气溶胶中抗生素抗性基因研究进展

抗生素的不合理使用导致细菌耐药问题日趋严峻,给人类健康造成巨大威胁。学者们对抗生素抗性菌和抗生素抗性基因(antibiotic resistance genes, ARGs)在多种环境介质中的环境行为开展了大量研究。气溶胶作为ARGs的潜在储存库,是抗生素抗性基因在环境中的重要传播途径之一。目前缺乏对其来源、传播、人类接触和健康风险系统性的梳理。本文针对人类生活功能场所、养殖场、城市污水处理厂和医院等4类气溶胶研究的典型场所,重点综述了上述4类典型场所中气溶胶ARGs的来源、传播途径及对人体的暴露和对健康的危害,为气溶胶中ARGs的预防和控制提供参考。     

珠三角地区PM2.5浓度估算及其健康效应评估

快速的社会经济发展导致城市出现以PM_2.5为首要污染物的空气污染问题，PM_2.5污染严重危害人群健康。因此，厘清PM_2.5时空分布特征并估算其带来的健康影响，对于PM_2.5的区域联防联控具有重要意义。现有研究中，为弥补地面监测数据的不足，借助机器学习算法估算PM_2.5浓度成为研究热点，此外，基于流行病学研究结果的健康效应模型也被广泛用于评估PM_2.5健康影响的研究中。利用珠江三角洲地区2014-2018年56个空气质量监测站的PM_2.5实时监测数据、气象数据、社会经济数据和归一化植被指数，构建随机森林模型，多要素联合估算2000-2018年监测站点的PM_2.5浓度，并采用克里金插值方法获得PM_2.5浓度的空间分布，在此基础上应用全球暴露死亡（GEMM）模型，评估珠三角地区的PM_2.5健康效应。结果表明：（1）2000-2018年期间，珠三角地区的PM_2.5算术年均浓度维持在35μg/m³左右，呈现"西北-东南"递减空间分异；降水量、温度、风速和水汽压等气象因子对PM_2.5浓度具有负向影响，GDP和人口密度等社会经济因子对PM_2.5浓度具有正向影响。（2）2000-2018年期间，珠三角地区PM_2.5人口加权年均浓度均低于PM_2.5算术年均浓度，表明珠三角地区人口密度和PM_2.5浓度未呈现明显的空间匹配关系，例如肇庆PM_2.5浓度较高但人口密度较低，深圳PM_2.5浓度较低但人口密度较高。（3）2000-2018年期间，珠三角地区PM_2.5污染对于缺血性心脏病和中风的健康影响较显著，而对下呼吸道感染的健康影响较弱。区域PM_2.5相关过早死亡人数逐渐增多，主要集中在PM_2.5浓度和人口密度较高的地区，例如珠三角中心地区，以广州中心城区表现明显。本研究建议珠三角地区加大空气污染治理力度，提高医疗服务水平，同时关注城市人口结构，引导城市人口有序流动迁移，以缓解PM_2.5带来的健康影响，实现城市化的健康发展。     

污水处理厂中四环素和磺胺类抗生素抗性基因的分布、传播及去除

近年来,抗生素滥用造成的抗性基因(ARGs)污染问题引起了人们的关注.四环素及磺胺类抗生素由于价格低廉被广泛使用,大量残留的四环素和磺胺通过各种途径进入污水处理厂,并进一步导致ARGs的污染.为深入了解四环素和磺胺类ARGs的污染及治理现状,本研究对污水处理厂中四环素和磺胺类ARGs的分布情况及传播机制进行了综述,并重点讨论了不同污水处理工艺对ARGs的去除效果.在此基础上,从加大污水处理厂ARGs污染调查、改进污水处理工艺以及探讨ARGs传播机制等方面进行了展望.     

