of municipal excess sludge [J]. Science of the Total Environment, 2018, 644:494-502.
[12]
关孟欣,彭兰生,陈景阳,等.玉米芯生物炭对污泥蚯蚓粪中微生物种群及ARGs的影响 [J]. 中国环境科学, 2021,41(6):2744-2751. Guan M, Peng L, Chen J, et al. Effects of corncob biochar on the fate of microbial communities and antibiotics resistance genes during vermicomposting of dewatered sludge [J]. China Environmental Science, 2021,41(6):2744-2751.
[13]
陈景阳,夏慧,黄魁,等.四环素对污泥蚯蚓粪中微生物种群和抗 性基因的影响 [J]. 环境科学, 2019,40(7):3263-3269. Chen J, Xia H, Huang K, et al. Effects of tetracycline on microbial communities and antibiotic resistance genes of vermicompost from dewatered sludge [J]. Environmental Science, 2019,40(7):3263-3269.
[14]
Li B, Qiu Y, Song Y, et al. Dissecting horizontal and vertical gene transfer of antibiotic resistance plasmid in bacterial community using microfluidics [J]. Environment International, 2019,131:105007.
[15]
Ehlers L J, Bouwer E J. RP4 plasmid transfer among species of Pseudomonas in a biofilm reactor [J]. Water Science and Technology, 1999,39(7):163-171.
[16]
Sunde M, Norström M. The prevalence of, associations between and conjugal transfer of antibiotic resistance genes in Escherichia coli isolated from Norwegian meat and meat products [J]. Journal of Antimicrobial Chemotherapy, 2006,58(4):741-747.
[17]
Luo Y, Mao D, Rysz M, et al. Trends in antibiotic resistance genes occurrence in the Haihe River, China [J]. Environmental Science & Technology, 2010,44(19):7220-7225.
[18]
Cummings D E, Archer K F, Arriola D J, et al. Broad dissemination of plasmid-mediated quinolone resistance genes in sediments of two urban coastal wetlands [J]. Environmental Science & Technology, 2011,45(2):447-454.
[19]
Huang K, Xia H, Cui G, et al. Effects of earthworms on nitrification and ammonia oxidizers in vermicomposting systems for recycling of fruit and vegetable wastes [J]. Science of The Total Environment, 2017, 578:337-345.
[20]
Cui G, Bhat S A, Li W, et al. Gut digestion of earthworms significantly attenuates cell-free and-associated antibiotic resistance genes in excess activated sludge by affecting bacterial profiles [J]. Science of the Total Environment, 2019,691:644-653.
[21]
Hait S, Tare V. Optimizing vermistabilization of waste activated sludge using vermicompost as bulking material [J]. Waste Management, 2011,31(3):502-511.
[22]
彭兰生,关孟欣,黄魁,等.蚯蚓摄食污泥对其肠道功能区微生物种群及耐药基因的影响 [J]. 中国环境科学, 2022,42(1):465-473. Peng L, Guang M, Huang K, et al. Effect of excess sludge fed by earthworms on microbial community and antibiotic resistance genes in their intestinal functional area [J]. China Environmental Science, 2022, 42(1):465-473.
[23]
Cáceres R, Malińska K, Marfà O. Nitrification within composting: A review [J]. Waste Management, 2018,72:119-137.
[24]
Xing M, Lv B, Zhao C, et al. Towards understanding the effects of additives on the vermicomposting of sewage sludge [J]. Environmental Science and Pollution Research, 2015,22(6):4644-4653.
[25]
Brackett C C, Singh H, Block J H. Likelihood and mechanisms of cross-allergenicity between sulfonamide antibiotics and other drugs containing a sulfonamide functional group [J]. Pharmacotherapy: The Journal of Human Pharmacology and Drug Therapy, 2004,24(7): 856-870.
[26]
Ramsden S J, Ghosh S, Bohl L J, et al. Phenotypic and genotypic analysis of bacteria isolated from three municipal wastewater treatment plants on tetracycline-amended and ciprofloxacin-amended growth media [J]. Journal of Applied Microbiology, 2010,109(5): 1609-1618.
[27]
Wüst P K, Horn M A, Drake H L. Clostridiaceae and Enterobacteriaceae as active fermenters in earthworm gut content [J]. The ISME Journal, 2011,5(1):92-106.
[28]
Thakuria D, Schmidt O, Finan D, et al. Gut wall bacteria of earthworms: a natural selection process [J]. The ISME journal, 2010, 4(3):357-366.
[29]
Wang H, Li H, Gilbert J A, et al. Housefly larva vermicomposting efficiently attenuates antibiotic resistance genes in swine manure, with concomitant bacterial population changes [J]. Applied and Environmental Microbiology, 2015,81(22):7668-7679.
[30]
李彦媚,赵喜红,徐泽智,徐振波.新型细菌耐药元件—整合子系统 [J]. 中国抗生素杂志, 2012,37(1):1-7. Li Y, Zhao X, Xu Z. Novel antibiotic resistance mechanism-integron system [J]. Chin. J. Antibiot., 2012,37(1):1-7.
[31]
Peiyu J, Jingcao P. Progress in the studies of horizontal transfer of bacteria genetic elements related to antibiotic resistance [J]. Wei Sheng wu xue Tong bao, 2006,33(4):167-171.
[32]
Manoharan R K, Srinivasan S, Shanmugam G, et al. Shotgun metagenomic analysis reveals the prevalence of antibiotic resistance genes and mobile genetic elements in full scale hospital wasteway Cter treatment plants [J]. Journal of Environmental Management, 2021, 296:113270.
[33]
Manoharan R K, Srinivasan S, Shanmugam G, et al. Shotgun metagenomic analysis reveals the prevalence of antibiotic resistance genes and mobile genetic elements in full scale hospital wasteway Cter treatment plants [J]. Journal of Environmental Management, 2021,296: 113270.
[34]
Duan M, Li H, Gu J, et al. Effects of biochar on reducing the abundance of oxytetracycline, antibiotic resistance genes, and human pathogenic bacteria in soil and lettuce [J]. Environmental Pollution, 2017,224:787-795.
[35]
Xia W, Xu T, Qin T, et al. Characterization of integrons and novel cassette arrays in bacteria from clinical isloates in China, 2000~2014 [J]. Journal of Biomedical Research, 2016,30(4):292.
[36]
Petrova M, Gorlenko Z, Mindlin S. Tn5045, a novel integron-containing antibiotic and chromate resistance transposon isolated from a permafrost bacterium [J]. Research in Microbiology, 2011,162(3): 337-345.
[37]
Johnsen A R, Kroer N. Effects of stress and other environmental factors on horizontal plasmid transfer assessed by direct quantification of discrete transfer events [J]. FEMS Microbiology Ecology, 2007, 59(3):718-728.
[38]
Ma Y, Wilson C A, Novak J T, et al. Effect of various sludge digestion conditions on sulfonamide, macrolide, and tetracycline resistance genes and class I integrons [J]. Environmental Science & Technology, 2011,45(18):7855-7861.
[39]
Zhang R, Gu J, Wang X, et al. Contributions of the microbial community and environmental variables to antibiotic resistance genes during co-composting with swine manure and cotton stalks [J]. Journal of Hazardous Materials, 2018,358:82-91.
[40]
Qian X, Sun W, Gu J, et al. Variable effects of oxytetracycline on antibiotic resistance gene abundance and the bacterial community during aerobic composting of cow manure [J]. Journal of Hazardous Materials, 2016,315:61-69.
