Distribution of Extended-Spectrum β-Lactamases in Clinical Isolates of Enterobacteriaceae in Vietnam

Abstract

Among 730 Escherichia coli , 438 Klebsiella pneumoniae , and 141 Proteus mirabilis isolates obtained between September 2000 and September 2001 in seven hospitals in Ho Chi Minh City, Vietnam, 26.6% were resistant to ceftazidime, 30% were resistant to cefotaxime, 31.5% were resistant to ceftriaxone, 15.9% were resistant to cefoperazone, and 6% were resistant to cefepime. Resistance to imipenem was found in 5.6% of the isolates. In 55 strains producing extended-spectrum β-lactamases (32 E. coli isolates, 13 K. pneumoniae isolates, and 10 P. mirabilis isolates), structural genes for VEB-1 (25.5%), CTX-M (25.5%), SHV (38.1%), and TEM (76.3%) enzymes were detected alone or in combination. Sequencing of the PCR products obtained from the K. pneumoniae isolates revealed the presence of bla _VEB-1 , bla _CTX-M-14 , bla _CTX-M-17 , bla _SHV-2 , and bla _TEM-1 . Molecular typing of the strains with a similar resistance phenotype to broad-spectrum cephalosporins indicated polyclonal spread. IS Ecp1 was presumably responsible for dissemination of the bla _CTX-M-like gene.