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-1) gene was 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 but there has been a rather high prevalence of it.