Antibiotic concentration and antibiotic-resistant bacteria in two shallow urban lakes after stormwater event

Abstract

Stormwater runoff is generally characterized as non-point source pollution. In the present study, antibiotic concentration and antibiotic susceptibilities of cultivable heterotrophic bacteria were investigated in two small shallow urban lakes before and after strong storm event. Several antibiotics, lactose-fermenting bacteria and cultivable heterotrophic bacteria concentrations increased in surface water and/or surface sediment of two small urban lakes (Lake Xuanwu and Wulongtan) after strong storm event. In general, the frequencies of bacteria showing resistance to nine antibiotics increased after storm event. Based on the 16S rRNA genes of 50 randomly selected isolates from each water sample of two lakes, Aeromonas and Bacillus were dominant genera in samples from two lakes, while genera Proteus and Lysinibacillus were the third abundant genera in Lake Xuanwu and Wulongtu, respectively. Presences of nine antibiotic resistance genes (ARGs) in the 100 isolates were detected and most of these isolates harbored at least two ARGs with different functions. The detection frequency of ARGs in Gram-negative isolates was higher than that in Gram-positive isolates. The most prevalent integron in 100 isolates was int(II) (n = 28), followed by int(I) (n = 17) and int(III) (n = 17). Our results indicate that strong storm events potentially contribute to the transfer of ARGs and antibiotic-resistant bacteria from land-sewer system to the urban Lakes.

Occurrence, Distribution, and Risk Assessment of Antibiotics in a Subtropical River-Reservoir System

“…For the water samples in the river system, the total concentration of antibiotics in the dry season (368.8 ± 66.9 ng/L) was significantly lower than that in the wet-to-dry transition season (567.0 ± 110.3 ng/L) and wet season (636.0 ± 138.8 ng/L) (p < 0.05) (Figure 2), suggesting that frequent rain runoff may contribute to the levels of total concentration especially in the rivers characterized as non-point source pollution watershed (Supplementary Materials Figure S2) [22,[43][44][45]. However, this seasonal variation trend is inconsistent with previous investigations [31,39].…”

Lateral gene transfer, bacterial genome evolution, and the Anthropocene

“…Release of wastewater into the environment disseminates antibiotic resistance genes and mobile elements throughout the natural world . In this manner, antibiotic resistance genes spread into freshwater ecosystems, soils, and wild animals . This phenomenon is now so pervasive that mobile genetic elements associated with resistance phenotypes have been proposed as a general proxy for anthropogenic pollution .…”

What are the effective solutions to control the dissemination of antibiotic resistance in the environment? A systematic review protocol

“…The waste management can contribute to minimize the dissemination of antibiotic resistance before their discharge in the natural compartments [14], e.g., treated wastewater in the aquatic environment, sludge or livestock manure in agricultural soil [13,15]. Diffuse sources such as surface runoff, leaching, could also be considered in the dissemination of antibiotic resistance in the environment [16,17]. Simultaneously, ARGs can be transferred to autochthonous bacteria, depending on the characteristics of the receiving environment [18,19].…”