Study on the Resistance of Klebsiella Pneumoniae Induced by Ciprofloxacin and Sparfloxacin in Vitro / 中国药房

ABSTRACT

OBJECTIVE:To study the difference between the hydrophilic and hydrophobic fluoroquinolones(FQNLs)in?ducing resistant Klebsiella pneumoniae(Kpn)in vitro.METHODS:Hydrophilic ciprofloxacin(CIP)and hydrophobic sparfloxacin(SPFX)were used to induce FQNLs resistant mutants from a clinical susceptible isolate Kpn909with stepwise selection method,respectively,The susceptivity of bacteria to was determined by the standard method of two fold agar dilu?tion.RESULTS:The resistance of Kpn909to FQNLs was raised up gradually as FQNLs'concentration increased;Minimum inhibitory concentrations(MICs)of Kpn9098Selected by CIP at2?MIC(0.5mg/L)were16～32times higher than that of Kpn909,and showed resistant to ofloxacin(OFX),lomefloxacin(LMFX)and enofloxacin(ENX)with a MIC of8mg/L,16mg/L and8mg/L.Otherwise,SPFX-selected Kpn with a similar resistant level occurred at the concentration of8?MIC(1mg/L).The maximal selecting concentration of CIP and SPFX were128mg/L and64mg/L,and MIC of5FQNLs to the resistant mutants obtained at which were≥256mg/L and32～128mg/L,respectively.CONCLUSION:Both hydrophilic CIP and hydrophobic SPFX could induce Kpn the cross resistance to others FQNLs,but hydrophobic FQNLs may be superior to hydrophilic FQNLs to delay the resistance occurrence in Kpn.