title: Antimicrobial Resistance Patterns and Prevalence of blaPER-1 and blaVEB-1 Genes Among ESBL-producing Pseudomonas aeruginosa Isolates in West of Iran.
abstract: BACKGROUND
  Pseudomonas aeruginosa is a leading cause of nosocomial infections worldwide. Resistance of P. aeruginosa strains to the broad-spectrum cephalosporins may be caused by extended-spectrum β-lactamases (ESBLs).
  
  
  OBJECTIVE
  The aim of this study was to determine the antimicrobial resistance patterns and prevalence of PER-1 and VEB-1 type genes among ESBL producing strains of P. aeruginosa.
  
  
  METHODS
  A total of 106 P. aeruginosa isolates were collected from two university hospitals in Hamadan, Iran, during a7-month study (2009). The antimicrobial susceptibility of isolates was determined by disc diffusion method and interpreted according to the clinical and laboratory standards institute (CLSI) recommendations. Production of ESBL was determined by combined disk test and presence of PER-1 and VEB-1 type ESBL genes was identified by PCR.
  
  
  RESULTS
  The resistance against broad-spectrum cephalosporins and monobactames were: cefepime (97%), cefotaxime (92.5%) ceftazidime (51%), and aztreonam (27%). Ciprofloxacin (91.5%), imipenem (84.9%) and meropenem (82.1%) were the most effective anti-pseudomonas agents in this study. The results revealed that 88.7% of the isolates were multidrug resistant, 58.25% of those were ESBL positive. Sixteen (26.6%), 9 (15%) and 3 (5%) strains among ESBL-producing strains contained blaPER-1, blaVEB and blaPER-1-blaVEB, respectively.
  
  
  CONCLUSIONS
  This study highlighted the need to establish antimicrobial resistance surveillance networks for P. aeruginosa to determine the appropriate empirical treatment regimens. The high prevalence of multidrug resistance and production of ESBLs in P. aeruginosa isolates conﬁrms the necessity of protocols considering these issues in the hospitals.
authors.affiliation: Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, IR Iran.
authors.forename: Mohammad Yousef
authors.initials: MY
authors.lastname: Alikhani
authors.affiliation: Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, IR Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Karimi Tabar
authors.affiliation: Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, IR Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Mihani
authors.affiliation: Department of Microbiology, School of Medicine, Alborz University of Medical Sciences, Alborz, IR Iran.
authors.forename: Enayat
authors.initials: E
authors.lastname: Kalantar
authors.affiliation: Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, IR Iran.
authors.forename: Pegman
authors.initials: P
authors.lastname: Karami
authors.affiliation: Tuberculosis and Lung Research Center, Tabriz University of Medical Sciences, Tabriz, IR Iran.
authors.forename: Mahnaz
authors.initials: M
authors.lastname: Sadeghi
authors.affiliation: Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, IR Iran.
authors.forename: Shiva
authors.initials: S
authors.lastname: Ahdi Khosroshahi
authors.affiliation: Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, IR Iran.
authors.forename: Safar
authors.initials: S
authors.lastname: Farajnia
keywords: Antimicrobial Drug Resistance; Beta-lactamase; Pseudomonas aeruginosa