Antibacterial and antibiofilm activities and synergism with florfenicol from the essential oils of Lippia sidoides and Cymbopogon citratus against Aeromonas hydrophila

Abstract

Aims Aeromonas hydrophila is an opportunistic bacterium, with a high capacity for biofilm production, which can cause severe damage in aquaculture. The objective of this study was to identify the chemical compounds of the essential oils of Lippia sidoides (EOLS) and Cymbopogon citratus (EOCC), and to evaluate the biocidal, antibiofilm and synergistic action with the antimicrobial florfenicol of these essential oils (EOs) against A. hydrophila. Methods and Results The antibacterial activity of EOLS and EOCC was verified by the minimum bactericidal concentration and by the action of these EOs against both forming and consolidated biofilms. The synergistic activity of EOs with florfenicol was performed using the checkerboard technique. The main component of EOLS and EOCC was carvacrol (44.50%) and α‐citral (73.56%), respectively. Both EOs showed weak inhibitory activity (≥3125.00 µg ml−1). Two bacterial isolates were able to produce biofilm, and EOLS and EOCC acted upon the bacterial isolates to prevent biofilm formation. A bactericidal effect was verified for EOLS in the previously consolidated biofilm for both isolates and for EOCC in only one of the isolates. In general, EOLS had a synergistic effect with florfenicol, while EOCF had an additive effect. Conclusions Both EOs were able to interfere with biofilm formation and did not have an antagonistic effect in combination with florfenicol. The best results were found for EOLS, which showed a synergistic effect with florfenicol and the ability to interfere in the formation of consolidated biofilm. Significance and Impact of the Study This study highlights the potential of EOLS and EOCC to interfere in biofilm and act in synergy with florfenicol to reduce the occurrence of A. hydrophila. Development of these compounds may contribute to the development of herbal medicines in aquaculture.

Addition of essential oil from lemongrass to the tambaqui ( Colossoma macropomum ) diet: Effects on growth, intestinal enzymes, haematological and metabolic variables, and antimicrobial challenge

“…In previous studies, EOCC had been demonstrated to reduce the occurrence of A. hydrophila in vitro (Al-Sagheer et al, 2018;Felix e Silva et al, 2022). In addition, essential oils from C. flexuosus and Cymbopogon nardus improved potential in vivo disease resistance against A. hydrophila in Nile tilapia and gilthead seabream (Sparus aurata) respectively (De Souza et al, 2020;García-Márquez et al, 2021).…”

“…After extraction, EOCC was stored in an amber bottle at −4°C. Its main constituents were α-citral (73.56%), myrcene (12.65%) and geraniol (3.51%) (Felix e Silva et al, 2022).…”

“…In this sense, the use of essential oils in the diet has been considered a preventive practice because it helps to increase zootechnical parameters (Acar et al, 2015; Chung et al, 2020; Chung, Ribeiro, Melo, et al, 2021; De Souza et al, 2019, 2020; Diler et al, 2016); reduce hyperglycemia (Souza et al, 2019, 2020); and improve haematological (Chung, Ribeiro, Melo, et al, 2021; Ribeiro, Castelo, et al, 2016; Ribeiro, Freitas, et al, 2016; Saei et al, 2016), biochemical (Chung, Ribeiro, Teixeira, & Copatti, 2021; Lopes et al, 2019; Souza et al, 2020), immunological (Baba et al, 2016; Sutili, Murari, et al, 2016; Sutili, Velasquez, et al, 2016; Al‐Sagheer et al, 2018) and intestinal enzyme (De Souza et al, 2020; Souza et al, 2019; Zhang et al, 2020) responses. Essential oils may also represent an alternative to synthetic antibiotics in aquaculture (Felix e Silva et al, 2022). Antibiotics have been used commonly against bacterial pathogens and as growth promoters in fish (Hernandez‐Serrano, 2005).…”

Macrobrachium rosenbergii fed with essential oil from Lippia alba in the diet in low and high stocking density

“…Essential oils can be used as nutritional additives in fish and crustaceans, showing promising results for welfare and growth (Cagol et al, 2020; De Souza et al, 2020; Souza et al, 2020) and represent a viable alternative to synthetic antibiotics (Felix e Silva et al, 2022). Among the different types of essential oils available on the market, essential oil from L. alba (here called EOLA) is one of the most commercialized in South America.…”

“…Essential oils can be used as nutritional additives in fish and crustaceans, showing promising results for welfare and growth (Cagol et al, 2020;De Souza et al, 2020;Souza et al, 2020) and represent a viable alternative to synthetic antibiotics (Felix e Silva et al, 2022).…”