Environmental drivers and interaction mechanisms of heavy metal and antibiotic resistome exposed to amoxicillin during aerobic composting

Ning Liu; Gang Li; Ya Su; Yi Zhao; Jun Ma; Guangqun Huang

doi:10.3389/fmicb.2022.1079114

Environmental drivers and interaction mechanisms of heavy metal and antibiotic resistome exposed to amoxicillin during aerobic composting

Front Microbiol. 2023 Jan 4:13:1079114. doi: 10.3389/fmicb.2022.1079114. eCollection 2022.

Authors

Ning Liu^{1

2}, Gang Li^{1

2}, Ya Su³, Yi Zhao⁴, Jun Ma^{1

2}, Guangqun Huang³

Affiliations

¹ Key Laboratory of Urban Environment and Health, Ningbo Urban Environment Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.
² Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo, China.
³ Engineering Laboratory for AgroBiomass Recycling and Valorizing, College of Engineering, China Agricultural University, Beijing, China.
⁴ School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, China.

Abstract

The environmental accumulation and spread of antibiotic resistance pose a major threat to global health. Aerobic composting has become an important hotspot of combined pollution [e.g., antibiotic resistance genes (ARGs) and heavy metals (HMs)] in the process of centralized treatment and resource utilization of manure. However, the interaction mechanisms and environmental drivers of HMs resistome (MRGs), antibiotic resistance (genotype and phenotype), and microbiome during aerobic composting under the widely used amoxicillin (AMX) selection pressure are still poorly understood. Here, we investigated the dynamics of HMs bioavailability and their MRGs, AMX-resistant bacteria (ARB) and antibiotic resistome (ARGs and intI1), and bacterial community to decipher the impact mechanism of AMX by conducting aerobic composting experiments. We detected higher exchangeable HMs and MRGs in the AMX group than the control group, especially for the czrC gene, indicating that AMX exposure may inhibit HMs passivation and promote some MRGs. The presence of AMX significantly altered bacterial community composition and AMX-resistant and -sensitive bacterial structures, elevating antibiotic resistome and its potential transmission risks, in which the proportions of ARB and intI1 were greatly increased to 148- and 11.6-fold compared to the control group. Proteobacteria and Actinobacteria were significant biomarkers of AMX exposure and may be critical in promoting bacterial resistance development. S0134_terrestrial_group was significantly negatively correlated with bla_TEM and czrC genes, which might play a role in the elimination of some ARGs and MRGs. Except for the basic physicochemical (MC, C/N, and pH) and nutritional indicators (NO₃ ^--N, NH₄ ⁺-N), Bio-Cu may be an important environmental driver regulating bacterial resistance during composting. These findings suggested the importance of the interaction mechanism of combined pollution and its synergistic treatment during aerobic composting need to be emphasized.

Keywords: antibiotic resistant bacteria; beta-lactam resistance genes; exchangeable heavy metals; heavy metal resistome; waste utilization.