تهيه و ارزيابي آنتي ژن رنگي به منظور غربال گري سرولوژيك عفونت سالمونلايي

Preparation and evaluation of colored antigen for serological screening of Salmonella infections

سالمونلوز از بيماري هاي عفوني بسيار مهم و شايع بوده كه همه ساله افراد زيادي را مبتلا مي سازد. علت اين امر‏، طيف گسترده ميزبان ها و تعداد زياد سروتيپ هاي جنس سالمونلا است. از آن جا كه اختلاف آنتي ژني بين سروتيپ ها وجود دارد، ابتلاي به يك سروتيپ از عفونت با ساير سروتيپ ها كه متعلق به گروه هاي ديگر هستند جلو گيري نمي كند. خوشبختانه با اقدام هاي انجام شده در ايران از وقوع سالمونلوز تيفوييدي كاسته شده ليكن اشكال غير تيفوييدي سالمونلوز هم چنان وقوع بالايي دارد. تشخيص سالمونلوز از طريق نشانه هاي باليني مشكل است زيرا نشاني اختصاصي وجود ندارد و بسياري از علايم آن مشابه ساير بيماري ها است. بنابراين تشخيص آزمايشگاهي ضروري است. از آن جا كه جدا سازي باكتري وقت گير بوده و در مطالعه هاي اپيدميولوژيك به ويژه در مناطق دور افتاده عملي نيست غالباً از آزمايش هاي سرم شناسي براي تشخيص استفاده مي شود. هدف از انجام اين تحقيق ارزيابي آنتي ژن رنگي به منظور تشخيص اوليه و سريع سالمونلوز ناشي از گروه سرمي B سالمونلا بود.

Salmonellosis is concidered as one of the most widespread infectious diseases in industrialised as well as developing countries because of wide range of Salmonella serotypes and different resourses. Fortunately the incidence of thyphoid fever has decreased but non-typhoidal salmonellosis has increased in recent years. Clinical diagnosis by signs and symptoms is very difficult because they are not specific. Different methods have been used for laboratory diagnosis of Salmonella infections that include isolation of bacteria and serological methods. The serological methods are popular in developing countries since the isolation of bacteria is time consuming and is not suitable for epidemiological studies. The aim of this study was evaluation of rapid slide agglutination test (SAT) in primary diagnosis of salmonellosis caused by group B Salmonella. Four hundred and thirty five blood samples were collected from 262 and 173 male and female outpatients respectively in Esfahan, Iran. The presense of anti-salmonella antibodies determined by SAT using coloured antigen. The anti-salmonella titres of all sero-positive and 50 sero-negative sera were determined by tube agglutination (Widal O) and slide tests. One hundred and twenty four ( 28.5%) sera were positive and 311 (71.5%) were negative by SAT. The anti-salmonella antibodies titre of 51( 41.1%), 44 (35.5%), 21( 16.4%) and 8 (6.5%) were < 20, 20, 40 and 80 respectively. The GMT (geometrical mean titre) of positive samples was 27.8. At all, 6.5% of samples were seropositive included 62.5% female and 27.5% male. The mean of WBC in patients with titre equal or more than 80 was 8675. There was a significant difference between WBC of titre 80 and < 80 but no difference between titre 80 and < 20 (p < 0.05). So WBC count is not a valuable factor in primary diagnosis of seropositive samples. None of seronegative sera in SAT showed positive results by Widal test. We found that SAT with coloured antigen is a rapid test for serological screening of suspected cases of salmonellosis or epidemiological study especially if it will done by 1:20 dilution of serum sample. Keywords: salmonella typhimurium, screening test, couloured antigen