Study on the Resistance and Genotypes of ESBLs-producing Gram-negative Bacilli

OBJECTIVE:To study the detection rate, the genotypes and the drug resistance of (extended spectrum β-lactamase(ESBLs)-producing gram-negative bacilli(G-B) in our hospital. METHODS: 57 piperacillin-resistant G-B were isolated. ESBLs were detected by screening and confirmatory test. MIC values were determined by two-fold agar dilution method. β-lactamase enzyme activities were determined. PCR detection of blaSHV, blaTEM, blaCTX-M was performed. RESULTS: 24(42.1%) G-B produced ESBLs. The resistant rate of ESBLs-producing isolates to imipenem was lowest, which was 4.2%. 24 ESBLs-producing strains, 3 strains(12.5%) carried blaSHV genes, 6 strains(25%) carried blaTEM genes, and 9 strains(37.5%)carried blaCTX-M genes. CONCLUSIONS: Producing ESBLs is one of the main mechanisms of G-B resistant to β-lactam antibiotics. CTX-M-type ESBLs are epidemic in the hospital. Imipenen is the best choice for the treatment of the infections caused by ESBLs-producing G-B.