Evaluation of Potential Usage of Antigens Prepared from Some Bacterial Genera of Alpha-Proteobacteria in Serologic Diagnosis of Brucellosis

Abstract

Brusellosis is an important zoonosis that cause serious infections in man and animals. This infection constitutes a risk for public health and big economical losses in animal industry. Serological tests have been intensively used for serologic diagnosis of brucellosis because these tests are quicker and more practical than culturing of the causative organisms. Antigens used in serological tests are prepared from virulent Brucella strains. In this regard, to use antigens prepared from bacterial strains that are not virulent for human and genetically close to Brucella spp. in the serological dagnosis of the disease will be a desired approach. These organisms have much lower virulence than Brucella and generally they are considered as saphrophytic bacteria and some of them are oppurtunistic pathogen like O. anthropi. In this study, we planned to search the possibility of usage of antigens prepared from three bacterial species of alpha-Proteobacteria (Ochrobactrum anthropi, O intermedium, Rhizobium tropici) which are filogenetically close to Brucella. As conclusion, none of the antigens yielded acceptable sensitivity and specificity for cattle and human brucellosis. Only sheep and dogs sera against O. intermedium, which is a rough species and carry R-LPS instead of S-LPS, showed diagnostic performance in acceptable ranges. When considering all the results of the study, it was thought that some members of alpha Proteobacteria might cause cross reaction in the serologic diagnosis of brucellosis and cause false positive reactions and this should be remembered when evaluating the serologic diagnosis of brucellosis. On the other hand, pure antigens from O. intermedium might have the potential to be used in B. ovis and B. canis infections and it was thought that the future works in this field might be needed.

Alfa-proteobacteria Grubuna Ait Bazı Bakteri Cinslerinden İzole edilen antijenlerin Brusellozisin Serolojik Tanısında Potansiyel Uygulanabilirliğinin Araştırılması

Abstract

Brusellozis insanlarda ve hayvanlarda önemli enfeksiyonlara neden olan, halk sağlığını tehdit eden ve hayvancılık endüstrisine ciddi ekonomik kayıplara neden olan zoonoz bir enfeksiyondur. Bu çalışmada, Brucella suşları ile filogenetik yakınlığı bulunan alfa–Proteobacteria sınıfına ait Ochrobactrum anthropi, O. intermedium ve Rhizobium tropici türlerinden hazırlanan antijenlerin brusellosizin serolojik tanısında Brucella antijeni yerine kullanılıp kullanılamayacağının ortaya konulması amaçlandı. Çalışmada, test serumlarına pozitif ve negatif kontroller ile birlikte indirekt ELISA uygulandı. Sonuç olarak, sığır ve insan brusellozisi açısından test edilen antijenlerin hiçbiri güvenilir düzeyde sensitivite ve spesifisite göstermedi. Çalışmada, sadece R-LPS taşıyan O. intermedium antijeni ile ve sadece koyun ve köpeklerde kısmen kabul edilebilir sınırlarda bir tanısal performans alındı. Sonuç olarak, proteobakterilerin α-2 alt grubunda yer alan mikroorganizmaların brusellozisin indirekt teşhisinde bazı çapraz reaksiyonlara neden olabileceği ve bu durumun yanlış pozitiflik yaratabileceği saptandı. Öte yandan bu grup bakterilerden hazırlanan daha saf antijenlerin, B. canis ve B. ovis infeksiyonlarında kullanılma potansiyeli bulunabileceği ve bu yönde yapılacak çalışmalara ihtiyaç olduğu kanısına varıldı.

Keywords

• alfa-Proteobacteria
• Brucella
• seroloji

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