1School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia.
3Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia.
Am J Trop Med Hyg. 2021 Mar 8;104(5):1761-1767. doi: 10.4269/ajtmh.20-1222.
Understanding the movement of antimicrobial resistance genes (ARGs) in the environment is critical to managing their spread. To assess potential ARG transport through the air via urban bioaerosols in cities with poor sanitation, we quantified ARGs and a mobile integron (MI) in ambient air over periods spanning rainy and dry seasons in Kanpur, India (n = 53), where open wastewater canals (OWCs) are prevalent. Gene targets represented major antibiotic groups-tetracyclines (tetA), fluoroquinolines (qnrB), and beta-lactams (blaTEM)-and a class 1 mobile integron (intI1). Over half of air samples located near, and up to 1 km from OWCs with fecal contamination (n = 45) in Kanpur had detectable targets above the experimentally determined limits of detection (LOD): most commonly intI1 and tetA (56% and 51% of samples, respectively), followed by blaTEM (8.9%) and qnrB (0%). ARG and MI densities in these positive air samples ranged from 6.9 × 101 to 5.2 × 103 gene copies/m3 air. Most (7/8) control samples collected 1 km away from OWCs were negative for any targets. In comparing experimental samples with control samples, we found that intI1 and tetA densities in air are significantly higher (P = 0.04 and P = 0.01, respectively, alpha = 0.05) near laboratory-confirmed fecal contaminated waters than at the control site. These data suggest increased densities of ARGs and MIs in bioaerosols in urban environments with inadequate sanitation. In such settings, aerosols may play a role in the spread of AR.
了解环境中抗生素耐药基因 (ARGs) 的迁移对于管理其传播至关重要。为了评估在卫生条件较差的城市中，通过城市生物气溶胶经空气传播潜在的 ARG，我们在印度坎普尔（Kanpur）的雨季和旱季期间，对环境空气中的 ARGs 和移动整合子（MI）进行了定量分析（n = 53），该城市存在大量的开放污水渠（OWCs）。基因靶点代表了主要的抗生素类别——四环素（tetA）、氟喹诺酮（qnrB）和β-内酰胺（blaTEM）以及 1 类移动整合子（intI1）。在坎普尔，有超过一半的空气样本（n = 45）位于受粪便污染的 OWCs 附近和 1 公里范围内，其检测到的目标超过了实验确定的检测限（LOD）：最常见的是 intI1 和 tetA（分别占样本的 56%和 51%），其次是 blaTEM（8.9%）和 qnrB（0%）。在这些阳性空气样本中，ARG 和 MI 的密度范围为 6.9×101 至 5.2×103 基因拷贝/m3 空气。从 OWCs 收集的 1 公里远的 8 个对照样本中，有 7 个（7/8）对所有靶点均呈阴性。在将实验样本与对照样本进行比较时，我们发现空气中 intI1 和 tetA 的密度在经实验室确认的受粪便污染水域附近明显更高（P = 0.04 和 P = 0.01，alpha = 0.05），而在对照点则更低。这些数据表明，在卫生条件较差的城市环境中，生物气溶胶中的 ARGs 和 MIs 密度增加。在这种环境中，气溶胶可能在 AR 的传播中发挥作用。
