Coexistence of integrons class 1 and 2 with emergence of class 3 among Proteus mirabilis clinical isolates from Alexandria, Egypt

Document Type : Original Article


Department of Microbiology, Medical Research Institute, Alexandria University, Alexandria, Egypt.


Background:  The aim of the study was to investigate the antimicrobial resistance and prevalence of integrons in 100 Proteus mirabilis (P. mirabilis) clinical isolates from Egypt. Methods: Vitek-2 Compact system was used for bacterial identification, and antimicrobial susceptibility was performed using the Kirby-Bauer method. Primers for the integrase gene (intI1, intI2, and intI3) were used to screen for integrons using polymerase chain reaction (PCR). Additionally, the variable regions of class 1 and 2 integrons were amplified and sequenced. Results:Urine was the most common specimen (75%) followed by pus (21%). The highest antibiotic resistance among isolates was to ampicillin (61%), followed by trimethoprim-sulfamethoxazole (50%), with 34% of strains being multidrug-resistant (MDR). Class 1 was the most prevalent integron detected in 80%, with 8 different gene cassettes, the most prevalent being (AadA and dfrA17).  Class 2 was detected in 66% of isolates, and class 3 integron in 21% of isolates. To the best of our knowledge, this is the first report of integron 3 in P. mirabilis clinical isolates. Conclusions: In summary, antimicrobial resistance and integrons are prevalent among P. mirabilis isolates in Egypt which poses a great threat to the treatment of MDR bacterial infections therefore, special measures should be taken to prevent spread of integrons and associated resistance genes.


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