The shrimp industry in Ecuador is a global powerhouse that significantly contributes to the country’s economy. However, this sector faces a persistent threat from Vibrio bacteria, which form resistant biofilms and cause substantial economic losses. These aquatic pathogens, known for their adaptability and resilience, have become a major obstacle to maintaining shrimp health and productivity.
To combat this issue effectively, it is crucial to understand the factors influencing biofilm formation and to explore alternative antimicrobial strategies such as phages or plant extracts. A study published by scientists from the Universidad San Francisco de Quito USFQ (Ecuador), Clydent S.A., Universidad UTE (Ecuador), and Universidad de Las Américas (UDLA) in the journal PLoS ONE evaluated the impact of temperature, time, and initial inoculum on the development of biofilms of two Vibrio species using a multifactorial experimental design; they then determined the efficacy of eucalyptus and guava leaf extracts in inhibiting and eradicating Vibrio biofilms. These plant extracts were compared with conventional antibiotics to assess their potential as alternatives.
Understanding Vibrio Biofilms: A Complex Problem
Vibrio species are omnipresent in aquatic environments and thrive in warm, saline conditions. Their ability to form biofilms—complex communities encased in a protective matrix—enhances their survival and virulence. Biofilm formation is a sophisticated process influenced by factors such as temperature, time, and bacterial density. Two key Vibrio species, Vibrio parahaemolyticus and Vibrio cholerae, have been identified as major culprits in shrimp diseases.
The Search for Sustainable Solutions
Traditional antibiotics have been employed to combat Vibrio infections, but the rise of antibiotic resistance has necessitated the exploration of alternative approaches. Probiotics and natural products have emerged as promising alternatives, offering a more sustainable and environmentally friendly solution.
Eucalyptus and Guava: Nature’s Antimicrobials
This study focused on the antimicrobial properties of eucalyptus and guava leaf extracts against Vibrio biofilms. These plants, rich in bioactive compounds, have shown antimicrobial activity in previous studies. By evaluating their efficacy against V. parahaemolyticus and V. cholerae under various conditions, the researchers aimed to identify optimal treatment strategies.
Breaking Down Biofilms: A Multifaceted Approach
The research involved characterizing Vibrio biofilm formation under different temperature and time conditions to determine optimal growth parameters. Subsequently, the antimicrobial potential of eucalyptus and guava extracts was evaluated in comparison to standard antibiotics.
The Impact of Environmental Factors on Vibrio Biofilm Formation
This study investigated how temperature, time, and initial inoculum affect the development of biofilms by Vibrio parahaemolyticus and Vibrio cholerae, two species prevalent in shrimp farms. The results revealed optimal conditions for biofilm formation: 24°C and 24 hours for V. parahaemolyticus, and 30°C and 72 hours for V. cholerae. These findings underscore the importance of controlling environmental parameters in aquaculture settings to minimize biofilm development.
The Power of Plant Extracts
Eucalyptus and guava leaf extracts emerged as promising alternatives to antibiotics in combating Vibrio. Chemical analysis identified key compounds in each extract: cipellogin A, B, and C for eucalyptus, and guavinoside A, B, and C for guava. These compounds exhibited potent antimicrobial properties against planktonic Vibrio cells, with eucalyptus extract showing superior efficacy.
Overcoming Biofilm Challenges
The study evaluated the ability of eucalyptus and guava extracts to inhibit and eradicate established Vibrio biofilms. Both extracts significantly reduced biofilm biomass and viable cell counts compared to antibiotics, particularly at higher concentrations. Eucalyptus extract consistently outperformed guava extract and antibiotics in biofilm inhibition and eradication assays.
A Sustainable Solution for Shrimp Aquaculture
The findings of this research highlight the potential of eucalyptus extract as a valuable tool for controlling Vibrio infections in shrimp aquaculture. By effectively targeting both planktonic and biofilm-associated bacteria, eucalyptus extract offers a sustainable and eco-friendly alternative to antibiotics. Further research is needed to optimize the application of eucalyptus extract in aquaculture environments and to assess its long-term impact on shrimp health and productivity.
Conclusion
Understanding the environmental factors that influence Vibrio biofilm formation is essential for developing effective control strategies. This study demonstrates the promising potential of eucalyptus and guava extracts as natural antimicrobials against Vibrio. By incorporating these plant-based solutions into shrimp aquaculture practices, we can reduce dependence on antibiotics, mitigate the risk of antibiotic resistance, and enhance the overall sustainability of the industry.
Contact
Eduardo Tejera
Facultad de Ingeniería y Ciencias Agropecuarias Aplicadas, Grupo de Bioquimioinformática, Universidad de Las Américas (UDLA)
Quito, Ecuador
Email: eduardo.tejera@udla.edu.ec (ET)
António Machado
Laboratorio de Bacteriología, Colegio de Ciencias Biológicas y Ambientales COCIBA, Instituto de Microbiología, Calle Diego de Robles y Pampite, Universidad San Francisco de Quito USFQ
Quito, Ecuador
Email: amachado@usfq.edu.ec
Reference (open access)
Jara-Medina NR, Cueva DF, Cedeño-Pinargote AC, Gualle A, Aguilera-Pesantes D, Méndez MÁ, et al. (2024) Eco-alternative treatments for Vibrio parahaemolyticus and V. cholerae biofilms from shrimp industry through Eucalyptus (Eucalyptus globulus) and Guava (Psidium guajava) extracts: A road for an Ecuadorian sustainable economy. PLoS ONE 19(8): e0304126. https://doi.org/10.1371/journal.pone.0304126
