Linking the Effect of Antibiotics on Partial-Nitritation Biofilters: Performance, Microbial Communities and Microbial Activities

Effect of Mn-HA on ARGs and MRGs in nitrogen-culturing sludge

The simultaneous escalation in ARGs (antibiotic resistance genes) and MRGs (metal resistance genes) further complicates the intricate network of factors contributing to the proliferation of microbial resistance. Manganese, which has been reported to affect the resistance of bacteria to antibiotics and metals, plays a vital role in microbial nitrogen metabolism. Moreover, nitrifying and denitrifying populations are potential hosts for ARGs. In this study, manganese was introduced in its prevalent organic chelated form in the environment (Manganese humus chelates, Mn-HA) to a N metabolism sludge to explore the effect of manganese on MRGs and ARGs dissemination. Metagenomics results revealed that manganese availability enhances nitrogen metabolism, while a decrease in ARGs was noted which may be attributed to the inhibition of horizontal gene transfer (HGT), reflected in the reduced integrase -encoded gene int. Population analysis revealed that nitrifier and denitrifier genus harbor MRGs and ARGs, indicating that nitrifier and denitrifier are hosts of MRGs and ARGs. This raises the question of whether the prevalence of ARGs is always increased in metal-contained environments.

Metabolic inhibitor-free assessment of the heterotrophic ammonia-oxidizing activity in activated sludge

When the contributions of three ammonia-oxidizing pathways (heterotrophic or autotrophic aerobic ammonia oxidization, and anammox) to wastewater biological nitrogen removal systems was compared by determining their ammonia-oxidizing activities, the key question is how to accurately determine the potential heterotrophic aerobic ammonia-oxidizing (PHAe) activity when the potential autotrophic aerobic ammonia-oxidizing (PAAe) activity (by ammonia-oxidizing bacteria (AOB) or archaea, or complete ammonia oxidization bacteria) also contributes to ammonia oxidization in PHAe activity assay medium. Using a AOB species and three heterotrophic AOB species as inocula, we demonstrated the feasibility of PHAe activity evaluation in the absence of a metabolic inhibitor, i.e., by subtracting the PAAe activity determined in PAAe activity assay medium from a combination of PAAe and PHAe activity determined in PHAe activity assay medium. Binary organic carbon sources (i.e., glucose and acetate) were included in the PHAe activity assay medium to fulfill the carbon requirements of most heterotrophic AOB genera. Higher ammonia-oxidizing activity in AOB biomass than heterotrophic AOB biomass (35.6 vs. 2.6-10.0 mg NH4+-N g-1 MLSS h-1) provides the remarkable advantages of autotrophic aerobic ammonia oxidization in biological nitrogen removal systems. Ammonia removal in three full-scale biological nitrogen removal systems for sewage treatment was predominantly mediated by PAAe activity (1.9-3.3 vs. 0.0-0.3 mg NH4+-N g1 MLSS h-1).

Effects of Florfenicol on nirS-Type Denitrification Community Structure of Sediments in an Aquatic Microcosm Model

Florfenicol is one of the most widely used antibiotics in aquaculture and veterinary clinics because of its low side effects and strong bactericidal effect. A total of 45~60% of florfenicol is not absorbed by the animal body and accumulates in the aquatic environment through a variety of pathways, which affects denitrification. Indoor aquatic microcosm models were constructed and sediment samples were collected at different florfenicol concentrations (0.1, 1, 10, and 100 mg/L) on days 0, 7, 30, and 60 to extract the microbial genome DNA and determine the water properties. qPCR and amplicon sequencing were used to study the dynamic changes in the nirS gene and nirS-type denitrification community structure, diversity, and abundance, respectively. The results showed that high florfenicol stress influenced the sediment's physicochemical properties, reducing conductivity, alkaline dissolved nitrogen, and organic matter content. In addition, the abundance of nirS, a functional denitrification gene, increased obviously with increased florfenicol concentrations but decreased the diversity of nirS-type denitrification microorganisms. Proteobacteria was the dominant denitrifying phylum in the sediment. Our study provides a scientific basis for the rational use of florfenicol in aquaculture to maintain a healthy and stable microecological environment and also provides a preliminary understanding of the response characteristics of water denitrifying microorganisms to florfenicol exposure.