上海某高校新校区中抗生素抗性基因污染状况分析

探究新型环境污染物—抗生素抗性基因（ARGs）在校园环境中的分布状况。通过聚合酶链式反应(PCR)对上海某高校使用5年新校区不同区域污水检查井污泥中8种四环素类、4种磺胺类、7种β-内酰胺类、4种链霉素类和5种氯霉素类ARGs进行定性研究,并利用变性梯度凝胶电泳(DGGE)技术分析污泥中细菌群落的多样性。结果显示,校园各区域中共检出19种ARGs,有8种ARGs的检出率大于50%,其中磺胺类抗性基因sulI、sulII的检出率最高,为100%。实验区及餐饮区的ARGs检出种类最多,均为14种,其次为宿舍区(12种),教学区的ARGs检出最少(8种)。通过DGGE分析细菌群落结构,证明该地区的ARGs分布与细菌多样性无明显关系。新校区使用5年但ARGs污染严重,可能是由于人类活动（尤其是科研活动）对ARGs的产生及扩散存在促进作用。此外,细菌群落多样性与ARGs种类的关系表明ARGs在环境中的迁移可能受到除细菌种类之外其他环境因素的影响。     

2000-2015年中国PM2.5浓度时空分布特征及其城乡差异

近40年来,中国快速经济发展引发较为严重的大气污染,PM_2.5是一种重要的空气污染物,掌握其时空分布规律是对其进行防治的重要前提。基于遥感反演出的PM_2.5浓度数据集,研究了中国2000-2015年PM_2.5浓度的时空分布特征,并基于界定的1376个城镇城区及对应乡村的边界分析了每年PM_2.5浓度值的城乡差异,用线性趋势分析法计算城镇PM_2.5浓度的年际变化速率及显著性。结果表明,研究期内,PM_2.5浓度高于35 μg/m³的面积比例由18.58%增加至32.03%,低于15 μg/m³的面积从43.92%减少到25.12%。PM_2.5污染最严重的地区分布在塔里木盆地、河北南部、河南北部和山东西部。从2000年到2015年,中国绝大多数城镇PM_2.5浓度显著增加,尤其是在东北平原、太行山以东的河北省西南部、燕山以南的北京天津及河北唐山、鲁中南山地丘陵及周围平原地区、华北平原江苏省北部。PM_2.5城乡差异在河北省、山西省两条东北-西南向S形条带区域、浙江省-福建省条带及天山北部绿洲区域较大。研究对PM_2.5高浓度区域、PM_2.5浓度增长较快区域以及城区PM_2.5浓度对乡村影响较大区域进行图示,为中国进一步控制雾霾污染提供一定科学依据。     

寒地校园植物群落对大气细颗粒物浓度的消减作用

近年来随着我国城市的快速发展，空气污染作为城市生态环境破坏的首要问题日益严重。因此探究城市绿地中的植物群落是否能够消减大气细颗粒物浓度及其变化特征成为公众和学者广泛关注的焦点。选取位于寒地城市哈尔滨的东北林业大学作为研究对象，通过对校园PM_2.5浓度进行测定和校园植物群落进行调查，定量地分析不同植物群落对PM_2.5浓度的消减作用、PM_2.5浓度的时间变化规律、PM_2.5浓度与温度和空气相对湿度之间的关系。结果显示：（1）PM_2.5浓度日变化呈"双峰单谷"型，早晚偏高；季节变化是夏季PM_2.5浓度最低，秋季PM_2.5浓度最高。（2）不同结构的植物群落对大气细颗粒物的削减效果略有差异，乔灌草配置型绿地的PM_2.5消减率为30.30%，消减效果最佳；乔草和灌草的PM_2.5消减率分别为14.30%和7.77%，消减效果较差。（3）PM_2.5浓度与温度呈负相关关系，与空气相对湿度呈正相关关系。     

地表植被景观对PM2.5浓度空间分布的影响研究

我国当前城市日益频发的雾霾问题引发公众广泛关注,PM_2.5被认为是雾霾的主要成因。研究认为,在某一区域短时间尺度上（如日）,PM_2.5浓度主要受气象条件影响。但在较长时间尺度上（如季,年）,由于气象条件基本相似,则PM_2.5浓度主要受土地利用特别是地表植被景观的影响。如何耦合地表植被景观格局与PM_2.5浓度信息,定量分析其影响是当前相关科学研究的一个难点,需要引入新思路。首先基于季节气象条件基本相似的科学假设,采用土地利用回归模型分四季高精度模拟PM_2.5浓度空间分布。其次,采用像元二分模型分四季估算研究区植被覆盖度。在此基础上采用随机抽样法通过统计回归模型耦合植被覆盖度与PM_2.5空间分布,定量研究植被覆盖度对PM_2.5分布影响及其尺度效应。研究结果表明：1）植被覆盖度与PM_2.5浓度在本研究选择的空间尺度上,都显著负相关,说明植被覆盖度对PM_2.5具有显著影响;同一个季节不同尺度上,以及不同季节同一尺度上的植被覆盖度对PM_2.5浓度的影响存在一定差异。2）植被覆盖度对PM_2.5浓度的影响方式比较复杂,不同的季节的表现方式不同,总体来说PM_2.5浓度与植被覆盖度曲线回归模型的拟合度高于线性回归模型,说明植被覆盖度对PM_2.5的影响具有非线性特征。3）不同的PM_2.5浓度水平下,植被覆盖度对PM_2.5浓度的影响程度存在差异。PM_2.5浓度越高,植被覆盖度对其浓度的影响越明显。本研究提出的区域尺度耦合地表植被覆盖与PM_2.5浓度的思路与方法,有效的揭示了植被覆盖度对PM_2.5浓度分布的影响方式与尺度效应,为通过优化城市植被缓解大气污染提供一定参考。     

