Background & objectives: Drug resistance is one of the most problems in controlling microbial infections which assumes to be ever-increasing problem all through the world. Production of extended-spectrum &beta-lactamases enzyme (ESBLS) can cause a resistance to antibiotics of gram negative bacteria. The main purpose of this study was to determine antibiotic sensitivity patterns and SHV-1 genes frequency in collected urinary samples from hospitalized patients in Ardebil.

Methods: 400 isolated Enterobacteriaceae from urinary samples were recognized using an ordinary biochemical method. Antibiotic sensitivity test was conducted by Kirby and Bauer. The combined disk method was also utilized as a confirmatory test. The results were compared to clinical and laboratory standards institute (CLSI) standards. Finally, ESBL positive isolates were investigated by PCR method regarding the SHV-1 gene.

Results: From the total of 400 urinary isolates Enterobacteriaseae resistance to Ampicilin, Nalidixicacid, Co-trimoxazole, Cefotaxime, Ceftazidime, Ceftriaxone, Ciprofloxacin Ceftizoxime, Cefixime, Gentamycin, Imipenem were 82.5, 62.3, 67, 36, 49.5, 50.3, 52, 36, 41, 24.8 and 7.7 percents, respectively. 150 isolates (37.5%) were positive ESBL, and among all, 28 isolates (18.7%) contained SHV-1 gene.

Conclusion: According to obtained results from the study, regarding high percentage of resistance to antibiotics and high reduction of ESBL_S in bacteria from who suffered from urinary infections, taking some logical steps for prevention seems to be essential.