Antibiotics in anaerobic digestion: Investigative studies on digester performance and microbial diversity

The ever-increasing consumption of antibiotics in both humans and animals has increased their load in municipal and pharmaceutical industry waste and may cause serious damage to the environment. Impact of antibiotics on the performance of commercially used anaerobic digesters in terms of bioenergy output, antibiotics' removal and COD removal have been compared critically with a few studies indicating >90% removal of antibiotics. AnMBR performed the best in terms of antibiotic removal, COD removal and methane yield. Most of the antibiotics investigated have adverse effects on microbiome associated with different stages and methane generation pathways of AD which has been assessed using high throughput technologies like metatranscriptomics, metaproteomics and flow cytometry. Perspectives have been given for understanding the fate and elimination of antibiotics from AD. The challenge of optimization and process improvement needs to be addressed to increase efficiency of the anaerobic digesters.

Occurrence of antibiotic resistance genes and multidrug-resistant bacteria during wastewater treatment processes

Wastewater treatment plants (WWTPs) constantly receive a wide variety of contaminants, including pharmaceuticals, and are potential reservoirs of antibiotic resistance genes (ARGs). This favors the development of multidrug-resistant bacteria (MRB) through horizontal gene transfer. Samples from five different WWTP processes were collected in September 2020 and January 2021 to monitor ARG resistomes and culturable MRB in the presence of eight different antibiotics. Nanopore-based ARG abundance and bacterial community analyses suggested that ARG accumulation favors the generation of MRB. Activated and mixed sludges tended to have lower bacterial diversity and ARG abundance because of selective forces that favored the growth of specific microorganisms during aeration processes. Escherichia strains enriched in WWTPs (up to 71%) were dominant in all the samples, whereas Cloacamonas species were highly abundant only in anaerobically digested sludge samples (60%-79%). Two ARG types [sulfonamide resistance genes (sul1) and aminoglycoside resistance genes (aadA1, aadA13, and aadA2)] were prevalent in all the processes. The total counts of culturable MRB, such as Niabella, Enterococcus, Bacillus, and Chryseobacterium species, gradually increased during aerobic WWTP processes. Genomic analyses of all MRB isolated from the samples revealed that the resistome of Enterococcus species harbored the highest number of ARGs (7-18 ARGs), commonly encoding ant(6)-la, lnu(B), erm(B), and tet(S/M). On the other hand, Niablella strains possibly had intrinsic resistant phenotypes without ARGs. All MRB possessed ARGs originating from the same mobile genetic elements, suggesting that WWTPs are hotspots for the migration of ARGs and emergence of MRB.

Cometabolic biodegradation of antibiotics by ammonia oxidizing microorganisms during wastewater treatment processes

Studies on antibiotic removal during wastewater treatment processes are crucial since their release into the environment could bring potential threats to human health and ecosystem. Cometabolic biodegradation of antibiotics by ammonia oxidizing microorganisms (AOMs) has received special attentions due to the enhanced removal of antibiotics during nitrification processes. However, the interactions between antibiotics and AOMs are less well-elucidated. In this review, the recent research proceedings on cometabolic biodegradation of antibiotics by AOMs were summarized. Ammonia oxidizing bacteria (AOB), ammonia oxidizing archaea (AOA) and complete ammonia oxidizers (comammox) played significant roles in both nitrification and cometabolic biodegradation of antibiotics. Antibiotics at varying concentrations might pose inhibiting or stimulating effect on AOMs, influencing the microbial activity, community abundance and ammonia monooxygenase subunit A gene expression level. AOMs-induced cometabolic biodegradation products were analyzed as well as the corresponding pathways for each type of antibiotics. The effects of ammonium availability, initial antibiotic concentration, sludge retention time and temperature were assessed on the cometabolic biodegradation efficiencies of antibiotics. This work might provide further insights into the fate and removal of antibiotics during nitrification processes.

Effect of carrier particle size on enrichment and shift in nitrifier community behaviors for treating increased strength wastewater

