Antibacterial Activity of Lactic Acid ProducingQZ1178 Against Pathogenic.

Abstract

Lactic acid bacteria (LAB) convert carbohydrates into organic acids [mainly lactic acid (LA)], which reportedly have bactericidal activities.is a Gram-negative bacteria which infects birds, and causes significant economic losses. In this study, we investigated the antibacterial activity of the LA producing,QZ1178 from Qula (fermented food), against, using the Oxford cup method. Our data showed thatQZ1178 inhibitedisolates from different origins; however,QZ1178 antibacterial activity dropped dramatically at pH 5.5-pH 6. The LA concentration and pH of the liquid broth containingQZ1178 after 24 h culture was 29 mg/mL and 3.6, respectively. This concentration (29 mg/mL at pH 3.6) and the antibiotic, cefotaxime (minimum inhibitory concentration (MIC) 2.5 μg/mL) effectively inhibited(GAC026) growth as observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).treated with LA exhibited extensive cell surface collapse, increased cell damage, cell membrane disruption, and cytoplasmic leakage, indicative of cell lysis. We suggestQZ1178 exerts potential antibacterial effects against the poultry pathogen,via LA.