深圳市大气污染时空分布及其与景观格局的关系

气溶胶和臭氧是我国大部分地区的两种主要大气污染物,对城市生态环境和人类身体健康影响严重。以深圳市为研究区,利用大气监测站点提供的监测数据和普通kriging空间插值法,从年、季、月尺度上开展近5年（2015-2019）深圳全市PM_2.5和臭氧的时空分布研究,通过皮尔逊分析和显著性检验从月尺度上分析土地覆盖类型及其景观格局对大气污染的影响。结果表明：（1）近5年内深圳市PM_2.5浓度总体呈现下降趋势,臭氧浓度则先降后升,二者季节性和月度差异显著。（2）PM_2.5和臭氧在年、季、月尺度上空间差异明显,全市PM_2.5浓度整体为西北高、东南低;臭氧浓度西北、东南较高,其余区域相对较低。（3）植被占比的增多对PM_2.5浓度有明显的抑制和调控作用,植被斑块间距离越近,对PM_2.5浓度的调控作用越明显;水体占比的增高会导致臭氧浓度增高和变化幅度增大。研究结果可为城市大气污染防治和景观格局规划管理提供参考。     

粤港澳大湾区PM2.5时空分布特征及其与气象要素的关系

细颗粒物（PM_2.5）污染不仅是现代社会城市化进程中的痛点,也是城市大气环境研究不可忽略的重要焦点。粤港澳大湾区作为世界级城市群,既是城市区域经济社会文化发展的重要体现,更是国家区域发展战略的重要构成与政策实施落脚点,其生态环境的优劣尤其受瞩目。对1999-2016年大湾区地表PM_2.5浓度栅格数据集进行了时空分布特征分析,其中空间自相关分析选取莫兰指数（Moran''I指数）作为度量;并利用多元线性回归模型探讨研究区内PM_2.5与气象要素之间关系。结果表明：粤港澳大湾区1999-2016年历年PM_2.5浓度呈先增加后减小的趋势,2008年为时间拐点,该时间节点之后空气质量显著提高,且1999、2009、2016三年,年平均PM_2.5浓度相似值趋于聚集分布。冷热点分析结果表明：热点区域集中于湾区行政核心区域范围内;冷点集中于核心边缘区域,空气质量较优。利用皮尔森相关分析最终筛选出实际蒸散量（aet）、太阳辐射（srad）、最低温度（tmmn）、蒸汽压（vap）、饱和水汽压差（vpd）、风速（ws）等6个气象因子,利用回归分析判断影响PM_2.5浓度时空分布的显著因子。结果表明：本研究区太阳辐射与PM_2.5浓度关系呈负相关,该结果与其他城市相关研究有较大差异,最小温度与PM_2.5浓度呈正相关,风速与PM_2.5浓度呈负相关,饱和水气压差与PM_2.5浓度呈正相关。     