In activated sludge systems, adding carriers can improve nitrifier enrichment. Different attachment area induced by different particle sizes of carriers may result in different nitrifier community. This research investigated the effect of different particle sizes of coal ash on nitrifier enrichment treating increased strength wastewater. Results indicated efficient nitrifying coal ash was obtained with smaller coal ash. The ammonia removal rates reached over 98%, which outclassed that in negative control (63.28%), and no nitrite accumulated in these systems under high nitrogen concentration of 1123.35 mg N/L. The high-throughput sequencing assays indicated carriers changed the microbial community structure significantly, thus facilitated the nitrification capacity. Increase abundance of nitrifier has a negative correlation with particle size of carriers. Nitrosomonas became the biggest beneficiary, which maximum composed 50.29% in fillers system and only 13.69% in negative control, whereas the number of Nitrobacter (less than 3.04%) became much lower than ammonia-oxidizing bacteria (AOB). However, the shift of microbial structures, large number of Dokdonella for instance, may guarantee the complete nitrification in systems with smaller carriers. Batch experiments showed a high dissolved oxygen (DO) concentration (4 mg/L) and slightly alkaline condition (pH 8.0) had a positive effect on nitrifying coal ash. PRACTITIONER POINTS: The increase size of nitrifier has a negative correlation with particle size of coal ash. The smaller coal ash reduces the adverse effect of high nitrogen on nitrification. The ammonia removal rate reached 99.82% with influent of 1123.35 mg NH 4 + - N /L in the smallest carriers system.

Predicting antibiotic resistance gene abundance in activated sludge using shotgun metagenomics and machine learning

While the microbiome of activated sludge (AS) in wastewater treatment plants (WWTPs) plays a vital role in shaping the resistome, identifying the potential bacterial hosts of antibiotic resistance genes (ARGs) in WWTPs remains challenging. The objective of this study is to explore the feasibility of using a machine learning approach, random forests (RF's), to identify the strength of associations between ARGs and bacterial taxa in metagenomic datasets from the activated sludge of WWTPs. Our results show that the abundance of select ARGs can be predicted by RF's using abundant genera (Candidatus Accumulibacter, Dechloromonas, Pesudomonas, and Thauera, etc.), (opportunistic) pathogens and indicators (Bacteroides, Clostridium, and Streptococcus, etc.), and nitrifiers (Nitrosomonas and Nitrospira, etc.) as explanatory variables. The correlations between predicted and observed abundance of ARGs (erm(B), tet(O), tet(Q), etc.) ranged from medium (0.400 < R² < 0.600) to strong (R² > 0.600) when validated on testing datasets. Compared to those belonging to the other two groups, individual genera in the group of (opportunistic) pathogens and indicator bacteria had more positive functional relationships with select ARGs, suggesting genera in this group (e.g., Bacteroides, Clostridium, and Streptococcus) may be hosts of select ARGs. Furthermore, RF's with (opportunistic) pathogens and indicators as explanatory variables were used to predict the abundance of select ARGs in a full-scale WWTP successfully. Machine learning approaches such as RF's can potentially identify bacterial hosts of ARGs and reveal possible functional relationships between the ARGs and microbial community in the AS of WWTPs.

Evaluating the nitrogen-contaminated groundwater treatment by a denitrifying granular sludge bioreactor: effect of organic matter loading

A sequential bed granular bioreactor was adapted to treat nitrate-polluted synthetic groundwater under anaerobic conditions and agitation with denitrification gas, achieving very efficient performance in total nitrogen removal at influent organic carbon concentrations of 1 g L^-1 (80-90%) and 0.5 g L^-1 (70-80%) sodium acetate, but concentrations below 0.5 g L^-1 caused accumulation of nitrite and nitrate and led to system failure (30-40% removal). Biomass size and settling velocity were higher above 0.5 g L^-1 sodium acetate. Trichosporonaceae dominated the fungal populations at all times, while a dominance of terrestrial group Thaumarchaeota and Acidovorax at 1 and 0.5 g L^-1 passed to a domination of Methanobrevibacter and an unclassified Comamonadaceae clone for NaAc lower than 0.5 g L^-1. The results obtained pointed out that the denitrifying granular sludge technology is a feasible solution for the treatment of nitrogen-contaminated groundwater, and that influent organic matter plays an important role on the conformation of microbial communities within it and, therefore, on the overall efficiency of the system.

