PCR Detection of VIM-1, VIM-2 and IMP-1 Metalo-beta-lactamases in Clinically Multi Drug Resistant P. aeruginosa Isolated in Tehran, Iran

Abstract

All qnr and aac(6’)-Ib-cr positive isolates were typed by RAPD. Results: Antibiotic resistant Enterobacteriaceae were cultured from 25/27 (93%) adults, 68/77 (88%) children and 42/100 (42%) neonates. A total of 60, 252 and 97 strains were isolated in each group respectively. ESBL-positive strains were present amongst 67/334 (20%) E. coli, 18/43 (42%) K. pneumoniae and 9/32 (28%) other Enterobacteriaceae. Out of 409 strains of Enterobacteriaceae, 309 (76%) strains were resistant to nalidixic acid, 263 (64%) to gentamicin, 19 (5%) to amikacin, 43 (11%) to piperacillin-tazobactam. qnrA, qnrB, qnrS and aac(6′)-Ib-cr genes were present in 3 (0.7%), 3 (0.7%), 47 (11.5%), and 12 (2.9%) isolates, respectively, which were shown to be unique by RAPD. The MIC50 to ciprofloxacin of qnr and aac(6′)-Ib-cr positive isolates was >0.75mg/l, the MIC90 >32mg/l. Conclusion: The carriage rate of drug-resistant Enterobacteriaceae in healthy people in Hochiminh City is extremely high. Moreover, genes encoding transferable quinolones, in particular qnrS, are highly prevalent in these strains.