Occurrence and Dissipation of the Antibiotics Sulfamethoxazole, Sulfadiazine, Trimethoprim, and Enrofloxacin in the Mekong Delta, Vietnam

Abstract

The Mekong Delta in Vietnam has seen a rapid development and intensification of aquaculture in the last decades, with a corresponding widespread use of antibiotics. This study provides information on current antibiotic use in freshwater aquaculture, as well as on resulting antibiotic concentrations in the aquatic environment of the Mekong Delta. Two major production steps, fish hatcheries and mature fish cultivation, were surveyed (50 fish farm interviews) for antibiotic use. Different water sources, including surface water, groundwater and piped water (164 water samples) were systematically screened for antibiotic residues. To better understand antibiotic fate under tropical conditions, the dissipation behavior of selected antibiotics in the aquatic environment was investigated for the first time in mesocosm experiments. None of the investigated antibiotics were detected in groundwater and piped water samples. Surface water, which is still often used for drinking and domestic purposes by local populations, contained median concentrations of 21 ng L-1 sulfamethoxazole (SMX), 4 ng L-1 sulfadiazine (SDZ), 17 ng L-1 trimethoprim (TRIM), and 12 ng L-1 enrofloxacin (ENRO). These concentrations were lower than the predicted no effect concentrations (PNECs) and minimum inhibitory concentrations (MICs), suggesting limited antibiotic-related risk to aquatic ecosystems in the monitored systems. The dissipation half-lives of the studied antibiotics ranged from <1 to 44 days, depending on the availability of sunlight and sediment. Among the studied antibiotics TRIM was the most persistent in water systems. TRIM was not susceptible to photodegradation, while the dissipation of ENRO and SDZ was influenced by photolysis. The recorded dissipation models gave good predictions of the occurrence and concentrations of TRIM, ENRO and SDZ in surface water. In summary, the currently measured concentrations of the investigated antibiotics are unlikely to cause immediate risks to the aquatic environment, yet the persistence of these antibiotics is of concern and might lead to chronic exposure of aquatic organisms as well as humans.

Aquatic food security: insights into challenges and solutions from an analysis of interactions between fisheries, aquaculture, food safety, human health, fish and human welfare, economy and environment

“…For example, the rapid growth of aquaculture in the Mekong Delta, Vietnam relied on high levels of antibiotic use (Nguyen Dang Giang et al . ). There is the possibility that aquaculture systems relying heavily on antibiotic use may also contribute to human health risks by driving the development of antibiotic resistance in bacteria associated with these aquatic animals, some which may be human pathogens, such as certain Vibrio spp.…”

Formation of inclusion complex of enrofloxacin with 2-hydroxypropyl- β -cyclodextrin

“…It can be used to treat specific infections and against a broad spectrum of Gram-negative and Gram-positive bacteria in both stationary and growth phases of bacterial replication (Scheer, 1987). Its wide in vivo distribution, unique antimicrobial effect, high bioavailability, less toxicity, and side effects, make it one of the most commonly used antibiotics for treatment of various animal infectious diseases, and a desirable antibiotic choice for difficult-to-treat infections, particularly those that need long-term antibiotic treatment (Divers et al, 2008;Ebert et al, 2011;Reyes-Herrera et al, 2011;Jerjomiceva et al, 2014;Lin et al, 2014;Rico et al, 2014;Andrieu et al, 2015;Nguyen Dang Giang et al, 2015;Phillips et al, 2015;Piras et al, 2015;Carrascosa et al, 2017;Foster et al, 2017;Roth et al, 2017;Strze R pa et al, 2017;Zhu et al, 2017;Rico et al, 2018). The bactericidal activity of enrofloxacin is concentration-dependent, with susceptible bacterial cell death occurring within 20-30 minutes of exposure.…”

Synergistic toxicity of some sulfonamide mixtures on Daphnia magna

“…Furthermore, SAs may also be directly released to watercourses as their use is extended to aquaculture in various countries. It is a matter of fact that residues of SAs have been repeatedly detected in the aquatic environment (Boxall et al, 2005;Perret et al, 2006;Xu et al, 2007;García-Galán et al, 2009;Santos et al, 2010;Guedes-Alonso et al, 2013;Giang et al, 2015). For many years, the small crustacean Daphnia magna has been recognised as a keystone species in the food webs of many continental water bodies, and has served as an important model for ecotoxicological research (Seda and Petrusek, 2011).…”