Antimicrobial Resistance Patterns and Molecular Characterization of Class 1 and Class 2 Integron , Integrase Genes in Klebsiella pneumoniae Isolated from Human and Veterinary Clinical Samples

This study aimed to isolate, identify, and compare Klebsiella pneumoniae from cow milk and human urine samples, and to evaluate their antimicrobial resistance patterns and integron gene distribution. A total of 200 samples were analyzed, including 100 cow milk and 100 human urine samples. Klebsiella spp. were isolated using selective and differential media. On MacConkey and EMB agar, 25% of milk isolates and 30% of urine isolates were obtained. On Klebsiella Chrome agar, 48% of milk isolates and 46.66% of urine isolates were confirmed as K. pneumoniae based on characteristic blue mucoid colonies.Molecular confirmation using PCR targeting the rpoB gene verified all selected isolates (100%) as K. pneumoniae, producing a 108 bp band. Antimicrobial susceptibility testing (Kirby-Bauer method) showed variable resistance patterns against five antibiotic classes. Similar resistance was observed in both sources against penicillins, tetracyclines, and aminoglycosides, while urine isolates showed higher resistance to carbapenems and ciprofloxacin. All isolates were classified as multidrug-resistant (MDR), showing resistance to more than three antibiotic classes.PCR detection of integron genes revealed that class 1 integron (int1) was present in 100% of isolates, while class 2 integron (int2) was detected in 75% of milk isolates and 33.33% of urine isolates.In conclusion, the study highlights the widespread occurrence of multidrug-resistant K. pneumoniae in both animal and human sources, with integrons playing a significant role in the dissemination of antimicrobial resistance.