Different Features of Escherichia coli and Klebsiella pneumoniae in Children and Adults

Background: This study aimed to describe the association between age groups and antimicrobial susceptibility patterns, also integron presence in Escherichia coli and Klebsiella pneumoniae isolates from Tabriz, Iran. Methods: 140 isolates of E. coli and 150 isolates of K. pneumoniae, both comprising the same number of children and adult isolates were examined for susceptibility to 13 routine antibiotics. The integron existence in multidrug resistant (MDR) isolates was also determined using PCR-RFLP. Results: The significant age-related differences were observed in the resistant rates of K. pneumoniae toward cotrimoxazol, nalidixic acid, ciprofloxacin and norfloxacin. For E. coli, age-related differences in the resistance rates to tetracycline, chloramphenicol, ciprofloxacin and norfloxacin were significant. PCR-RFLP results revealed the presence of class 1 integron (intI1) in 24.5% and 19.2% of MDR E. coli in children and adults, respectively. In K. pneumoniae, 72.9% of children and 84% of adults isolates were positive for intI1. The prevalence of class 2 integrons was significantly associated with age group, in both E. coli and K. pneumoniae. No class 3 integrons were detected in this study. Conclusions: The resistance rates differ across age groups. Moreover, this study is the first that demonstrated age related differences in the integron presence, especially class 2 integrons, in E. coli and K. pneumoniae.