Effects of sulfamethoxazole on coupling of nitrogen removal with nitrification in Yangtze Estuary sediments

Coupling of nitrogen removal processes with nitrification (NR_n) are vital synergistic nitrogen elimination mechanisms in aquatic environments. However, the effects of antibiotics on NR_n are not well known. In the present work, 20-day continuous-flow experiments combined with ¹⁵N tracing techniques and quantitative PCR were performed to simulate the impact of sulfamethoxazole (SMX, a sulfonamide antibiotic) with near in situ concentration on NR_n processes in sediments of Yangtze Estuary. Results showed that SMX with near in situ concentration significantly decreased NR_n, NR_w (uncoupling of nitrogen removal processes with nitrification) and actual nitrogen removal rates via inhibiting nitrogen transformation functional genes (AOB, narG, nirS, nosZ) and anammox 16S rRNA gene, while the coupling links between nitrification and nitrogen removal processes were not broken by the exposure. The proportion of NR_n in total nitrogen removal processes decreased by approximately 10% with SMX addition, due to the different inhibition on AOB, denitrifying genes and anammox 16S rRNA gene. N₂O production and nitrite accumulation remarkably increased with SMX addition under simultaneous nitrification and denitrification, and they strongly correlated with each other. The more severely inhibition on nirS gene (13.6-19.8%) than Nitrospira nxrB gene (0.3-8.2%) revealed that the increased nitrite accumulation with SMX addition mainly occurred in heterotrophic denitrification, suggesting that the increased N₂O production was dominated by the heterotrophic nitrite reduction. Moreover, we estimated that the ratio of external inorganic N eliminated by actual nitrogen removal can upgrade to 6.4-7.4% under circumstances of no inhibition by SMX. This study revealed the effects of SMX with near in situ concentration on NR_n processes and illustrated the microbial mechanism on functional genes level. Our results highlighted the inhibitory effects of SMX on NR_n may contribute to reactive N retention and N₂O production in estuarine and coastal ecosystems.

Interrelationships between tetracyclines and nitrogen cycling processes mediated by microorganisms: A review

Due to their broad-spectrum antibacterial activity and low cost, tetracyclines (TCs) are a class of antibiotics widely used for human and veterinary medical purposes and as a growth-promoting agent for aquaculture. Interrelationships between TCs and nitrogen cycling have attracted scientific attention due to the complicated processes mediated by microorganisms. TCs negatively impact the nitrogen cycling; however, simultaneous degradation of TCs during nitrogen cycling mediated by microorganisms can be achieved. This review encapsulates the background and distribution of TCs in the environment. Additionally, the main nitrogen cycling process mediated by microorganisms were retrospectively examined. Furthermore, effects of TCs on the nitrogen cycling processes, namely nitrification, denitrification, and anammox, have been summarized. Finally, the pathway and microbial mechanism of degradation of TCs accompanied by nitrogen cycling processes were reviewed, along with the scope for prospective studies.

The hybrid system successfully to consisting of activated sludge and biofilter process from hospital wastewater: Ecotoxicological study

This article aimed to demonstrate solution hospital wastewater due to more consumption of antibiotics, public concern has been significantly increased for usage, fates and occurrences of these emerging compounds in the environments and biota. Therefore, it does need more discoveries about occurrences and new treatment methods. Since the conventional treatment methods are low efficient on antibiotics, integration and combination of biological systems together or with an additional process has been shown that provided a better result. However, here, the potential of a full scale combined treating system with activated sludge-scoria biofilter (ASSB) was investigated for removal of ceftriaxone (CEF) and amoxicillin (AMX). To determine the potential biodegradability of proposed system, the solid-water distribution coefficient (K_d) was calculated. Overally, 118 samples were collected from three points; wastewater entering, exiting the activated sludge, and exiting the biofilter. To determine the amount of CEF and AMX antibiotics, the samples were analyzed using HPLC-UV. The results showed that the activated sludge system were able to eliminate the AMX and CEF antibiotics about 70.36 and 84.49%, respectively. In compare to activated sludge, the average mean of ASSB system for the removal efficiency were 87.53% (for AMX) and 93.17% (for CEF), respectively. As a result, it can be found that the efficiency of the combined activated sludge-biofilter system in removing of the low levels of antibiotics was more than individual activated system. The result of K_d revealed that AMX (with a K_d about 0.172) has lower tendency to biomass rather than CEF (with a K_d about 0.512). The ecological toxicity assessment guaranteed there is no risk for fish and daphnia when the activated sludge and also ASSB effluents to be discharged into the environment even without any diluting.

