Formation of Proteus mirabilis Persister in Chicken under Gentamicin Sulphate Treatment

For understanding the biological characteristics of persister formation of Proteus mirabilis, and control and prevention of bacterial diseases in poultry, Proteus mirabilis PM2658 from chicken was used as materials. Minimum inhibitory of concentrations (MIC) of antibiotics to Proteus mirabilis PM2658 were determined by two-fold dilution method. Under different antibiotic treatments and nutritional conditions, the characteristics of persister formation of Proteus mirabilis were determined by spot-plate protocol. Results showed that MIC of gentamicin sulphate (Gen), cefotaxime sodium (Cef) and ofloxacin (Ofx) to Proteus mirabilis PM2658 were 1.56, 0.78 and 3.13 μg·mL^-1, respectively. Treated by 16×MIC and 100×MIC of Gen, stationary phase of Proteus mirabilis PM2658 could form persister, and the percentages of persister formation were 8.04×10^-4 and 1.03×10^-6, respectively. Moreover, the regularity of peresister formation under antibiotic combinations of 16×MIC Gen-4×MIC Cef, 16×MIC Gen-4×MIC Ofx, 4×MIC Cef-4×MIC Ofx, 16×MIC Gen-4×MIC Cef-4×MIC Ofx was the same as that of single Gen treatment, indicating that persister of Proteus mirabilis PM2658 had multiple drug tolerance. The rate of formation of Proteus mirabilis PM2658 persister in 1/5 LB was higher than those in LB and 1/2 LB under 16×MIC Gen treatment, which separately increased by 17.67 times and 5.05 times, which indicated that the formation of Proteus mirabils PM2658 persister was related to nutrition of environment. The heritage of Proteus mirabilis PM2658 persister did not change, which was further determined after every different treatments mentioned above. Taken together, Proteus mirabilis from chicken do form persister, and characteristics of persister formation depends on specific antibiotic.