Antibiotic resistance analysis and CTX-M enzyme detection of ESBLs-producing Escherichia coli and Klebsiella pneumoniae

Objective To investigate genotypes of CTX-M and resistance phenotype of ESBLs-producing Escherichia coli and Klebsiella pneumoniae isolated from Beijing Ditan Hospital.Methods The MICs of 20 antibiotics against 21 ESBLs-producing germs were determined by microquality and quantity analysis.CTX-M-type β-lactamase encoding genes were amplified by PCR.The nucleotide sequence of CTX-M encoding genes were characterized with automatic sequencer.Results Resistance to most β-lactams,fluoroquinolones and aminoglycosides antibiotics were found in 21 ESBLs-producing strains.No strain was found to be resistant to imipenem.Ten strains were investigated to produce CTX-M-type ESBLs,including CTX-M-14 (7 strains) and CTX-M-3 (2 strains),CTX-M-9 (1 strain).Conclusions Most of ESBLs-producing strains were multi-drug resistant and there were prevalence of CTX-M-type β-lactamases in Escherichia coli and Klebsiella pneumoniae isolated in Beijing Ditan Hospital from August in 2006 to July in 2007.Main genotypes of CTX-M of ESBLs-producing bacteria were CTX-M-14 and CTX-M-3.