Contamination of Sulfonamide Antibiotics and Sulfamethazine-Resistant Bacteria in the Downstream and Estuarine Areas of Jiulong River in Southeast China
Total Page：16
File Type：pdf, Size：1020Kb
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Crossref Environ Sci Pollut Res (2015) 22:12104–12113 DOI 10.1007/s11356-015-4473-z RESEARCH ARTICLE Contamination of sulfonamide antibiotics and sulfamethazine-resistant bacteria in the downstream and estuarine areas of Jiulong River in Southeast China Danyun Ou1 & Bin Chen1 & Renao Bai 1 & Puqing Song1 & Heshan Lin1 Received: 28 December 2014 /Accepted: 30 March 2015 /Published online: 16 April 2015 # The Author(s) 2015. This article is published with open access at Springerlink.com Abstract Surface water samples from downstream and estu- Introduction arine areas of Jiulong River were collected in August 2011 and May 2012 for detecting sulfonamide antibiotic residues The occurrence of antibiotics in aquatic environments is of and isolating sulfamethazine-resistant bacteria. ecotoxicological concern because of potential ecosystem al- Sulfamethazine was detected in all samples in May 2012 at teration. Prolonged exposure to low doses of antibiotics leads an average concentration of 78.3 ng L−1, which was the to selective proliferation of resistant bacteria, which could highest among the nine sulfonamide antibiotics determined. transfer antimicrobial resistance genes to other bacterial spe- Sulfamethazine-resistant bacteria (SRB) were screened using cies (Dantas et al. 2008;LevyandMarshall2004)with antibiotic-containing agar plates. The SRB average abundance difficult-to-predict consequences on human health (Martínez in the samples was 3.69×104 and 2.17×103 CFUs mL−1 in 2008). The potential of these low antibiotic concentrations to August 2011 and May 2012, respectively, and was positively promote antimicrobial resistance has been substantiated by the correlated to sulfamethazine concentration in May 2012. The detection of several antibiotic-resistant bacteria and/or genes 16S rRNA gene sequencing of all the 121 SRB isolates re- in aquaculture sites (Hoa et al. 2011), municipal wastewater vealed high diversity. Furthermore, the SRB isolates exhibited discharges (Schwartz et al. 2003; Volkmann et al. 2004), lake multidrug resistance, with 48.7 % showing resistance to at water (Czekalski et al. 2012), drinking water (Schwartz et al. least three antibiotics. The abundance and persistence of high- 2003), sediment (Pei et al. 2006), and soil environments ly diverse SRB and their multidrug resistance are likely to (Dantas et al. 2008; Hargrave et al. 2008). Aquatic ecosystems demonstrate the transferable pressure from coastal environ- have been proposed as reservoirs of antimicrobial resistance ments on public health. (Biyela et al. 2004), and resistant bacteria in coastal environ- ments can represent a serious environmental issue and a means for the spread and evolution of antibiotic-resistant bac- Keywords Sulfonamides . Sulfamethazine-resistant teria (Young 1993), thus drawing increasing concern in China. bacteria . Bacterial diversity . Drug resistance . Surface water . Sulfonamides are a big family of sulfonamide-related anti- Southeast China biotics commonly used in clinical and veterinary medicine and have drawn increasing attention of researchers in China Responsible editor: Robert Duran and elsewhere (Gutiérrez et al. 2010; Pinna et al. 2012;Zhu et al. 2013). A number of studies have shown that sulfonamide Electronic supplementary material The online version of this article (doi:10.1007/s11356-015-4473-z) contains supplementary material, residues are widespread in the coastal aquatic environment which is available to authorized users. and may pose high ecological risk to estuaries, such as Bohai Bay (Zhang et al. 2013a), Laizhou Bay (Zhang et al. * Bin Chen 2012), Beibu Gulf (Zheng et al. 2012), and so on (Zou et al. [email protected] 2011). In the environment, sulfonamides can bind to dihydropteroate synthase (DHPS) in the bacterium and inhibit 1 Third Institute of Oceanography, State Oceanic Administration, 178 dihydrofolic acid formation which is essential for bacterial Daxue Road, Xiamen 361005, China growth. Sulfonamide resistance in bacteria is mediated by Environ Sci Pollut Res (2015) 22:12104–12113 12105 the horizontal transfer of the foreign dhps gene or a part of it or sulfathiazole, sulfachloropyridazine, sulfadimethoxine, sulfa- by means of plasmids which carry sul-genes encoding alter- monomethoxine, sulfamethoxydiazine, sulfamethazine, sulfa- native drug-resistant variants of the DHPS enzyme (Sköld diazine, sulfisomidine, sulfacetamide, sulfisoxazole, and 2000). Positive relationship between the number of sulfadoxin, were purchased from Sigma-Aldrich Co. (St. sulfonamide-resistant bacteria and the concentrations of