ﺷﻨﺎﺳﺎﯾﯽ ژن ﻋﺎﻣﻞ ﺗﻮرم و ﻣﺮگ ﺳﻠﻮل (cdt) در سويه هاي اشريشيا كلي جداشده از كلي باسيلوز طيور

Detection of Cytolethal distending toxin (cdt) Genes in Escherichia coli Isolates from Poultry Colibacillosis

ﻋﺎﻣﻞ ﺗﻮرم و ﻣﺮگ ﺳﻠﻮل( cdt) ﺗﻮﮐﺴﯿﻨﯽ اﺳﺖ ﮐﻪ ﺣﻀﻮر آن در ﺑﺴﯿﺎري از ﺑﺎﮐﺘﺮﯾﻬﺎي ﺑﯿﻤﺎرﯾﺰاي ﮔﺮم ﻣﻨﻔﯽ ﻧﻈﯿﺮ اﺷﺮﯾﺸﯿﺎ ﮐﻠﯽ ، اﺷﺮﯾﺸﯿﺎ آﻟﺒﺮﺗﯽ، ﮔﻮﻧﻪ ﻫﺎي ﻣﺨﺘﻠﻒ ﮐﻤﭙﯿﻠﻮﺑﺎﮐﺘﺮ و ﺷﯿﮕﻼ ﮔﺰارش ﺷﺪه اﺳﺖ. ﺳﻮﯾﻪ ﻫﺎي اﺷﺮﯾﺸﯿﺎ ﮐﻠﯽ ﺗﻮﻟﯿﺪ ﮐﻨﻨﺪه اﯾﻦ ﺗﻮﮐﺴﯿﻦ از ﺑﯿﻤﺎران ﻣﺒﺘﻼ ﺑﻪﮔﺎﺳﺘﺮواﻧﺘﺮﯾﺖ، ﻋﻔﻮﻧﺖ ﻫﺎي دﺳﺘﮕﺎه ادراري و ﺳﭙﺘﯽ ﺳﻤﯽ در اﻧﺴﺎن ﺟﺪاﺳﺎزي ﺷﺪه اﺳﺖ. ﻣﻨﺒﻊ ﻋﻔﻮﻧﺖ در اﻧﺴﺎن ﺗﺎﮐﻨﻮن ﻧﺎﺷﻨﺎﺧﺘﻪ ﻣﺎﻧﺪه اﺳﺖ. از آﻧﺠﺎﯾﯿﮑﻪ ﮔﻮﺷﺖ و ﻓﺮآورده ﻫﺎي آن، ﯾﮑﯽ از ﻣﻨﺎﺑﻊ ﻣﻬﻢ ﻋﻔﻮﻧﺖ ﻫﺎي ﻧﺎﺷﯽ از ﻣﻮاد ﻏﺬاﯾﯽ ﻣﺤﺴﻮب ﻣﯿﺸﻮﻧﺪ و ﻧﯿﺰ ﺑﺎﺗﻮﺟﻪ ﺑﻪ اﻫﻤﯿﺖ ﮔﻮﺷﺖ ﻣﺮغ ﺑﻪ ﻋﻨﻮان ﯾﮑﯽ از ﻣﻨﺎﺑﻊ ﻣﻬﻢ ﺗﺎﻣﯿﻦ ﭘﺮوﺗﺌﯿﻦ ﺣﯿﻮاﻧﯽ دراﯾﺮان ، ﻫﺪف از اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﺑﺮرﺳﯽ ﺣﻀﻮر اﯾﻦ ژن در اﺷﺮﯾﺸﯿﺎ ﮐﻠﯽ ﻫﺎي ﺟﺪا ﺷﺪه از ﻣﻮارد ﮐﻠﯽ ﺑﺎﺳﯿﻠﻮز ﻃﯿﻮر در ﻧﻈﺮ ﮔﺮﻓﺘﻪ ﺷﺪ. ﺟﻬﺖ دﺳﺘﯿﺎﺑﯽ ﺑﻪ اﯾﻦ ﻣﻨﻈﻮر246 ﻧﻤﻮﻧﻪ اﺷﺮﯾﺸﯿﺎ ﮐﻠﯽﺟﺪا ﺷﺪه از ﮐﻠﯽ ﺑﺎﺳﯿﻠﻮز و 54 ﻧﻤﻮﻧﻪ ﺟﺪا ﺷﺪه از ﮐﻠﻮاك ﭘﺮﻧﺪﮔﺎن ﺑﻪ ﻇﺎﻫﺮ ﺳﺎﻟﻢ از ﭼﻨﺪﯾﻦ آزﻣﺎﯾﺸﮕﺎه داﻣﭙﺰﺷﮑﯽ ﺳﻄﺢ ﺷﻬﺮ ﺗﻬﺮان و ﻣﺰارع ﭘﺮورش ﻣﺮغ ﮔﻮﺷﺘﯽ ﺟﻤﻊ آوري ﮔﺮدﯾﺪه و ﺣﻀﻮر ژن ﺗﻮﻟﯿﺪ ﮐﻨﻨﺪه اﯾﻦ ﺗﻮﮐﺴﯿﻦ ﺑﺎ روش ﮐﻠﻮﻧﯽ ﻫﯿﺒﺮﯾﺪاﺳﯿﻮن ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ . ﺗﻨﻬﺎ62/1 درﺻﺪ از ﺳﻮﯾﻪ ﻫﺎي ﺟﺪا ﺷﺪه از ﻣﻮارد ﮐﻠﯽ ﺑﺎﺳﯿﻠﻮز واﺟﺪ اﯾﻦ ژن ﺗﺸﺨﯿﺺ داده ﺷﺪﻧﺪ .درحاليكه در هيچ يك از سويه هاي مدفوعي ژن عامل اين توكسين مشاهده نگرديد. ﺑﺎ ﺗﻮﺟﻪ ﺑﻪﻣﯿﺰان ﺣﻀﻮر ﮐﻢ اﯾﻦ ژن در ﺳﻮﯾﻪ ﻫﺎي ﺟﺪا ﺷﺪه از ﻃﯿﻮر ﻣﯿﺘﻮان اﻇﻬﺎر داﺷﺖ، ﮔﻮﺷﺖ ﻣﺮغ در اﻧﺘﻘﺎل اﯾﻦ ﺗﻮﮐﺴﯿﻦ از ﻃﺮﯾﻖ باكتري اﺷﺮﯾﺸﯿﺎ ﮐﻠﯽ نقش ﭼﻨﺪان ﻣﻮﺛﺮي ندارد. اﮔﺮﭼﻪ اﻧﺘﻘﺎل از ﻃﺮﯾﻖ ﺳﺎﯾﺮ ﺑﺎﮐﺘﺮﯾﻬﺎي ﮔﺮم ﻣﻨﻔﯽ ﺑﯿﻤﺎرﯾﺰا در ﻃﯿﻮرﻧﻈﯿﺮ ﮐﻤﭙﯿﻠﻮﺑﺎﮐﺘﺮدوراز اﻧﺘﻈﺎر ﻧﯿﺴﺖ.

Detection of Cytolethal distending toxin (cdt) genes in Escherichia coli isolates from poultry colibacillosis has been reported from variety of pathogenic Gram negative bacteria such as Escherichia coli, Escherichia albertii, Campylobacter spp and Shigella spp. CDT producing Escherichia coli (CTEC) has been isolated from patients with gastrointestinal, urinary tract infection and sepsis. Up to now the source of human infection remains unknown. Since meat and meat products have been incriminated as the predominant causes of many food borne infections and poultry meat is one of the most important sources of animal proteins in Iran, the purpose of this study was detection of Cytolethal distending toxin gene in Escherichia coli isolated from poultry colibacillosis. 246 Escherichia coli isolated from avian colibacillosis (APEC) and fifty-four fecal E.coli isolates from the feces of apparently healthy birds (AFEC) were investigated for the presence of cdt genes. Isolates collected from veterinary medicine laboratories in Tehran and detection carried out with colony hybridization assay. The results showed only 1.62% of isolates possess cdt gene. This finding indicates that poultry meat probably could not be the main reservoir of CTEC. However expression of CDT from other Gram negative bacteria in poultry meat is not unexpected.