RESUMEN
Background:Resistance to antibiotics due to extended \ufffd?spectrum \ufffd?Lactamase (ESBL) which increased quickly, made treatment much more difficult. However, this matter was not enough to be concerned in our country. Objectives: To investigate the prevalence of ESBL producing among clinical isolates of E.coli, K.pneumoniae and Enterobacter spp and the classification of ESBLs gene by PCR. Subjects and method: 663 strains, including 248 E.coli, 393 K.pneumoniae, 22 Enterobacter spp, isolated from patients in Viet Tiep hospital (Hai Phong), Bach Mai and Pediatric hospital (Ha Noi). ESBLs were detected using modified double \ufffd?disc method. The classification of ESBLs producing strains was implemented by PCR. Results:the percentage of ESBL producing in E.coli, K.pneumoniae and Enterobacter spp is 20.2; 18.3 and 36.4%, respectively. The ESBLs producing strains were co \ufffd?resistant to most of the tested antibiotics. These strains were prevalent in intensive care units (sputum or respiratory fluid samples). TEM, SHV, CTX \ufffd?M, OXA were 87.7; 62.3; 24.6 and 12.3%, respectively. They were detected alone or in combination in the same strain. Conclusion: The rate of ESBLs producing strains is high. ESBLs were marker for multi \ufffd?drug resistance. TEM and SHV type ESBLs are most prevalent in the tested strains.