ارزيابي دو روش هماگلوتيناسيون غيرمستقيم در تشخيص ليستريوز و مقايسه آنها با روش ايمونوفلورسانس غير مستقيم

Evaluating two indirect hemagglutination methods in diagnosis of listeriosis in comparison with indirect immunoflourecens

Introduction: Bacterimia resulted from Listeria monocytogenes leads to various complications including abortion. While culturing the specimen is a crucial method in diagnosing of listeriosis, it has low sensitivity (because of the few number of bacteria in specimens) and takes long time. Serological methods are used routinely in many diagnostic laboratories because of improved time and sensitivity. Materials and methods: IHA (indirect hemagglutination) was performed using fraction 1, obtained from gel chromatography of sonicated listeria monocytogenes crude antigens. IHA through potelʹs method was carried on. Sensitivity and specificity of these methods compared with current IFA (immunoflourecens assay) in diagnosing the Listeriosis. The titers of antibody against Listeria monocytogenes were determined in serums of 207 women having at least one abortion. Among this group serums of 96 women by IHA with soluble antigens in fraction 1 and 82 women by IHA with soluble antigen in potelʹs method were tested. Results: In IFA (sensitivity 70% and specificity 50%), 83.5% had valuable titers of antibody. Niether crude antigen nor three fractions were suitable for IHA, but all 82 serums (potelʹs method) showing 1/4 to 1/256 titers (sensitivity 36% and specificity 96%). Conclusion: IFA is the most current method but, because of high sensitivity and low specificity a more confident method is required. This study shows antigenic fractions of listeria monocytogenes are not suitable for IHA, while changing the condition of culture in potelʹs method leads to the applicable antigen for IHA. Lack of correlation between IFA and potelʹs IHA indicate that the nature of antigens are different in both methods. Thus it is recommended to use IFA for screening and simultaneously potelʹs IHA (because of high specificity).