A Study On The Active Efflux Mechanism In Enterococcus And The Relativity Of EmeA Gene With Enterococcus Resistance

Objective: To determine the susceptibility of fluoroquinolones againstEnterococcus .To explore the effect to the active efflux mechanism in Enterococcus and to detect the distribution and expression of active efflux pump gene emeA for the guidance of rational use of antibiotics and effective surveillance of nosocomial infections.Methods: 112 strains of the derived-infection Enterecocci were isolated, culturedand detected according to Clinical Test Operating Instruction of China. The Minimum inhibitory concentration (MIC) of three antibiotics agents of FQs combined 20mg/L reserpine against 112 strains of Enterecocci was determined by two-fold agar dilution method simultaneously. The distribution of emeA in clinical strains of Enterococcus was determined by polymerase chain reaction(PCR), and the level of mRNA expressions of emeA by RT-PCR. One of the PCR products was purified and sent to be sequenced and analyzed the sequence with Blast software. The correlation of emeA gene and resistance was studied.Results: Among the 112 clinical isolates, there were 82 (73.2%) strains ofEnterococcus faecalis, 28 (25.0%) strains of Enterococcus faecium, 2 (1.8%) of other enterococcus species. The enterococcus isolates rates from urine, secretion with pus, sputum, and others were 58.9%, 11.6%, 24.1%, and 5.4% respectively.In decreasing order, the relative activities(MIC5o,MIC9o) of 3 fluoroquinolones against Enterococcus were as follows: gatifloxacin (1mg/L,4mg/L respectively) ,...