آنالیز اینتگرون‌ها و کاست‌های ژنی مربوطه در ایزوله‌های بالینی اشریشیاکلی

Background and Objective: Horizontal transfer of integrons is the most successful transfer of antimicrobial resistance genes and the emergence of multi-drug resistance strains. The aim of the present study was to investigate the prevalence of class I and II integrons and their gene cassette assortments and antibiotic resistance profile in Escherichia coli strains isolated from diarrheal and urine specimens. Materials and Methods: In this cross-sectional study 200 E. coli isolates were collected from the clinical urine and stool specimens. After identification of isolates by biochemical tests, the antibiotic susceptibility test (disk diffusion method) was done according to CLSI advice against 13 antibiotics. DNA extraction was performed and class 1 and 2 integrons and associated gene cassettes were determined using PCR method. Results: The highest resistance was found against erythromycin (96.5%) and %98.5 of isolates were susceptible to imipenem. Out of 200 isolates, class 1 integron was detected in 181 (90.5%) isolates and 78.5% of these isolates were positive for the gene cassettes. Also, class 2 integron was detected in 15 (7.5%) isolates and 2% of them were positive for the gene cassettes. Dihydrofolate reductase (dfrA) and aminoglycoside adenyl transferase (aad) gene cassettes were found most frequently in intI1 positive isolates. Conclusion: These results indicate that class 1 integrons are widespread among E. coli isolates. Therefore, appropriate surveillance and control measures are essential to prevent further spread of integron producing isolates. References 1- Goossensa H, Grabeind B. Prevalence and antimicrobial susceptibility data for extended- spectrum β- lactamas and AmpC- producing Enterobacteriaceaefrom the MYSTIC program in Europe and United States (1997- 2004). Diag Microbiol Infect Dis. 2005 53: 257-64. 2- Foxman B. Epidemiology of urinary tract infections: incidence, morbidity and economic costs. Dis Mon. 2003 49: 53-70. 3- Turner PJ. Extended-spectrum β-lactamases. Clin Infect Dis. 2005 41: 273-5. 4- Gillings MR. Integrons: past, present and future. Microbio Mol Biol Rev. 2014 78: 257-77. 5- Collis CM, Hall RM. Site-specific deletion and rearrangement of integron insert genes catalyzed by the integron DNA integrase. J Bacteriol. 1992 174: 1574-85. 6- Ravi A, Avershina E, Ludvigsen J, L’Abe e-Lund TM, Rudi K. Integrons in the intestinal microbiota as reservoirs for transmission of antibiotic resistance genes. Pathogens. 2014 3: 238-48. 7- Clinical and Laboratory Standards Institute. 2013. Performance standards for antimicrobial susceptibility testing 23th informational supplement (M100-S23) Vol. 31 No. 1. CLSI, Wayne, PA. 8- Mndelson G, Hait V, Ben-Israel J, Gronich D, Granot E, Raz R. Prevalence and risk factors of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in an Israeli long-term care facility. Eur J Clin Microbial infect Dis. 2005 24: 17-22. 9- Chen B, Zheng W, Yu Y, et al. Class 1 integrons, selected virulence genes, and antibiotic resistance in Escherichia coli isolates from the Minjiang river, Fujian province, China. Appl Environ Microbiol. 2011 77: 148-55. 10- Eftekhar F, Rastegar M, Golalipoor M, Mansour N. Detection of extended spectrum β-lactamases in urinary isolates of Klebsiella pneumoniae in relation to blaSHV, blaTEM and blaCTX-M gene carriage. Iran J Public Health. 2012 41: 127-132. 11- David L, Bonomo P, Bonomo R. Extended spectrum lactamases: a Clinical Update. Clinic Microb Rev. 2005 18: 657-686. 12- GhaznaviRad E, Ranjbaran M, et al. Molecular investigation of integrons in Escherichia Coli and Klebsiella Pneumoniae isolated from urinary tract Infections. J Mazand Univ Med Sci. 2013 23: 20-7. 13- Al-Charrakh H, Yousif Y, Al-Janabi S. Occurrence and detection of extended-spectrum β-lactamases in Klebsiella isolates in Hilla, Iraq. Afr J Biotechnol. 2011 10: 657-65. 14- Eslami G, Seyedjavadi S, Goudarzi H, Fallah F, Goudarzi M. Distribution of integrons among multidrug resistant E. coli and Klebsiella strains. Pejouhesh. 2010 34: 61-5. 15- Rijavec M, Starcic EM, Ambrozic AJ, et al. Prevalence of multidrug resistance and ran dom distribution of mobile genetic elements among uropathogenic Escherichia coli (UPEC) of the four major phylogenetic groups. Curr Microbiol. 2006 53: 158-62. 16- Rezaee MA, Langarizadeh N, Aghazadeh M. First report of class 1 and class 2 integrons in multidrug-resistant Klebsiella pneumoniae isolates from northwest Iran. Jpn J Infect Dis. 2012 65: 256-9. 17- Ibrahim N, Wajidi MF, Yusof MY. The integron prevalence of extended spectrum beta lactamase producing enterobacterial isolates in a Malaysian teaching hospital. J Trop Med. 2011 28: 668-71. 18- Yan H, Li L, Zong M. Occurrenece and characteristic of class I and class II integrons in clinical bacterial isolates from patientsin south China. J Health Sci. 2010 54: 442-50. 19- Bhattacharjee A, Sen M, Prakash P, Gaur A, Anupurba S, Nath G. Observation on integron carriage among clinical isolates of Klebsiella pneumoniae producing extended-spectrum β-lactamases. Indian J Med Microbiol. 2010 28: 207-10. 20- Brolund A, Sundqvist M, Kahlmeter G, Grape M. Molecular characterisation of trimethoprim resistance in Escherichia coli and Klebsiella pneumoniae during a two year intervention on trimethoprim use. PLoS One. 2010 5: e9233.