ABSTRACT
Objective To probe the oprⅠ gene in rat model with Pseudomonas aeruginosa septicemia by FQ-PCR,and compare the sensitivity and specificity between FQ-PCR and traditional germiculture,and check the change of oprI gene before and after the antibiotic therapy as to rapidly judge its sensitivity.Methods The standard Pseudomonas aeruginosa with five different concentration were prepared,the drug-sensitive test wbre used to find lhe sensitive antibiotics.120 SD rats were random divided into five groups,five different concentrations of Pseudomonas aeruginosa were injecked into the rats with the same volume.Six rats of each group were picked up for taking blood for culture at the time points of Oh,12h,24h,and 48h after narcotization.Finally,the oprⅠ gene of each blood samples were checked with FQ- PCR.72 rats were random divided into three groups,therapeutic group,treated group and control group.Pseudomonas aeruginosa with the concentration of 1×109 CFU/ml were injected into those rats.Sensitive antibiotics,insensitive antibiotics and 0.9% NaCl were given to the therapeutic,treated and control group rats respectively.Six rats of each group were picked up for taking blood for culture at the time point of Oh,12h,24h,and 48h after narcotized.Finally,the oprⅠ gent of each blood sample were checked with FQ-PCR.Results The blood culture were positive in each period of the concentrations 1×109 CFU/ml and 1×108 CFU/ml.Results of FQ-PCR showed that the copy number decreased with time going,all of which were positive.The blood culture were positive at the time points of Oh and 12h with the concentrations of 1×107 CFU/ml and 1×106 CFU/ml,were positive with concentration of 107 CFU/ml at the time point of 24h,but negative with concentration of 107 CFU/m at the time point of 48h,and negative with the concentration of 1×106 CFU/ml at the time points of 24h and 48h.The blood culture were negative in each period of the concentration of 1×105 CFU/ml,and the results of FQ-PCR were negative.The blood culture were positive in each period of both treated and control group,but negative in each period of therhpeutic group,all the results of FQ-PCR were positive.Conclusion The coincidence rate between the method of FQ-PCR and trgditional germicuhure were 100%.Though the sensitivity of FQ-PCR was not increased,the time needed by diagnosis was shorter After treated with effective antibiotic,fhe sensitivity of FQ-PER to diagnosis Pseudomonas aeruginosa septicemia was higher than that of traditional germicuhure,and the experiment time was shorter.Detected the changes of the oprⅠ gene copies number may be helpful to estimate the sensitivity of antibiotic.