title: Multidrug-resistance and toxic metal tolerance of medically important bacteria isolated from an aquaculture system.
abstract: The use of antimicrobials and toxic metals should be considered carefully in aquaculture and surrounding environments. We aimed to evaluate medically relevant bacteria in an aquaculture system and their susceptibility to antimicrobials and toxic metals. Selective cultures for enterobacteria (ENT), non-fermenting Gram-negative rods (NFR) and Gram-positive cocci (GPC) were obtained from water samples collected in two different year seasons. The isolated bacteria were biochemically identified and antimicrobial and toxic metal susceptibility patterns were determined. Overall, 407 representative strains were recovered. In general, bacteria isolated from fish ponds showed higher multiple antibiotic resistance indices when compared to those isolated from a water-fed canal. Resistance to penicillin and azithromycin was observed more frequently in the GPC group, whereas resistance to ampicillin and ampicillin/sulbactam or gentamicin was observed more frequently in the ENT and NFR groups, respectively. All the isolated bacteria were tolerant to nickel, zinc, chromium and copper at high levels (≥1,024 μg mL(-1)), whereas tolerance to cadmium and mercury varied among the isolated bacteria (2-1,024 μg mL(-1)). Multidrug-resistant bacteria were more frequent and diverse in fish ponds than in the water-fed canal. A positive correlation was observed between antimicrobial resistance and metal tolerance. The data point out the need for water treatment associated with the aquaculture system.
authors.affiliation: Department of Parasitology, Microbiology and Immunology, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, 36036–631, Brazil.
authors.forename: Juliana Alves
authors.initials: JA
authors.lastname: Resende
authors.forename: Vânia L
authors.initials: VL
authors.lastname: Silva
authors.forename: Cláudia Oliveira
authors.initials: CO
authors.lastname: Fontes
authors.forename: Job Alves
authors.initials: JA
authors.lastname: Souza-Filho
authors.forename: Tamara Lopes
authors.initials: TL
authors.lastname: Rocha de Oliveira
authors.forename: Cíntia Marques
authors.initials: CM
authors.lastname: Coelho
authors.forename: Dionéia Evangelista
authors.initials: DE
authors.lastname: César
authors.forename: Cláudio Galuppo
authors.initials: CG
authors.lastname: Diniz
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017756:Aquaculture; D017963:Azithromycin / Q000494:pharmacology; D002104:Cadmium / Q000494:pharmacology; D002857:Chromium / Q000494:pharmacology; D003300:Copper / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D004755:Enterobacteriaceae / Q000187:drug effects / Q000302:isolation & purification; D005839:Gentamicins / Q000494:pharmacology; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D006095:Gram-Positive Cocci / Q000187:drug effects* / Q000302:isolation & purification; D008628:Mercury / Q000494:pharmacology; D008670:Metals / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009532:Nickel / Q000494:pharmacology; D010406:Penicillins / Q000494:pharmacology; D061005:Ponds / Q000382:microbiology*; D013407:Sulbactam / Q000494:pharmacology; D014871:Water Microbiology; D015032:Zinc / Q000494:pharmacology; D018440:beta-Lactam Resistance
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins; D008670:Metals; D010406:Penicillins; D002104:Cadmium; D002857:Chromium; D003300:Copper; D000667:Ampicillin; D009532:Nickel; D017963:Azithromycin; D008628:Mercury; D015032:Zinc; D013407:Sulbactam