بررسي ميزان شيوع ژن‌هاي tetA و اينتگرون كلاس يك در باكتري‌هاي اشريشياكلي مقاوم به تتراسايكلين جداسازي شده از ضايعات بيماري كلي باسيلوز طيور

Survey of prevalence of tet(A) and class 1 Integron genes in tetracycline-resistant Escherichia coli isolated from lesions of colibacillosis

از ﻣﺪتﻫـﺎ ﻗﺒـﻞ آﻧﺘـﯽﺑﯿﻮﺗﯿـﮏﻫـﺎ اوﻟـﯿﻦ ﺧـﻂ دﻓـﺎﻋﯽ ﺑـﺮاي ﺟﻠـﻮﮔﯿﺮي از ﻋﻔﻮﻧـﺖ اﺷﺮﯾﺸـﯿﺎﮐﻠﯽ ﺑﻮدﻧـﺪ، اﻣـﺎ از آﻧﺠـﺎ ﮐـﻪ ﺑﺎﮐﺘﺮيﻫـﺎ ﺑـﻪﻃـﻮر ﻓﺰاﯾﻨـﺪهاي در ﺑﺮاﺑـﺮ درﻣـﺎن ﻣﻘـﺎوم ﺷـﺪهاﻧـﺪ، ﻗـﺪرت ﺧـﻮد را از دﺳـﺖ دادهاﻧـﺪ. ﺗﺤﻘﯿـﻖ ﺣﺎﺿـﺮ ﺑـﺎ ﻫـﺪف ﺑﺮرﺳــﯽ ﻣﻘﺎوﻣــﺖ ﺑــﻪ ﺗﺘﺮاﺳــﺎﯾﮑﻠﯿﻦﻫﺎ و ﺷــﯿﻮع ژنﻫــﺎي ﻣﻘﺎوﻣــﺖ tetA و اﯾﻨﺘﮕــﺮون ﮐــﻼس ﯾــﮏ در اﺷﺮﯾﺸــﯿﺎﮐﻠﯽ ﺟــﺪا ﺷــﺪه از ﺟﻮﺟﻪﻫـﺎي ﮔﻮﺷـﺘﯽ ﻣﺒـﺘﻼ ﺑـﻪ ﮐﻠـﯽﺑﺎﺳـﯿﻠﻮز اﻧﺠـﺎم ﺷـﺪ. ﺑـﺎ اﻧﺠـﺎم آزﻣـﺎﯾﺶ آﻧﺘﯽﺑﯿـﻮﮔﺮام در اﯾـﻦ ﻣﻄﺎﻟﻌـﻪ 96/6 درﺻـﺪ از ﺟﺪاﯾــﻪﻫﺎي اﺷﺮﯾﺸــﯿﺎﮐﻠﯽ ﻣﻘــﺎوم ﺑــﻪ ﯾــﮏ ﯾــﺎ ﻫــﺮ دو آﻧﺘﯽﺑﯿﻮﺗﯿــﮏ داﮐﺴــﯽ ﺳــﺎﯾﮑﻠﯿﻦ و ﺗﺘﺮاﺳــﺎﯾﮑﻠﯿﻦ ﺑﻮدﻧــﺪ. ﻧﺘــﺎﯾﺞ آزﻣــﺎﯾﺶ ﻧﺸــﺎن داد 98/2 درﺻــﺪ از ﺑﺎﮐﺘﺮيﻫــﺎي اﺷﺮﯾﺸــﯿﺎﮐﻠﯽ ﻣﻘــﺎوم ﺑــﻪ ﺗﺘﺮاﺳــﺎﯾﮑﻠﯿﻦ ﺟﺪاﺳــﺎزي ﺷــﺪه از ﺿــﺎﯾﻌﺎت ﺑﯿﻤــﺎري ﮐﻠﯽﺑﺎﺳــﯿﻠﻮز ﺣﺎﻣــﻞ tetA ﻣﯽﺑﺎﺷــﻨﺪ. ﻣﯿــﺰان ﺷــﯿﻮع ژن اﯾﻨﺘﮕــﺮون ﮐــﻼس ﯾــﮏ 98/2 درﺻــﺪ ﻣﯽﺑﺎﺷــﺪ. ﻫﻤﭽﻨــﯿﻦ 96/5 درﺻــﺪ از ﺟﺪاﯾــﻪﻫﺎي اﯾــﻦ ﺑــﺎﮐﺘﺮي ﺣﺎﻣــﻞ ﻫــﺮ دو ژن اﯾﻨﺘﮕــﺮون ﮐــﻼس ﯾــﮏ و tetA ﻣﯽﺑﺎﺷــﻨﺪ. ﺑــﺎ در ﻧﻈــﺮ ﮔــﺮﻓﺘﻦ ﻧﺘــﺎﯾﺞ، ﺷــﯿﻮع دو ژن tetA و اﯾﻨﺘﮕــﺮون ﮐــﻼس ﯾــﮏ در اﯾــﻦ ﺗﺤﻘﯿــﻖ ﻧﺴــﺒﺖ ﺑــﻪ ﺳــﺎﯾﺮ ﭘﮋوﻫﺶﻫــﺎي اﻧﺠــﺎم ﮔﺮﻓﺘــﻪ ﺑــﻪﻃﻮر ﻗﺎﺑــﻞ ﻣﻼﺣﻈﻪاي ﺑﯿﺸﺘﺮ اﺳـﺖ ﮐـﻪ اﯾـﻦ ﺗﻔـﺎوت ﻣﯽﺗﻮاﻧـﺪ ﺑﯿـﺎﻧﮕﺮ ﻣﻘﺎوﻣـﺖ آﻧﺘﯽﺑﯿـﻮﺗﯿﮑﯽ زﯾـﺎد در ﻣﺮﻏـﺪاريﻫﺎي اﯾـﻦ ﻣﻨﻄﻘـﻪ ﺑﺎﺷـﺪ ﮐـﻪ ﺑـﺮ ﻟـﺰوم اﺳـﺘﻔﺎده ﻣﺤﺘﺎﻃﺎﻧــﻪ از ﺗﺘﺮاﺳـﺎﯾﮑﻠﯿﻦﻫﺎ در ﺗﻮﻟﯿـﺪ ﻃﯿـﻮر ﺑـﺮاي ﮐــﺎﻫﺶ ﺷـﯿﻮع اﺷﺮﯾﺸـﯿﺎﮐﻠﯽ ﻣﻘـﺎوم در ﺑﺮاﺑـﺮ اﯾــﻦ آﻧﺘﯽﺑﯿﻮﺗﯿﮏﻫﺎ ﺗﺄﮐﯿﺪ ﻣﯽﮐﻨﺪ.

Antibiotics have long been the first line of defense against Escherichia coli infection, but they have lost their potency as the bacteria become increasingly resistant to treatment. The aim of this study was to evaluate the resistance to tetracyclines and the prevalence of tetA and integron class I resistance genes in E. coli isolated from broilers with colibacillosis. In this study, 96.6 % of Escherichia coli isolates resistant to one or both tetracycline antibiotics were studied. Experimental results showed that 98.2 % of tetracycline-resistant Escherichia coli bacteria isolated from lesions of colibacillosis carry tetA. The prevalence of class I integron gene was 98.2%. Also, 96.5% of the isolates of this bacterium carried both genes. Considering the results, the prevalence of tetA and integron class 1 genes in this study was significantly higher than other studies. This difference could indicate high antibiotic resistance in poultry farms in this region which emphasizes the need for cautious use of tetracyclines in poultry production to reduce the prevalence of E. coli resistant to these antibiotics.