Increased Waterborne blaNDM-1 Resistance Gene Abundances Associated with Seasonal Human Pilgrimages to the Upper Ganges River

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• 作者：Z. S. Ahammad ; T. R. Sreekrishnan ; C. L. Hands ; C. W. Knapp ; D. W. Graham
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：March 4, 2014
• 年：2014
• 卷：48
• 期：5
• 页码：3014-3020
• 全文大小：381K
• 年卷期：v.48,no.5(March 4, 2014)
• ISSN：1520-5851

文摘

Antibiotic resistance (AR) is often rooted in inappropriate antibiotic use, but poor water quality and inadequate sanitation exacerbate the problem, especially in emerging countries. An example is increasing multi-AR due to mobile carbapenemases, such as NDM-1 protein (coded by bla_NDM-1 genes), which can produce extreme drug-resistant phenotypes. In 2010, NDM-1 positive isolates and bla_NDM-1 genes were detected in surface waters across Delhi and have since been detected across the urban world. However, little is known about bla_NDM-1 levels in more pristine locations, such as the headwaters of the Upper Ganges River. This area is of particular interest because it receives massive numbers of visitors during seasonal pilgrimages in May/June, including visitors from urban India. Here we quantified bla_NDM-1 abundances, other AR genes (ARG), and coliform bacteria in sediments and water column samples from seven sites in the Rishikesh-Haridwar region of the Upper Ganges and five sites on the Yamuna River in Delhi to contrast bla_NDM-1 levels and water quality conditions between season and region. Water quality in the Yamuna was very poor (e.g., anoxia at all sites), and bla_NDM-1 abundances were high across sites in water (5.4 卤 0.4 log(bla_NDM-1路mL^鈥?); 95% confidence interval) and sediment (6.3 卤 0.7 log(bla_NDM-1路mg^鈥?)) samples from both seasons. In contrast, water column bla_NDM-1 abundances were very low across all sites in the Upper Ganges in February (2.1 卤 0.6 log(bla_NDM-1路mL^鈥?)), and water quality was good (e.g., near saturation oxygen). However, per capita bla_NDM-1 levels were 20 times greater in June in the Ganges water column relative to February, and bla_NDM-1 levels significantly correlated with fecal coliform levels (r = 0.61; p = 0.007). Given that waste management infrastructure is limited in Rishikesh-Haridwar, data imply bla_NDM-1 levels are higher in visitor鈥檚 wastes than local residents, which results in seasonally higher bla_NDM-1 levels in the river. Pilgrimage areas without adequate waste treatment are possible 鈥渉ot spots鈥?for AR transmission, and waste treatment must be improved to reduce broader AR dissemination via exposed returning visitors.