پلي مورفيسم ژن هاي پرتاكتين (prn) و فيمبريه (fim) در سويه هاي بوردتلا پرتوسيس جدا شده از بيماران ايراني مشكوك به سياه سرفه

Polymorphism in the Bordetella pertussis Virulence Factors Pertactin and Fimbriae in Iran

سابقه و هدف:سياه سرفه يك عفونت حاد و كاملا مسري است كه عامل آن بوردتلاپرتوسيس، باكتري گرم منفي و منحصراً در انسان ايجاد بيماري مي نمايد. به رغم پوشش بالاي واكسيناسيون در كشورهاي توسعه يافته و درحال توسعه عليه بيماري سياه سرفه،افزايش بروز اين بيماري در بسياري از اين كشورها از جمله ايران،مشاهده شده است. يكي از فاكتورهاي احتمالي دخيل در شيوع مجدد سياه سرفه،پلي مورفيسم ژن هاي فاكتورهاي ويرولانس باكتري مي باشد. پرتاكتين و فيمبريه ازجمله فاكتورهاي ويرولانس مهم باكتري مي باشند. هدف از اين مطالعه، تعيين پلي مورفيسم ناحيه 1ژن prnو ژن mif3در سويه هاي در گردش جامعه و مقايسه آن با سويه واكسن مي باشد. روش كار:در اين مطالعه، 35سويه بوردتلا پرتوسيس جداشده از بيماران سياه سرفه ازسراسر ايران،كه مورد تائيد آزمايشگاه مرجع سياه سرفه انستيتو پاستور ايران بودند، بررسي شد. ناحيه 1ژن prn و ژن mif3 توسط PCR تكثير شد و محصولات PCR آنها براي تشخيص آلل ژن ها،تعيين توالي شد. .هم چنين سويه استاندارد واكسن ( 134 )نيز بررسي شد. يافته ها: تمامي سويه هاي بوردتلاپرتوسيس مورد بررسي جز 1سويه، داراي آلل prn 2و fim 3-2بودند. درحالي كه آلل هاي سويه واكسن nrp1 و mif3-1بود. نتيجه گيري : در بررسي هايي كه در بسياري از كشورهاي اروپايي و آمريكايي با پوشش واكسيناسيون بالا صورت گرفته است،نتيجه اي مشابه نتيجه اين تحقيق بدست آمده است و همگي آنها،آلل هاي غالب prn 2و fim 3-2را نشان داده اند.با توجه به اهميت پلي مورفيسم ژن هاي كدكننده فاكتورهاي ويرولانس وايمونوژن باكتري بوردتلا پرتوسيس،استفاده از سويه هاي بومي داراي آلل هاي غالب اين فاكتورها درتهيه واكسن موثر عليه پرتوسيس بسيار حائز اهميت بوده و بنابراين تحقيقات گسترده تري دررابطه باساير فاكتورهاي ويرولانس در سويه هاي در گردش جامعه لازم ميباشد.

Background an‎d Objective whooping cough is an acute and contagious infection that caused by Bordetella pertussis, a gram negative and human-specific pathogen. In the last decade, despite high vaccination coverage against pertussis in developed and developing countries, pertussis has reemerged in many countries including Iran. Among several reason of resurgence of pertussis, one of the most important factors in outbreak of the disease might be polymorphism and genetic variation of virulence genes of bacteria. pertactin is considered as one of the important virulence factors in B.pertussis and Polymorphism in pertactin is essentially limited to region 1. Fimbriae or pillus antigens of B. pertussis have been shown to be one of the many adhesions present on the surface of the bacteria. The purpose of this research was to study polymorphism of region 1 of prn gene and fim3 gene in circulating isolates and compare with vaccine strains. Materials an‎d Methods We examined 35 isolates isolated from nasopharyngeal specimen collected in 2008-2012.These strains have also been identified by biochemical and slide agglutination tests. Region 1 of prn gene and the fim3 gene in these isolates of B. pertussis were amplified by using specific primers by PCR method. Then we sequenced genes and analyzed our results by chromas and mega4 software. We examined also vaccine strain (134) . Result Our results showed that all examined strains have prn and fim3 gene in their genome in size 600 bp and 800 bp,respectively, as a partial codon. Also 34 strains have prn 2 and fim3-2 alleles and only one strain has prn 1 and fim3-1 allele. strain 134 showed prn 1 and fim 3-1 alleles. Conclusion In studies that have been done in most European and American countries with high vaccination coverage, similar results have been seen and predominant alleles were prn2 and fim3-2. We also obtained prn2 and fim3-2 as a predominant allele in our result. This study is performed for the first time in Iran. Investigation in the world suggest that vaccination has selected for strains which are antigenically distinct from vaccine strains, also considering the importance of polymorphism genes encoding virulence and immunogenic factors of B. pertussis, it's very important to use the clinical strain that has dominant alleles of these virulence factors for production of effective vaccine against pertussis. Consequently, it seems that more research is needed on the polymorphism of other virulence factors of B. pertussis in circulating strains in our country.