广州大夫山雨季林内外空气TSP和PM2.5浓度及水溶性离子特征

采用平行同步采样法,于2012年雨季,对广州市大夫山森林公园林内外空气的总悬浮颗粒物(TSP)和细颗粒物(PM_2.5)样品进行了24 h收集,测定了TSP和PM_2.5的质量浓度并分析了样品中水溶性无机离子成分。结果表明:林内外PM_2.5的质量浓度平均值分别为(40.18±10.47)和(55.79±13.01) g/cm³;林内外TSP的质量浓度分别为(101.32 ± 33.19)和(116.61±35.36) g/cm³。林内与林外比,PM_2.5和TSP平均质量浓度都显著减少(P < 0.05),表明森林能显著改善空气环境质量。TSP和PM_2.5中SO₄^2-、Na⁺、NH₄⁺和NO₃^-为水溶性无机离子主要成分,占总离子质量的80%以上,林外这些离子的浓度高于林内(NH₄⁺除外)。这4种离子雨季在空气中的主要存在方式为NaCl、Na₂SO₄、NH₄HSO₄和NH₄NO₃。计算表明,采样期间海盐对大夫山空气TSP和PM_2.5的水溶性组分中Na⁺和Cl^-贡献最大,其它元素主要源自陆地源。林内外TSP和PM_2.5的c(NO₃^-)/c(SO₄^2-)比值在0.3以下,表明固定源是大夫山森林公园空气主要污染贡献者,TSP中c(NO₃^-)/c(SO₄^2-)的比值大于PM_2.5的比值,说明移动源对TSP的贡献大于PM_2.5。     

Metagenomic Profiling of Antibiotic Resistance Genes and Mobile Genetic Elements in a Tannery Wastewater Treatment Plant

Antibiotics are often used to prevent sickness and improve production in animal agriculture, and the residues in animal bodies may enter tannery wastewater during leather production. This study aimed to use Illumina high-throughput sequencing to investigate the occurrence, diversity and abundance of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in aerobic and anaerobic sludge of a full-scale tannery wastewater treatment plant (WWTP). Metagenomic analysis showed that Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria dominated in the WWTP, but the relative abundance of archaea in anaerobic sludge was higher than in aerobic sludge. Sequencing reads from aerobic and anaerobic sludge revealed differences in the abundance of functional genes between both microbial communities. Genes coding for antibiotic resistance were identified in both communities. BLAST analysis against Antibiotic Resistance Genes Database (ARDB) further revealed that aerobic and anaerobic sludge contained various ARGs with high abundance, among which sulfonamide resistance gene sul1 had the highest abundance, occupying over 20% of the total ARGs reads. Tetracycline resistance genes (tet) were highly rich in the anaerobic sludge, among which tet33 had the highest abundance, but was absent in aerobic sludge. Over 70 types of insertion sequences were detected in each sludge sample, and class 1 integrase genes were prevalent in the WWTP. The results highlighted prevalence of ARGs and MGEs in tannery WWTPs, which may deserve more public health concerns.     

Abundances of Tetracycline,Sulphonamide and Beta-Lactam Antibiotic Resistance Genes in Conventional Wastewater Treatment Plants (WWTPs) with Different Waste Load

Antibiotics and antibiotic resistant bacteria enter wastewater treatment plants (WWTPs), an environment where resistance genes can potentially spread and exchange between microbes. Several antibiotic resistance genes (ARGs) were quantified using qPCR in three WWTPs of decreasing capacity located in Helsinki, Tallinn, and Tartu, respectively: sulphonamide resistance genes (sul1 and sul2), tetracycline resistance genes (tetM and tetC), and resistance genes for extended spectrum beta-lactams (bla_oxa-58, bla_shv-34, and bla_ctx-m-32). To avoid inconsistencies among qPCR assays we normalised the ARG abundances with 16S rRNA gene abundances while assessing if the respective genes increased or decreased during treatment. ARGs were detected in most samples; sul1, sul2, and tetM were detected in all samples. Statistically significant differences (adjusted p<0.01) between the inflow and effluent were detected in only four cases. Effluent values for bla_oxa-58 and tetC decreased in the two larger plants while tetM decreased in the medium-sized plant. Only bla_shv-34 increased in the effluent from the medium-sized plant. In all other cases the purification process caused no significant change in the relative abundance of resistance genes, while the raw abundances fell by several orders of magnitude. Standard water quality variables (biological oxygen demand, total phosphorus and nitrogen, etc.) were weakly related or unrelated to the relative abundance of resistance genes. Based on our results we conclude that there is neither considerable enrichment nor purification of antibiotic resistance genes in studied conventional WWTPs.     

