Detection of extended-spectrum beta-lactamases and analysis of antibiotic resistance in clinical isolates of Klebsiella pneumoniae

AIM: To study the phenotype and genotype distribution of extended-spectrum beta-lactamases(ESBLs)-producing Klebsiella pneumoniae(K.pneumoniae)and its drug resistance.METHODS: Seventy-seven strains of K.pneumoniae were determined by 1999 NCCLs methods and the genotype of ESBLs was amplified by polymerase chain reaction(PCR).The antibiotic susceptibility of bacteria was determined by microdilution.RESULTS: In the 77 positive K.pneumoniae isolates of the initial screen test,45 strains(58.1%) were confirmed by cefotaxime and cefotaxime-clavulanic acid but only 27 strains were confirmed by ceftazidime and ceftazidime-clavulanic acid.PCR showed that TEM,SHV,CTX-M or OXA-type ESBLs in the clinical strains were 19,8,36,11 strains respectively.CONCLUSION: K.pneumoniae is one of the most common ESBLs-producing strains.The rates of ESBLs-producing K.pneumoniae significantly increase in recent years and CTX-M is most common genotype.Some strains carry two or more genotypes.Imipenem is the most susceptible antibiotic.