Molecular Detection of blaVEB-1 Beta-Lactamase Encoding Gene Among Extended Spectrum B-Lactamase Positive Wound Isolates of Pseudomonas aeruginosa

Abstract

Background: Pseudomonas aeruginosa is considered as a leading cause of nosocomial infections. Burn and wound infections are mainly caused by multidrug-resistant P. aeruginosa isolates. Drug resistance frequently occurs among nosocomial isolates and can usually resist a myriad of antibiotics such as novel beta-lactam antibiotics. Detection of multidrug-resistant isolates could assist better drug administration. Objectives: The aim of this study was to detect Extended Spectrum Beta-Lactamases (ESBL) positive wound isolates and the genes encoding bla(VEB-1) ESBL among wound isolates of P. aeruginosa. Materials and Methods: A total of 89 wound isolates of P. aeruginosa were collected from patients (47 (n = 42) were male and 53 (n = 47) were female) at six Iranian hospitals between years 2009 and 2011. Antibiotic susceptibility and phenotypic ESBL production tests were conducted. The combined disk was used to determine ESBLs production. The bla(VEB-1) gene was detected with the polymerase chain reaction (PCR). Results: The majority of the wound isolates were resistant to augmentin (90, n = 80) and cefpodoxime (87.6, n = 78). However, the majority was susceptible to imipenem and meropenem. Fifty-eight (42) wound isolates were ESBL positive. The antibiotic resistance amongst ESBL positive isolates was relatively higher than ESBL negative isolates. Twenty-three (40) ESBL-positive isolates amplified the bla(VEB-1) gene. Conclusions: More than behalf of the wound isolates were ESBL positive, and the presence of bla(VEB-1) was determined in less than half of these isolates. Fortunately, resistance to imipenem and meropenem was low.