Status of pathogens,antibiotic resistance genes and antibiotic residues in wastewater treatment systems

Pathogens are becoming nearly untreatable due to the rise in gaining new resistance against standard antibiotics. Coexistence of microbial pathogens, antibiotics and antibiotic resistant genes (ARGs) in wastewater treatment plants (WWTP) provide favourable conditions for the development of new antibiotic resistant bacteria (ARB); facilitate horizontal gene transfer among pathogens and may also serve as a hotspot for the spread of ARB and genes into the environment. In this study, the current status of wastewater treatment systems in the removal of pathogens, ARGs, and antibiotic residues are discussed. WWTP are efficient in removing pathogens and antibiotic residues to a greater extend during secondary and tertiary treatment processes. Recent studies, however, have shown high variations in the presence of pathogens including ARB as well as antibiotic resistance genes (ARG) in the final effluent. Prolonged sludge retention time (SRT) and hydraulic retention time (HRT) during secondary treatment will facilitate antibiotic removal by adsorption and biodegradation. However, the above conditions can also lead to the enhancement of antibiotic resistance process in microbes. Therefore, optimum conditions for the operation of conventional WWTP for the efficient removal of antibiotics are yet to be established. The removal of antibiotic residues can be accelerated by combining conventional activated sludge (CAS) process with an additional treatment technology involving dosing with ozone. The advanced biological treatment method using membrane bioreactors (MBR) in combination with coagulation reportedly has the best ARG removal efficiency, and removes both ARB and extracellular ARGs. While studies have predicted the fate for ARGs in wastewater treatment plants, the mechanisms of ARGs acquisition remains to be conclusively established. Thus, strategies to investigate the underlying mechanism of acquisition of ARGs within the WWTP are also provided in this review.     

A review of the emergence of antibiotic resistance in bioaerosols and its monitoring methods

Despite significant public health concerns regarding infectious diseases in air environments, potentially harmful microbiological indicators, such as antibiotic resistance genes (ARGs) in bioaerosols, have not received significant attention. Traditionally, bioaerosol studies have focused on the characterization of microbial communities; however, a more serious problem has recently arisen due to the presence of ARGs in bioaerosols, leading to an increased prevalence of horizontal gene transfer (HGT). This constitutes a process by which bacteria transfer genes to other environmental media and consequently cause infectious disease. Antibiotic resistance in water and soil environments has been extensively investigated in the past few years by applying advanced molecular and biotechnological methods. However, ARGs in bioaerosols have not received much attention. In addition, ARG and HGT profiling in air environments is greatly limited in field studies due to the absence of suitable methodological approaches. Therefore, this study comprehensively describes recent findings from published studies and some of the appropriate molecular and biotechnological methods for monitoring antibiotic resistance in bioaerosols. In addition, this review discusses the main knowledge gaps regarding current methodological issues and future research directions.

     

Wastewater pollution differently affects the antibiotic resistance gene pool and biofilm bacterial communities across streambed compartments

Wastewater discharges introduce antibiotic residues and antibiotic‐resistant bacteria (ARB) into surface waters. Both inputs directly affect the streambed resistome, either by exerting a selective pressure that favour the proliferation of resistant phenotypes or by enriching the resident communities with wastewater‐associated ARB. Here, we investigated the impact of raw and treated urban wastewater discharges on epilithic (growing on rocks) and epipsammic (growing on sandy substrata) streambed biofilms. The effects were assessed by comparing control and impact sites (i) on the composition of bacterial communities; (ii) on the abundance of twelve antibiotic resistance genes (ARGs) encoding resistance to β‐lactams, fluoroquinolones, sulphonamides, tetracyclines, macrolides and vancomycin, as well as the class 1 integron‐integrase gene (intI1); (iii) on the occurrence of wastewater‐associated bacteria, including putative pathogens, and their potential linkage to target ARGs. We measured more pronounced effects of raw sewage than treated wastewater at the three studied levels. This effect was especially noticeable in epilithic biofilms, which showed a higher contribution of wastewater‐associated bacteria and ARB than in epipsammic biofilms. Comparison of correlation coefficients obtained between the relative abundance of both target ARGs and operational taxonomic units classified as either potential pathogens or nonpathogens yielded significant higher correlations between the former category and genes intI1, sul1, sul2 and ermB. Altogether, these results indicate that wastewater‐associated micro‐organisms, including potential pathogens, contribute to maintain the streambed resistome and that epilithic biofilms appear as sensitive biosensors of the effect of wastewater pollution in surface waters.     

