فهرست نشریات علمی دسترسی آزاد ایران

Background: Most urinary tract infections (UTIs) are caused by Escherichia coli (E. coli) species. Due to infections outbreaks of E. coli strains with multiple mechanisms of resistance to β-lactam antibiotics, the sensitivity of confirmatory tests to detect the extended spectrum β-lactamases (ESBLs) have decreased. Objectives: The current study aimed to introduce a modified method to detect ESBLs in Gram-negative bacilli. Methods: Totally, 86 clinical isolates of E. coli resistant to extended-spectrum cephalosporins were collected from patients with UTIs in Kerman, Iran. The susceptibility to antibiotics was determined by disk diffusion method. ESBLs producing isolates were identified by combination double disk synergy test (CDDST) and β-lactamase disk test. The β-lactamase genes including bla TEM , bla SHV , bla CTX-M , bla OXA-1 and bla PER were detected by polymerase chain reaction (PCR) method and sequenced. Results: All of the isolates were multidrug-resistant (MDR). In the current study 88% and 97.6% of the isolates were considered as ESBLs producing by CDDST and β-lactamase disk test, respectively. At least 92% of the isolates were positive for one of the bla CTX-M , bla TEM , bla OXA-1 and bla SHV genes. The bla CTX-M, bla TEM, bla OXA-1 and bla SHV genes were detected in 74.4%, 61.6%, 14% and 2.3% of the isolates, respectively. Conclusions: The β-lactamase disk test is appropriately sensitive to detect ESBLs in MDR isolates of E. coli .