Abstract

GRACIA-VALENZUELA, M.H.; ARIAS MOSCOSO, J.L.; OCHOA MEZA, A.R.  and  ESCOBEDO-BONILLA, César. M.. In vitro evaluation of the antimicrobial activity of two types of oregano (Lippia berlandieri) essential oils against bacteria from shrimp ponds. Revista bio ciencias [online]. 2022, vol.9, e1344.  Epub Apr 12, 2024. ISSN 2007-3380.  https://doi.org/10.15741/revbio.09.e1344.

The antimicrobial activity of Mexican oregano (Lippia berlandieri) essential oils (OEOs) was evaluated against bacteria inhabiting shrimp ponds. One OEO had higher thymol content and another had higher carvacrol content, both compounds have antimicrobial properties. Bacterial isolates (n = 19) were collected in shrimp farms, from shrimp hepatopancreas, pond water and/or sediments. The genus Pseudomonas was the most frequent as it was found in four out of 13 sampled farms and was mainly isolated from hepatopancreas. All the isolates were used to evaluate the antimicrobial effect of five antibiotics and the two OEOs by inhibition zone tests. The antimicrobial activity of the two OEOs was statistically significant against seven bacterial species, compared to the other antibiotics (P < 0.007143). The bacterial species sensitive to the thymol-rich OEO were Serratia marcescens, Proteus vulgaris and Salmonella spp., whereas Enterobacter cloacae, Serratia marcescens and Salmonella typhi were susceptible to the carvacrol-rich OEO. The thymol-rich OEO had significantly higher antibacterial effect than oxytetracycline, magnamycin, aviflox and enrofloxacin, whereas the carvacrol-rich OEO outperformed oxytetracycline and magnamycin. In conclusion, the two OEOs evaluated had higher antibacterial properties than most antibiotics used in this study.

Keywords : Oregano essential oils; thymol; carvacrol; antimicrobial effect; shrimp farms.

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