Multiple-Antibiotic Resistance in Salmonella enterica Serovars Isolated in Iran Harboring Class 1 Integrons
Bahareh Rajaei
Department of Microbiology, Pasteur Institute of Iran, Tehran, Iran and Department of Stem Cells, Division of Nanobiomaterials and Tissue Engineering, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran.
Nahid Sepehri Rad
Department of Microbiology, Pasteur Institute of Iran, Tehran, Iran.
Farzad Badmasti
Department of Microbiology, Pasteur Institute of Iran, Tehran, Iran
Mohamad Reza Razavi
Department of Parasitology, Pasteur Institute of Iran, Tehran, Iran
Mohammad Reza Aghasadeghi
Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran.
Raheleh Saboohi
Department of Microbiology, Pasteur Institute of Iran, Tehran, Iran
Taraneh Rajaei
Department of Biotechnology, Pasteur Institute of Iran, Tehran, Iran.
Arfa Moshiri
Department of Microbiology, Pasteur Institute of Iran, Tehran, Iran. and Research Institute for Endocrine Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Seyed Davar Siadat *
Department of Microbiology, Pasteur Institute of Iran, Tehran, Iran and Department of Mycobacteriology and Lung Research, Pasteur Institute of Iran, Tehran, Iran.
*Author to whom correspondence should be addressed.
Abstract
Aims: This research was carried out to detect the content and distribution of class 1 integrons in multidrug resistant Salmonella isolates.
Materials and Methods: Eighty four clinical isolates of Salmonella serovars were subjected to molecular detection of class 1 integrons following the antimicrobial susceptibility test using disk diffusion method and MIC determination.
Results: Eleven isolates (13.1%) which were resistant to at least 4 groups of antimicrobial agents considered as MDR (multidrug resistant) Salmonella serovars. The intI1 gene and internal variable regions (IVRs) of class 1 integron were detected in 50 (59.5%) and 35 (70%) of Salmonella clinical isolates respectively. Analysis of the sequence data revealed four gene cassette arrays including the dhfr7 (0.8 kb), aadA1 (1kb), blaP1 (1.2 kb), dhfr1-aadA1 (1.6 kb) with eight IVR distribution patterns.
Conclusion: Detection of class 1 integron carrying gene cassettes which confer resistance to different classes of antibiotics such as aminoglycosides, ß-lactams and trimethoprim confirms that integron-mediated antimicrobial gene cassettes are prevalent in Salmonella serovars isolated in Iran.
Keywords: Class 1 integron, multidrug resistance, gene cassette array