prevalence of per-1- type extended-spectrum beta-lactamaes in clinical strains of pseudomonas aeruginosa isolated from tabriz, iran

objective(s) the aim of this study was to investigate the presence of per-1-type esbls in drug resistant pseudomonas aeruginosa isolates. materials and methods during one-year period (2008-2009), following isolation and identification of 56 p. aeruginosa, the e-test method was performed for determination of minimal inhibitory concentration of ceftazidim. the isolates that they had mic≥16 µg/ml against ceftazidim were used for determination of esbl-producing by combined disk test (cdt) and double disk synergy test (ddst) methods. bla per-1genewas investigated by pcr.p. aeruginosa koas was used as positive control. results twenty-nine (51.78%) out of fifty six isolates had mic≥16 µg/ml to ceftazidime, twenty two (75.86%) of them were esbl producers. some isolates (27.5%) contained bla per-1 gene. conclusion per-1-type esbls producing p.aeruginosa has not been reported previously in tabriz but there has been a rather high prevalence of it.