@article {110, title = {Occurrences of three classes of antibiotics in a natural river basin: association with antibiotic-resistant Escherichia coli.}, journal = {Environ Sci Technol}, volume = {48}, year = {2014}, month = {2014 Dec 16}, pages = {14317-25}, abstract = {

To investigate the occurrence of antibiotics in urban rivers and their association with antibiotic-resistant Escherichia coli, 20 (fluoro)quinolone antibiotics (FQs), 16 tetracycline antibiotics (TCs) and their degradation products, and 25 sulfonamides (SAs) and some degradation products were determined in 45 river samples and 13 discharged wastewater samples collected from Wenyu River and its tributaries and 4 composite effluent samples from sewage treatment plants in Beijing, China. Fifteen FQs, eight TCs, including four degradation chemicals, and sixteen SAs, including four acetylated products, were detected in the river water. The SAs were the dominant antibiotic (total concentrations up to 3164.0 ng/L) in river water, followed by FQs (1430.3 ng/L) and TCs (296.6 ng/L). The sum concentrations for each class of detected antibiotic in the 13 discharge site samples were higher than those in river samples, up to 12326.7 ng/L for SAs, 6589.2 ng/L for FQs, and 730.1 ng/L for TCs, largely contributing to the high concentrations in the river basin. Log-linear regression analysis confirmed that the concentrations of FQs, TCs, and SAs in the Wenyu River basin were strongly correlated with the number of E. coli resistant to FQs (p \< 0.05), TCs (p \< 0.05), and SAs (p \< 0.05), providing evidence for the environmental impacts of antibiotic usage.

}, keywords = {Anti-Bacterial Agents, China, Drug Resistance, Bacterial, Environmental Monitoring, Escherichia coli, Fluoroquinolones, Rivers, Sulfonamides, Tetracyclines, Waste Water, Water Pollutants, Chemical}, issn = {1520-5851}, doi = {10.1021/es503700j}, author = {Zhang, Qinqin and Jia, Ai and Wan, Yi and Liu, Hong and Wang, Kunping and Peng, Hui and Dong, Zhaomin and Hu, Jianying} } @article {121, title = {Molecular and physiological characterization of fluoroquinolone resistance in relation to uropathogenicity among Escherichia coli isolates isolated from Wenyu River, China.}, journal = {Chemosphere}, volume = {87}, year = {2012}, month = {2012 Mar}, pages = {37-42}, abstract = {

Increasing antibacterial resistance and pathogenicity in the environment is of growing concern due to its potential human risk. In the present study, 236 Escherichia coli isolates were collected from Wenyu River in China on drugless (48 isolates) and quinolone-containing plates (189 isolates). Their minimum inhibitory concentrations (MICs) were determined ranging from 0.125 μg mL(-1) to 128 μg mL(-1). Mutation points related to fluoroquinolone resistance were observed at S83 to L and D87 to N or Y in the GyrA subunit and S80 to R or I and E84 to G in the ParC subunit. Generally, MICs of LEV and GAT are dependent on the patterns of these mutation points. The profile with three mutation points was related to LEV-resistant E. coli isolates, and the (S83L, D87N+S80I) mutation profile was most prevalent (65.7\%) in LEV-resistant isolates, while a large proportion of isolates, even those with three mutation points, were susceptive to GAT. The incidence of virulence factors in LEV-resistant isolates (44.7\%, 59/132) was much higher than in nonresistant isolates (23.1\%, 24/104) (χ(2)=11.925, 1{\textdegree} of freedom, p\<0.001) indicating that fluoroquinolone-resistant E. coli would pose a potential risk. A similar distribution was also found in isolates resistant to GAT (χ(2)=7.843, 1{\textdegree} of freedom, p=0.0079).

}, keywords = {Anti-Bacterial Agents, China, Drug Resistance, Bacterial, Escherichia coli, Fluoroquinolones, Rivers, Water Pollutants, Chemical}, issn = {1879-1298}, doi = {10.1016/j.chemosphere.2011.11.050}, author = {Sun, Jianxian and Hu, Jianying and Peng, Hui and Shi, Jiachen and Dong, Zhaomin} } @article {117, title = {Occurrence and source apportionment of sulfonamides and their metabolites in Liaodong Bay and the adjacent Liao River basin, North China.}, journal = {Environ Toxicol Chem}, volume = {30}, year = {2011}, month = {2011 Jun}, pages = {1252-60}, abstract = {

