Resistance Pattern of Tetracycline in Escherichia coli Isolates from Hospitalized Patients in Gonbad Kavus

Escherichia coli is the most common cause of urinary tract infection. Unfortunately, excessive use of antibiotics has led to the release of resistant pathogens and enhancement of resistance genes.The aim of this study was to evaluate the resistance pattern of tetracycline in uropathogenic E. coli strains isolated from patients hospitalized in different wards of hospitals in Gonbad e kavus and environs.

In this study, 310 urine samples were collected from hospitalized patients. After performing diagnostic tests, antibiotic susceptibility test was performed using the disk diffusion method (Kirby-Baer method) and broth microdilution. Then they were identified by PCR and specific primers of tetA and tetB resistance genes.

Of 193 isolates, 33.2% showed resistance to tetracycline, and the highest sensitivity was observed to cefepime (81%). Determination of minimum inhibitory concentration of tetracycline showed that 48% of strains showed MIC≤4 μg/mL and the highest growth rates were observed at MIC=2 μg/mL. Of the 64 isolates, 28 isolates (43.8%) had the tetA gene, and 31 isolates (48.4%) had the tetB gene, while only 1 isolate (1.6%) shared both genes.

The results showed that resistance to tetracycline is relatively common in E. coli isolates, but the frequency of tetA and tetB resistance genes are approximately the same in the strains isolated from hospitalized patients.