In Vitro Antimicrobial Activity of Lepechinia caulescens and Sagina procumbens Extracts Against Multidrug-Resistant Salmonella from Meat Sources

Salmonellosis is a major food safety concern, especially when Salmonella strains from meat show multidrug resistance. This study examined plant-derived extracts' antimicrobial potential. Extracts from Lepechinia caulescens (brenilla) and Sagina procumbens (pearl grass) were tested against multidrug-resistant Salmonella from meat in Guanajuato, Mexico. Of 25 strains, 9 were from chicken, 8 from beef, and 8 from pork. This study analyzed three extracts: two from L. caulescens—one isolated from leaves, flowers, and seeds (LCLFS) and the other from stems and roots (LCSR)—and a third extract from S. procumbens (SP). The plant material was dried, ground, and macerated in ethanol for one week in the dark at room temperature. It was then filtered, concentrated, and resuspended in sterile distilled water. The methodology involved performing minimum inhibitory concentration (MIC) tests and antimicrobial susceptibility testing using the disk diffusion method. The inhibition zones of the L. caulescens extracts (17–23 mm in diameter) yielded better results than those of S. procumbens (5–16 mm in diameter). The two extracts, LCLFS and LCSR, exhibited similar inhibitory concentrations of 30 µL/mL, whereas that of S. procumbens was 50 µL/mL. The LCSR extract consistently inhibited Salmonella strains present in all types of meat, unlike the SP extract. Statistical analysis showed that the type of extract and the source of Salmonella significantly affected the results. The LCLFS extract shows promise for the control of multidrug-resistant Salmonella in meat products.