1. Efficacy assessment of commercially available natural products and antibiotics, commonly used for mitigation of pathogenic Vibrio outbreaks in Ecuadorian Penaeus (Litopenaeus) vannamei hatcheries.
- Author
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Sotomayor MA, Reyes JK, Restrepo L, Domínguez-Borbor C, Maldonado M, and Bayot B
- Subjects
- Animals, Anti-Bacterial Agents pharmacology, Base Sequence, Biological Products pharmacology, Carboxylic Acids pharmacology, Cell Survival drug effects, Drug Resistance, Microbial drug effects, Ecuador epidemiology, Hemocytes cytology, Hemocytes drug effects, Microbial Sensitivity Tests, Oils, Volatile pharmacology, Penaeidae cytology, Penaeidae drug effects, Phylogeny, Probiotics pharmacology, RNA, Ribosomal, 16S genetics, Treatment Outcome, Vibrio Infections epidemiology, Vibrio Infections virology, Anti-Bacterial Agents therapeutic use, Aquaculture, Biological Products therapeutic use, Disease Outbreaks prevention & control, Penaeidae microbiology, Vibrio drug effects, Vibrio Infections drug therapy, Vibrio Infections prevention & control
- Abstract
Bacterial diseases cause high mortality in Penaeus (Litopenaeus) vannamei postlarvae. Therefore, appropriate application of efficient therapeutic products is of vital importance for disease control. This study evaluated through in vitro analyses the antimicrobial effectiveness of commercial therapeutic products used for P. vannamei bacterial diseases and antibiotics against pathogenic Vibrio strains circulating in Ecuadorian hatcheries. Twenty strains were isolated from 31 larvae samples with high bacterial counts from 10 hatcheries collected during mortality events. The strains virulence was verified through challenge tests with Artemia franciscana nauplii and P. vannamei postlarvae. Through 16S rRNA sequence analysis, strains showed a great similarity to the Vibrio sequences reported as pathogens, with 95% belonging to the Harveyi clade. Through antibiograms and minimal inhibitory concentration (MIC) in vitro tests we found that furazolidone, ciprofloxacin, chloramphenicol, norfloxacin, nalidixic acid, florfenicol, fosfomycin and enrofloxacin inhibited the growth of all or most of the strains. Less efficient antibiotics were penicillin, oxytetracycline and tetracycline. A multiple antibiotic resistance (MAR) index of 0.23 showed some level of resistance to antibiotics, with two MAR prevalent patterns (Penicillin-Oxytetracycline and Penicillin-Oxytetracycline-Tetracycline). From a total of 16 natural products (five probiotics, nine organic acids and two essential oils), only three (one probiotic, one organic acid and one essential oil) were effective to control most of the strains. Shrimp producers can apply relatively simple in vitro analyses, such as those employed in this study, to help take adequate management decisions to reduce the impact of bacterial diseases and increase profit., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
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