title: Exposure of the grass shrimp, Palaemonetes pugio, to antimicrobial compounds affects associated Vibrio bacterial density and development of antibiotic resistance.
abstract: Antimicrobial compounds are widespread, emerging contaminants in the aquatic environment and may threaten ecosystem and human health. This study characterized effects of antimicrobial compounds common to human and veterinary medicine, aquaculture, and consumer personal care products [erythromycin (ERY), sulfamethoxazole (SMX), oxytetracycline (OTC), and triclosan (TCS)] in the grass shrimp Palaemonetes pugio. The effects of antimicrobial treatments on grass shrimp mortality and lipid peroxidation activity were measured. The effects of antimicrobial treatments on the bacterial community of the shrimp were then assessed by measuring Vibrio density and testing bacterial isolates for antibiotic resistance. TCS (0.33 mg/L) increased shrimp mortality by 37% and increased lipid peroxidation activity by 63%. A mixture of 0.33 mg/L TCS and 60 mg/L SMX caused a 47% increase in shrimp mortality and an 88% increase in lipid peroxidation activity. Exposure to SMX (30 mg/L or 60 mg/L) alone and to a mixture of SMX/ERY/OTC did not significantly affect shrimp survival or lipid peroxidation activity. Shrimp exposure to 0.33 mg/L TCS increased Vibrio density 350% as compared to the control whereas SMX, the SMX/TCS mixture, and the mixture of SMX/ERY/OTC decreased Vibrio density 78-94%. Increased Vibrio antibiotic resistance was observed for all shrimp antimicrobial treatments except for the mixture of SMX/ERY/OTC. Approximately 87% of grass shrimp Vibrio isolates displayed resistance to TCS in the control treatment suggesting a high level of TCS resistance in environmental Vibrio populations. The presence of TCS in coastal waters may preferentially increase the resistance and abundance of pathogenic bacteria. These results indicate the need for further study into the potential interactions between antimicrobials, aquatic organisms, and associated bacterial communities.
authors.affiliation: National Oceanic and Atmospheric Administration, National Ocean Service, National Centers for Coastal Ocean Science, Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina, 29412.
authors.forename: M E
authors.initials: ME
authors.lastname: DeLorenzo
authors.affiliation: Department of Biology, College of Charleston, Charleston, South Carolina, 29412.
authors.forename: J
authors.initials: J
authors.lastname: Brooker
authors.affiliation: National Oceanic and Atmospheric Administration, National Ocean Service, National Centers for Coastal Ocean Science, Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina, 29412.
authors.forename: K W
authors.initials: KW
authors.lastname: Chung
authors.affiliation: Department of Biology, College of Charleston, Charleston, South Carolina, 29412.
authors.forename: M
authors.initials: M
authors.lastname: Kelly
authors.affiliation: Department of Biology, College of Charleston, Charleston, South Carolina, 29412.
authors.forename: J
authors.initials: J
authors.lastname: Martinez
authors.affiliation: National Oceanic and Atmospheric Administration, National Ocean Service, National Centers for Coastal Ocean Science, Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina, 29412.
authors.forename: J G
authors.initials: JG
authors.lastname: Moore
authors.affiliation: Department of Biology, College of Charleston, Charleston, South Carolina, 29412.
authors.forename: M
authors.initials: M
authors.lastname: Thomas
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000633:toxicity*; D017756:Aquaculture; D004352:Drug Resistance, Microbial; D004917:Erythromycin / Q000633:toxicity; D015227:Lipid Peroxidation / Q000187:drug effects; D010118:Oxytetracycline / Q000633:toxicity; D033541:Palaemonidae / Q000187:drug effects* / Q000378:metabolism; D013420:Sulfamethoxazole / Q000633:toxicity; D014260:Triclosan / Q000633:toxicity; D014733:Vibrio / Q000187:drug effects* / Q000254:growth & development; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D000890:Anti-Infective Agents; D014874:Water Pollutants, Chemical; D014260:Triclosan; D004917:Erythromycin; D013420:Sulfamethoxazole; D010118:Oxytetracycline
keywords: Vibrio; antibiotics; resistance; shrimp; toxicity; triclosan