Genetic Analysis of Integrons among Methicillin-resistant and Susceptible Staphylococcus aureus Isolated from Nosocomial Infections

Integrons are mobile genetic elements that play an important role in dissemination of antibiotic resistance genes. The aim of present study is to determine the antibiotic resistance profile, frequency of integrons genes (class 1, 2, 3) and compare it between MRSA and MSSA isolates from clinical infections.
50 MRSA and 50 MSSA isolates from March to September 2015 were isolated from infection site of hospitalized patients referred to Valiasr hospital Arak, Iran were subjected to this study. All isolates were tested for susceptibility to antibiotics using disk diffusion method. Then, the mecA gene was studied to validate resistance. The frequency of integrons (class 1, 2, 3) and the variable region genes like qacEDescription: Delta1 and sul1 in isolates were determined by PCR method.
The highest antibiotic resistances rate in isolates was found for clindamycin. All of the isolates were susceptibel to vancomycin. 80% of MRSA and 40% of the MSSA isolates carried class 1 integrons, whereas class 2 integron were found in 12 % and 4% of MRSA and MSSA isolates, respectively. Also, all isolates that were class 1 integron gene positive contain qacEDescription: Delta1 and sul1 genes. Class 3 integrons were not found.
The high frequency of class 1 integron in MRSA and MSSA isolates associated with high rate of antibiotic resistance indicating that may be integrons play an important role facilitating the spread of antimicrobial resistance in this region. Clinical doctors and infection control committee should take this issue seriously.