The presence of antibiotics in the environment is of great concern because of their potential for resistance selection among pathogens. In the present study we investigated the occurrence of 19 sulfonamides, five N-acetylated sulfonamide metabolites, and trimethoprim in the Liao River basin and adjacent Liaodong Bay, China, as well as 10 human/agricultural source samples. Within the 35 river samples, 12 sulfonamides, four acetylated sulfonamides, and trimethoprim were detected, with the dominant being sulfamethoxazole (66.6 ng/L), N-acetylsulfamethoxazole (63.1 ng/L), trimethoprim (29.0 ng/L), sulfadiazine (14.0 ng/L), and sulfamonomethoxine (8.4 ng/L); within the 36 marine samples, 10 chemicals were detected, with the main contributions from sulfamethoxazole (25.2 ng/L) and N-acetylsulfamethoxazole (28.6 ng/L). Sulfamethoxazole (25.9\%), N-acetylsulfamethoxazole (46.6\%), trimethoprim (22.9\%), and sulfapyridine (1.4\%) were the main chemicals from human sources, while sulfamonomethoxine, sulfamethazine, sulfaquinoxaline, sulfaguanidine, sulfadiazine, sulfanilamide, and sulfamethoxypyridazine were dominant in the animal husbandry sources, specifically, swine and poultry farms, and sulfamethoxazole (91\%) was dominant in the mariculture source. A principal component analysis with multiple linear regression was performed to evaluate the source apportionment of total sulfonamides in Liaodong Bay. It was found that animal husbandry contributed 15.2\% of total sulfonamides, while human sources contributed 28.5\%, and combined human and mariculture sources contributed 56.3\%. In addition, the mariculture contribution was 24.1\% of total sulfonamides into the sea based on mass flux estimation. The present study is the first report that the environmental levels of sulfonamide metabolites were comparable to the corresponding parents; therefore, we should pay attention to their environmental occurrence. Source apportionment showed human discharge (60.7\%) significantly contributed to these antibiotics in Liaodong Bay, which provides important information for environmental management.

}, keywords = {Agriculture, Anti-Bacterial Agents, Aquaculture, China, Environmental Monitoring, Humans, Linear Models, Principal Component Analysis, Rivers, Seawater, Spectrometry, Mass, Electrospray Ionization, Sulfamethazine, Sulfamethoxazole, Sulfamethoxypyridazine, Sulfamonomethoxine, Sulfapyridine, Sulfaquinoxaline, Sulfonamides, Tandem Mass Spectrometry, Trimethoprim, Water Pollutants, Chemical, Water Pollution, Chemical}, issn = {1552-8618}, doi = {10.1002/etc.508}, author = {Jia, Ai and Hu, Jianying and Wu, Xiaoqin and Peng, Hui and Wu, Shimin and Dong, Zhaomin} } @article {118, title = {Determination and occurrence of retinoic acids and their 4-oxo metabolites in Liaodong Bay, China, and its adjacent rivers.}, journal = {Environ Toxicol Chem}, volume = {29}, year = {2010}, month = {2010 Nov}, pages = {2491-7}, abstract = {

Retinoic acids (RAs) and their metabolites play an important role in abnormal morphological development and are speculated to be a possible cause for the increased rates of deformities in wild frog populations. In the current study, a method using ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry was developed for simultaneously analyzing all-trans-RA (at-RA), 13-cis-RA (13c-RA), 9-cis-RA (9c-RA), and their 4-oxo metabolites, all-trans-4-oxo-RA (at-4-oxo-RA), 13-cis-4-oxo-RA (13c-4-oxo-RA), and 9-cis-4-oxo-RA (9c-4-oxo-RA) in wastewaters and surface waters. Method detection limits were matrix dependent, ranging from 0.02 to 0.37 ng/L. The method was used to investigate the occurrence of RAs and 4-oxo-RAs in Liaodong Bay and its adjacent rivers. Of these six retinoids, at-RA, 13c-RA, at-4-oxo-RA, and 13c-4-oxo-RA were detected in river waters at detection frequencies of 100\%, 92\%, 48.6\%, and 21.6\%, and concentrations of 0.05 to 1.23 ng/L, less than 0.03 to 0.41 ng/L, less than 0.02 to 1.00 ng/L, and less than 0.06 to 0.81 ng/L, respectively. Retinoic acids were detected for the first time in the aquatic environment and were found to be more persistent than 4-oxo-RAs. The hazard quotient for mortality of frog embryos caused by induction by retinoids detected in the current study was then estimated, and the value was calculated to be 0.09. No retinoid was detected in seawaters.

}, keywords = {China, Chromatography, High Pressure Liquid, Rivers, Spectrometry, Mass, Electrospray Ionization, Stereoisomerism, Tretinoin, Water Pollutants, Chemical}, issn = {1552-8618}, doi = {10.1002/etc.322}, author = {Wu, Xiaoqin and Hu, Jianying and Jia, Ai and Peng, Hui and Wu, Shimin and Dong, Zhaomin} }