A critical review on the effects of antibiotics on anammox process in wastewater

Anaerobic ammonium oxidation (anammox) has recently become of significant interest due to its capability for cost-effective nitrogen elimination from wastewater. However, anaerobic ammonia-oxidizing bacteria (AnAOB) are sensitive to environmental changes and toxic substances. In particular, the presence of antibiotics in wastewater, which is considered unfavorable to the anammox process, has become a growing concern. Therefore, it is necessary to evaluate the effects of these inhibitors to acquire information on the applicability of the anammox process. Hence, this review summarizes our knowledge of the effects of commonly detected antibiotics in water matrices, including fluoroquinolone, macrolide, β-lactam, chloramphenicol, tetracycline, sulfonamide, glycopeptide, and aminoglycoside, on the anammox process. According to the literature, the presence of antibiotics in wastewater could partially or completely inhibit anammox reactions, in which antibiotics targeting protein synthesis or DNA replication (excluding aminoglycoside) were the most effective against the AnAOB strains.

Norfloxacin-induced effect on enhanced biological phosphorus removal from wastewater after long-term exposure

In this study, long-term experiments were performed under synthetic wastewater conditions to evaluated the potential impacts of norfloxacin (NOR) (10, 100 and 500 μg/L) on enhanced biological phosphorus removal (EBPR). Experimental result showed that long-term exposure to 10 μg/L NOR induced negligible effects on phosphorus removal. The presence of 100 μg/L NOR slightly decreased phosphorus removal efficiency to 94.41 ± 1.59 %. However, when NOR level further increased to 500 μg/L, phosphorus removal efficiency was significantly decreased from 97.96 ± 0.8 5% (control) to 82.33 ± 3.07 %. The mechanism study revealed that the presence of 500 μg/L NOR inhibited anaerobic phosphorus release and acetate uptake as well as aerobic phosphorus uptake during long-term exposure. It was also found that 500 μg/L NOR exposure suppressed the activity of key enzymes related to phosphorus removal but promoted the transformations of intracellular polyhydroxyalkanoate and glycogen. Microbial analysis revealed that that the presence of 500 μg/L NOR reduced the abundances of polyphosphate accumulating organisms but increased glycogen accumulating organisms, as compared the control.

Performance and microbial community structure of an aerobic granular sludge system at different phenolic acid concentrations

The present work aims to use aerobic granular sludge technology for the treatment of wastewater containing high organic matter loads and a mixture of phenolic compounds normally present in olive washing water. The physicochemical performance of five bioreactors treating different concentrations of mixture of phenolic acid was monitored to observe the response of the systems. The bioreactors that operated at 50, 100 and 300 mg L^-1 did not show relevant changes in terms of performance and granules properties, showing high ratio of phenolic compound removal ratio. However, the bioreactors operated with high phenolic compound concentrations showed low rates of organic matter, nitrogen and phenolic acid removal. In the same way, high concentrations of phenolic compounds determined the disintegration of the granular biomass. Next-generation sequencing studies showed a stable community structure in the bioreactors operating with 50, 100 and 300 mg L^-1 of phenolic acids, with the genera Lampropedia and Arenimonas, family Xanthobacteraceae and Fungi Pezizomycotina as the dominant phylotypes. Conversely, the reactors operated at 500 and 600 mg L^-1 of phenolic substances promoted the proliferation of Oligohymenophorea ciliates. Thus, this study suggests that aerobic granular sludge technology could be useful for the treatment of wastewaters such as olive washing water.

Microbial ecology dynamics of a partial nitritation bioreactor with Polar Arctic Circle activated sludge operating at low temperature

A lab-scale partial nitritation SBR was operated at 11 °C for 300 days used for the treatment of high-ammonium wastewater, which was inoculated with activated sludge from Rovaniemi WWTP (located in Polar Arctic Circle) in order to evaluate the influence the temperature on the performance, stability and dynamics of its microbial community. The partial nitritation achieved steady-state long-term operation and granulation process was not affected despite the low temperature and high ammonia concentration. The steady conditions were reached after 60 days of operation where the granular biomass was fully-formed and the 50%-50% of ammonium-nitrite effluent was successful achieved. Inoculation with cold adapted inoculum showed to yield bigger, denser granules with faster start-up without necessity of low temperature adaptation period. Next-generation sequences techniques showed that Trichosporonaceae and Xanthomonadaceae were the dominant OTUs in the mature granules. Our study could be useful in the implementation of full-scale partial nitritation reactors in cold regions such as Nordic countries for treating wastewater with high concentration of ammonium.

