Prevalence of integrons and Antimicrobial Resistance Genes Among Clinical Isolates of Enterobacter spp. From Hospitals of Tehran

were identified by using API 20E system. The existence of integron classes was investigated by PCR assay through the amplification of integrase genes. Then, antibacterial susceptibility and confirmation of ESBL phenotype was determined. Then, the bla groups, bla TEM , bla SHV , bla CTX-M-1 and aminoglycoside modifying enzymes genes were identified by PCR with specific primers. Results: The prevalence of Enterobacter species were E. cloacae (78.2 %), E. aerogenes (13.6 %) and E. sakazakii (8.2%). They were from different clinical sources. Forty five of Enterobacter isolates have integron but there was not detected class 3 of integrons. All isolates with integron were susceptible to imipenem. Ten isolates of Enterobacter with integron showed ESBL phenotype. The frequency of bla TEM , bla SHV and bla CTX-M-1 genes are 20%, 0% and 15.6%, respectively. The frequency of genes encoding ANT (2˝)-Ia, APH (3΄)-Ia, AAC (6΄)-Ib and AAC (3)-IIa were 11.1%, 13.3%, 13.3 % and 20 %, respectively. Conclusions: The high prevalence of integron-positive isolates in our MDR Enterobacter isolates indicates that these mobile genetic elements are common among different Enterobacter spp. and associate with reduced susceptibility to the first-line antimicrobial drugs. This so highlight the continued monitoring of drug resistance in clinical settings.