Detection of Different Types of Class 1, 2 and 3 Integrons among Pseudomonas aeruginosa Isolates from Raw Milks

Background: Pseudomonas aeruginosa is a leading cause of hospital-acquired infections that causes severe diseases in immuno-compromised individuals. integrons have a major role in multidrug resistanct, diversity, evolution and recombination strains. Various animals may act as the reservoir for bacterial humans pathogens. This study is aimed to evaluate the frequency of class 1, 2 and 3 integrons in P. aeruginosa isolates detected in raw milks. Methods: Identification of isolates were confirmed with morphology, Gram staining and biochemical tests. Drug resistance to various antibiotics was investigated using agar disk diffusion method. After DNA extraction of the isolates, they were subjected to a polymerase chain reaction for detection of class 1, 2 and 3 integrons. Results: In this study, 60 P. aeruginosa isolates were isolated from raw milk samples. The isolates showed resistance to amikacin (100%), ampicillin (100%), gentamicin (86.6%), cefotaxime (10%), ciprofloxacin (6.6%) and ceftazidime (3.3%). PCR analysis revealed the presence of intI-1in 49(81.6%), intI-2 in 9(15%), and intI-3 in 31(51.6%) isolates. Furthermore, class 1 and class 2 integrons were detected in 8(13.3%). In place, class 1 and class 3 integrons were observed in 26(43.3%) and class 2 and class 3 integrons in 6(10%) isolates. Conclusion: Ciprofloxacin and ceftazidime were the most effective antibiotics against P. aeruginosai isolates in this study. The distribution of different classes of integrons in this study was high and it sheds light on the importance of regulations on the antibiotic uses.