Understanding antimicrobial discovery and resistance from a metagenomic and metatranscriptomic perspective: advances and applications

Our inability to cultivate most microorganisms, specifically bacteria, in the laboratory has for many years restricted our view and understanding of the bacterial meta-resistome in all living and nonliving environments. As a result, reservoirs, sources and distribution of antibiotic resistance genes (ARGS) and antibiotic-producers, as well as the effects of human activity and antibiotics on the selection and dissemination of ARGs were not well comprehended. With the advances made in the fields of metagenomics and metatranscriptomics, many of the hitherto little-understood concepts are becoming clearer. Further, the discovery of antibiotics such as lugdinin and lactocillin from the human microbiota, buttressed the importance of these new fields. Metagenomics and metatranscriptomics are becoming important clinical diagnostic tools for screening and detecting pathogens and ARGs, assessing the effects of antibiotics, other xenobiotics and human activity on the environment, characterizing the microbiome and the environmental resistome with lesser turnaround time and decreasing cost, as well as discovering antibiotic-producers. However, challenges with accurate binning, skewed ARGs databases, detection of less abundant and allelic variants of ARGs and efficient mobilome characterization remain. Ongoing efforts in long-read, phased- and single-cell sequencing, strain-resolved binning, chromosomal-conformation capture, DNA-methylation binning and deep-learning bioinformatic approaches offer promising prospects in reconstructing complete strain-level genomes and mobilomes from metagenomes.

Effects of ofloxacin on nitrogen removal and microbial community structure in constructed wetland

Constructed wetlands (CWs) have emerged as a promising technology for the purification of micro-polluted water. However, their nitrogen removal performance can be significantly degraded by design, operational, and environmental factors. The present study investigates the effects of ofloxacin (OFL: 0.1, 10, and 1000 μg L^-1) and plants (Cyperus alternifolius L. and Typha angustifolia L.) on nitrogen removal in a micro-polluted CW system over a duration of 12 weeks. The effects were evaluated by investigating NH₄-N and NO₃-N removal efficiency, nitrification genes (amoA-AOA and amoA-AOB), denitrification genes (nirK and nirS), fungal 18S rRNA gene and microorganism community structure. The results showed that in unplanted CWs, OFL increased the NH₄-N removal efficiency (from 72.6% to 80.7-82.1%), the abundances of amoA-AOA, nirS, nirK and fungal 18S rRNA gene, and the bacterial diversity but decreased the abundance of both amoA-AOB and bacterial richness. In contrast, both the nitrogen removal efficiency (83.4-89.5% for NH₄-N and 33.8-38.5% for NO₃-N) and bacterial diversity/richness were not significantly affected by OFL in planted CWs. In planted systems, OFL increased the relative abundance of Arthrobacter, Pseudomonas, and Enterococcus, which are proven antibiotic-resistant bacteria. This study showed that CWs are able to remove nitrogen from antibiotic-contaminated micro-polluted water, which might primarily be attributed to the presence of plants that protect the microorganism community.

Deciphering of microbial community and antibiotic resistance genes in activated sludge reactors under high selective pressure of different antibiotics

Currently, the effects of high antibiotic concentrations on the performance of microbiota and antibiotic resistance genes (ARGs) in activated sludge (AS) process are not well characterized. Lab-scale batch reactors were performed to evaluate the dynamics of microbial community and ARGs in response to six antibiotics at different concentrations using high-throughput sequencing-based 16S rRNA gene and metagenomic analyses. The presence of antibiotics remarkably decreased the microbial diversity, caused a great change of the microbiota structure, and exerted a selective pressure on the enrichment of potential antibiotic resistant bacteria (ARB), such as Arthrobacter, Thauera, Geothrix, Rudaea, Aridibacter, Conexibacter, Terrimonas, etc. High antibiotic selective pressures increased ARG abundance but simultaneously reduced ARG number. In total, 491 ARG subtypes belonging to 20 ARG types were detected and kanamycin treatment showed the highest ARG abundances. A core set of 54 ARG subtypes that accounted for 66.7%-99.6% of the total ARG abundances were shared by all samples. The increase of the abundances of both corresponding and non-corresponding ARGs under a specific antibiotic treatment revealed the collateral effects of antibiotic selective pressure. Microbial community may play an important role in the composition of ARGs. Network analysis indicated that both internal-type and external-type of ARGs exhibited higher non-random co-occurrence incidences and 18 genera were speculated as the possible hosts for multiple ARGs. This study deciphered the profiles and relationships between microbial community and ARGs in AS process treating wastewater with high antibiotic concentrations and could provide helpful guidance for controlling the development and dissemination of ARB and ARGs.