Mechanism of Antibacterial Activities of a Rice Hull Smoke Extract (RHSE) against Multidrug ‐Resistant Salmonella Typhimurium In Vitro and in Mice

AbstractThe present study tested antibacterial activity of a rice hull smoke extract (RHSE) against a multidrug‐resistant strain of Salmonella Typhimurium and examined its mode of suppressive action in vitro and in mice. In vitro studies showed that the minimum inhibitory concentration (MIC) value of RHSE was 1.29% (v/v). The inactivation was confirmed by complete loss of cell viability in the range of 104 to 107 colony forming units of the resistant Salmonella Typhimurium strain. Agarose and sodium dodecyl sulfate–polyacrylamide gel electrophoreses were used to evaluate the integrities of bacterial genomic DNA and total cellular protein profiles. The antibacterial action of RHSE results from a leakage of intracellular macromolecules following rupture of bacterial cells. Scanning electron microscopy of the cells shows that RHSE also induced deleterious morphological changes in the bacterial cell membrane of the pathogens. In vivo antibacterial activity of RHSE at a 1 × MIC concentration was examined in a bacterial gastroenteritis model using Balb/c mice orally infected with the Salmonella Typhimurium. The results show greatly decreased excretion of the bacteria into the feces and suppressed translocation of the bacteria to internal organs (cecum, mesenteric lymph node, spleen, and liver) compared with the infected mice not subjected to the RHSE treatment. Collectively, the present findings indicate that the mechanism of the antibacterial activities both in vitro and in t...
Source: Journal of Food Science - Category: Food Science Authors: Tags: Food Microbiology & Safety Source Type: research