Phenotype and Genotype of Nosocomial Infection Strains of Klebsiella pneumoniae

OBJECTIVE To investigate the prevalence,antibiotic resistance and genotype of the extended-spectrum β-lactamases(ESBLs)-producing clinical isolates of Klebsiella pneumoniae.METHODS A total of 104 isolates of K.pneumoniae were examined for the ESBLs production and the susceptibilities of the bacteria to 15 antimicrobial agents.PCR was performed to detect the genes encoding the ESBLs belonging to SHV and TEM families as well as CTX-M-1 and CTX-M-9 groups.RESULTS The ESBLs-producers of K.pneumoniae were 54.0% in the total of 104 isolates.Almost all of the ESBLs-producing isolates were resistant to the antibiotics commonly used,and only remained susceptible to carbapenems and the combination of cefoperazone with sulbactam.The genes of SHV,CTX-M-1 and TEM groups were detected in the ESBLs-producing isolates by 64.3%,46.4%,and 32.1%,respectively,and 35.7% and 8.9% of ESBLs-producing K.pneumoniae strains carried two and three genes.CONCLUSIONS The clinical isolates of K.pneumoniae in Tianjin Nankai Hospital are shown a high rate of ESBLs-producing and antibiotic resistance.SHV and CTX-M-1 groups of ESBLs are the dominant genotypes in the isolates of ESBLs-producing K.pneumoniae.