sul- Louis, MO, USA). fonamides was examined indicating that sulfonamides could The water samples were filtered through a mixed cellulose induce bacteria to generate corresponding resistance (Na et al. ester filter (GE, Piscataway, NJ, USA), 0.2 g of edetate 13 2014). Sulfonamides could inhibit the bacterial enzyme activ- disodium and 100 ng of recovery indicator C3-caffein were ity and cause a relative community shift towards gram- added to the filtered water samples and the pH was adjusted to negative bacteria and towards an increased proportion of fun- 3.0. The treated water samples were extracted with SPE de- gal biomass in soil (Gutiérrez et al. 2010; Pinna et al. 2012). vices (Sigma-Aldrich Co.) installed with a HLB column Jiulong River is the second largest river in the Fujian (6 mL, 500 mg, Waters, Milford, MA, USA) at a speed of Province, China; this latter province comprising a population <10 mL min−1. The HLB column was pretreated with 6 mL of more than five million people. High concentration of anti- of methanol and 6 mL of acidified purified water (pH=3.0). biotics has been detected in this watershed (Chen et al. 2013; After extraction, the bound component was eluted with 6 mL Zheng et al. 2011). In the present study, we characterized the of methanol and flushed with nitrogen gas, and then 60 % pattern of contamination by measuring the sulfonamide resi- methanol was added to make the volume up to 1 mL and the dues and sulfamethazine-resistant bacteria (SRB) in the down- liquid was filtered through a 0.2-μm filter (Whatman, stream and estuarine areas of Jiulong River during the rainy Piscataway, NJ, USA). The blank (2 L of purified water) and and dry seasons. Furthermore, the diversity and multidrug recovery indicator (dissolved in 100 mL of seawater) were resistance of SRB were also studied. We aimed to draw public also subjected to the same procedure. Qualitative and quanti- attention on the consequence of antibiotics contamination by tative analyses were performed on a Waters Acquity™ Ultra evaluating the impact of sulfonamides residual on aquatic Performance LC (UPLC) (Waters, Milford, MA, USA) and bacterial community based on the occurrence of mass spectrometer Quattro Premier XE MICROMASS sulfonamide-resistant bacteria and their antimicrobial resis- (Waters), with an electrospray tandem mass spectrometer tance. The results presented here are conspicuous since previ- (ESI-MS-MS) using multi-reactive monitoring mode. ous studies addressing impact of sulfonamides on aquatic mi- crobial parameters failed to highlight any significant effect of Enumeration of SRB the sulfonamide on microbial abundance and diversity. The SRB were enumerated by selective cultivation in marine agar 2216E plates (Difco, BD, Franklin Lakes, NJ, USA) Material and methods supplemented with 350 μgmL−1 sulfamethazine. The water samples were serially diluted with axenic seawater and Sample collection 100 μL of each dilution were spread onto each plate. Escherichia coli was spread to agar amended with and without Surface water samples were collected along the downstream sulfamethazine for the validation of the sulfamethazine- and estuarine areas of Jiulong River in August 2011 and supplement agar. All the dilutions were prepared in triplicate May 2012, and the sampling sites are indicated in Fig. 1. and the plates were incubated at 28 °C for 6–7 days. A bacte- For antibiotic analysis, 1 L of each aqueous sample was indi- rial abundance between 30 and 300 CFUs per plate was used vidually collected in 1 N hydrochloric acid pre-treated glass to estimate the abundance of bacteria in the samples, and the bottles. Simultaneously, for SRB enumeration, 0.5 L of the percentage of SRB was calibrated with total bacteria enumer- aqueous sample was individually collected in sterile bags ated on non-selective 2216E agar plates (Gao et al. 2012b). (Nasco, Fort Atkinson, WI, USA). All the samples were put into an ice-packed cooler and transported back to the labora- SRB diversity analysis tory for immediate processing. The SRB colonies were picked up individually and Sulfonamide antibiotics analysis reinoculated into marine 2216E liquid medium and cultured at 28 °C for 1 day. The total DNA was extracted using a The sulfonamide antibiotics in the water samples were ana- bacterial DNA extraction kit (Omega, Norcross, GA, USA) lyzed using ultra-performance liquid chromatography coupled and employed as a template to amplify the 16S rDNA gene with electrospray tandem mass spectrometry (UPLC–MS- with bacterial primers 27f and 1492r (Frank et al. 2008). The MS) (Su et al. 2007). Standard samples of 14 sulfonamides, PCR products were sequenced (Shenggong Ltd., Shanghai, namely, sulfamethoxazole, sulfamethizole, sulfapyridine, China) and sequence information was generated using 12106 Environ Sci Pollut Res (2015) 22:12104–12113 Fig. 1 Sampling