Particle size distribution of the major Alternaria alternata allergen,Alt a 1, derived from airborne spores and subspore fragments

Fungal fragments are abundant immunoreactive bioaerosols that may outnumber the concentrations of intact spores in the air. To investigate the importance of Alternaria fragments as sources of allergens compared to Alternaria spores, we determined the levels of Alternaria spores and Alt a 1 (the major allergen in Alternaria alternata spores) collected on filters within three fractions of particulate matter (PM) of different aerodynamic diameter: (1) PM_>10, (diameter>10 μm); (2) PM_2.5-10 (2.5–10μm); (3) PM_2.5 (0.12–2.5 μm). The airborne particles were collected using a three stage high-volume ChemVol cascade impactor during the Alternaria sporulation season in Poznań, Poland (30 d between 6 July and 22 September 2016). The quantification of Alt a 1 was performed using the enzyme-linked immunosorbent assay. High concentrations of Alt a 1 were recorded during warm and dry d characterized by high sunshine duration, lack of clouds and high dew point values. Atmospheric concentrations of Alternaria spores correlated significantly (r = 0.930, p < 0.001) with Alt a 1 levels. The highest Alt a 1 was recorded in PM_2.5-10 (66.8 % of total Alt a 1), while the lowest in PM_2.5 (<1.0 %). Significantly more Alt a 1 per spore (>30 %) was observed in PM_2.5-10 than in PM_>10. This Alt a 1 excess may be derived from sources other than spores, e.g. hyphal fragments. Overall, in outdoor air the major source of Alt a 1 are intact Alternaria spores, but the impact of other fungal fragments (hyphal parts, broken spores, conidiophores) cannot be neglected, as they may increase the total atmospheric Alt a 1 concentration.     

Research progress on distribution,migration, transformation of antibiotics and antibiotic resistance genes (ARGs) in aquatic environment

Antimicrobial and antibiotics resistance caused by misuse or overuse of antibiotics exposure is a growing and significant threat to global public health. The spread and horizontal transfer of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) by the selective pressure of antibiotics in an aquatic environment is a major public health issue. To develop a better understanding of potential ecological risks die to antibiotics and ARGs, this study mainly summarizes research progress about: (i) the occurrence, concentration, fate, and potential ecological effects of antibiotics and ARGs in various aquatic environments, (ii) the threat, spread, and horizontal gene transfer (HGT) of ARGs, and (iii) the relationship between antibiotics, ARGs, and ARB. Finally, this review also proposes future research direction on antibiotics and ARGs.     

环境中抗生素抗性基因与I型整合子的研究进展

抗生素抗性基因(Antibiotic resistance genes,ARGs)作为一种新型污染物在不同环境中广泛分布、来源复杂,对生态环境和人类健康造成了很大的潜在风险。同时,Ⅰ型整合子(Int Ⅰ)介导的ARGs水平转移是环境中微生物产生耐药性的重要途径,Ⅰ型整合子整合酶基因(intI1)与ARGs丰度在环境中表现出了较高的正相关性,Int Ⅰ可以作为标记物在一定程度上反映ARGs在环境中的迁移转化规律和人类活动影响程度。本文介绍ARGs与Int Ⅰ在环境中的来源与分布,总结Int Ⅰ介导的ARGs迁移转化机制以及相关研究方法,并展望未来的研究发展趋势。     

The biological and chemical contents of atmospheric particulate matter and implication of its role in the transmission of bacterial pathogenesis

Atmospheric particulate matter (APM) is an environmental hazard that endangers human health and causes a variety of diseases. In this work, the microbial community composition, chemical element composition and antimicrobial resistance gene (ARG) prevalence, along with their relationships with environmental parameters were analysed using APM samples collected in Jinan, China. Pathogenic Klebsiella and Aeromonas were found to be significantly correlated with PM_2.5 and temperature, suggesting their proliferation on APM. PM_2.5 and PM₁₀ have similar microbial community compositions but different chemical element compositions, suggesting they have different origins, which have little impact on microbial community structures. This finding, together with analysis of the timing of microbial community structure changes, suggests that microbial community composition is impacted by anthropic activities. Further investigations showed that rare metals including lanthanides are significantly negatively correlated with pathogens in APM, suggesting their inhibitory role. ARGs were observed for every class of antibiotic except for carbapenems in APM, suggesting high ARG prevalence in APM, and APM functions in transmission of antimicrobial resistance. Results obtained in this study suggest that APM can act as a transmission vehicle for pathogenic bacteria and ARGs and lead to the implication of a new transmission route for bacterial pathogenesis by APM.