Antibiotic resistance poses a major global health threat. Understanding emergence and dissemination of antibiotic resistance in environmental media is critical to the design of control strategies. Because antibiotic resistance genes (ARGs) may be aerosolized from contaminated point sources and disseminated more widely in localized environments, we assessed ARGs in aerosols in urban La Paz, Bolivia, where wastewater flows in engineered surface water channels through the densely populated urban core. We quantified key ARGs and a mobile integron (MI) via ddPCR and E. coli spp. as a fecal indicator by culture over two years during both the rainy and dry seasons in sites near wastewater flows. ARG targets represented major antibiotic groups—tetracyclines (tetA), fluoroquinolines (qnrB), and beta-lactams (bla_TEM)—and an MI (intI1) represented the potential for mobility of genetic material. Most air samples (82%) had detectable targets above the experimentally determined LOD: most commonly bla_TEM and intI1 (68% and 47% respectively) followed by tetA and qnrB (17% and 11% respectively). ARG and MI densities in positive air samples ranged from 1.3 × 10¹ to 6.6 × 10⁴ gene copies/m³ air. Additionally, we detected culturable E. coli in the air (52% of samples <1 km from impacted surface waters) with an average density of 11 CFU/m³ in positive samples. We observed decreasing density of bla_TEM with increasing distance up to 150 m from impacted surface waters. To our knowledge this is the first study conducting absolute quantification and a spatial analysis of ARGs and MIs in ambient urban air of a city with contaminated surface waters. Environments in close proximity to urban wastewater flows in this setting may experience locally elevated concentrations of ARGs, a possible concern for the emergence and dissemination of antimicrobial resistance in cities with poor sanitation.

抗生素耐药性对全球健康构成重大威胁。了解环境介质中抗生素抗药性的出现和传播对于控制策略的设计至关重要。由于抗生素抗性基因（ARGs）可能从受污染的点源中被雾化并在局部环境中更广泛地传播，因此我们评估了玻利维亚拉巴斯市区的气溶胶中的ARGs，那里的废水在工程化的地表水通道中通过人口稠密的城市核心地流动。我们通过ddPCR和E. coli spp定量了关键ARG和一个移动整合子（MI）。作为雨后和干旱季节在废水流附近地点两年以上养殖的粪便指标。ARG靶标代表主要的抗生素类群-四环素（tetA），氟喹啉（qnrB），β-​​内酰胺类（bla _TEM）和MI（intI1）代表了遗传物质迁移的潜力。大多数空气样本（82％）的可检测目标高于实验确定的LOD：最常见的是bla _TEM和intI1（分别为68％和47％），其次是tetA和qnrB（分别为17％和11％）。阳性空气样品中的ARG和MI密度范围为1.3×10 ¹至6.6×10 ^4个基因拷贝/ m ³空气。此外，我们检测到可培养的大肠杆菌空气中（52％的样品距受冲击地表水不到1公里），阳性样品的平均密度为11 CFU / m ³。我们观察到bla _TEM的密度随着与受影响地表水的距离增加至150 m而降低。据我们所知，这是第一项对地表水被污染城市大气中的ARG和MI进行绝对定量和空间分析的研究。在这种情况下，靠近城市废水流的环境可能会局部升高ARGs的浓度，这可能是对卫生条件差的城市中抗菌素耐药性的出现和传播的关注。