Tetracycline Resistance Associated with tet Genes or Integrons among Enterobacter cloacae Strains Isolated from Patients with Urinary Tract Infections

Background: This study aimed to evaluate the prevalence of tet genes and Class I and 2 integrons in Enterobacter cloacae strains isolated from patients with urinary tract infections (UTIs). Materials & Method: A total of 50 E. cloacae isolates were collected. Antimicrobial susceptibility pattern and tetracycline MIC were determined. The presence of tet genes (tetA, tetB, tetC, tetD) and Class 1 and 2 integrons and the content of Class 1 integron were determined. Findings: Tetracycline MIC pattern classified 36 % of the E. cloacae isolates as resistant. The most common tet gene was tetC (22%), followed by tetD, tetA, and tetB. Class 1 integron was detected in 64% of the isolates. Class 1 integron content analysis showed two variable gene cassettes (aadA1 and aadA5/dfrA17 genes). The frequency of aadA5/dfrA17 was 18.75%, which was more common than aadA1 gene (6.25%). Conclusion: The most important genetic markers for tetracycline resistance in E. cloacae isolates were tetC and Class 1 integron. Harboring Class 1 integron and resistance to streptomycin and ciprofloxacin were significantly correlated.