Ahmet VURAL, İlhan AFŞAR, Nükhet KURULTAY, Mustafa DEMİRCİ

Staphylococcus Aureus’da metisilin direncinin saptanmasında disk difüzyon, oksasilin agar tarama, mikrodilüsyon ve PBP2a lateks aglütinasyon testlerinin karşılaştırılması

Hastane ve toplum kökenli metisiline dirençli Staphylococcus aureus (MRSA) infeksiyonları dünyada yaygındır. Metisilin direncinin doğru olarak belirlenmesi uygun antimikrobik ilacın kullanımını sağlamak için gereklidir. Metisiline direncin heterojen olması nedeniyle fenotipik yöntemler ile tespitinde problemler olabilmektedir. Bu çalışmada MRSA tespitinde kullanılan çeşitli testlerin duyarlılık ve özgüllüklerinin karşılaştırılması amaçlanmıştır. Çalışmaya 117 S.aureus suşu alınmış, suşların metisilin direncini belirlemek için oksasilin (1 μg) ve sefoksitin (30 μg) disk difüzyon testi, oksasilin agar tarama, PBP2a lateks aglütinasyon, manuel oksasilin mikrodilüsyon ve otomatize sistem sefoksitin mikrodilüsyon testi uygulanmıştır. MRSA tanısında mikrodilüsyon testleri referans olarak alınmıştır. Oksasilin disk difüzyon, sefoksitin disk difüzyon, oksasilin agar tarama ve PBP2a lateks aglütinasyon testlerinin duyarlılıkları % 100 ve özgüllükleri sırasıyla % 100, % 100, % 100 ve % 97 olarak bulunmuştur.

Comparison of disk diffusion, oxacillin agar screening, microdilution and PBP2a latex agglutination tests for detection of methicillin resistance in Staphylococcus Aureus

Hospital and community acquired MRSA infections are common worldwide. Detection of methicillin resistance is essential for the use of appropriate antibiotics. The detection of methicillin resistance is complicated by the fact that its phenotypic expression in many strains is heterogeneous. We aimed to compare the sensitivity and specificity of several tests in detection of meticillin resistance. In this study, 117 S.aureus strains were tested. Methicillin resistance was evaluated by oxacillin (1 μg) disk diffusion test, cefoxitin (30 μg) disk diffusion test, oxacillin agar screening, manual oxacillin microdilution, automated cefoxitin microdilution and PBP2a latex agglutination tests. Microdilution tests were taken as reference on MRSA diagnosis. The sensitivities of oxacillin disk diffusion, cefoxitin disk diffusion, oxacillin agar screening and PBP2a latex agglutination tests were found as 100 % and specificities as 100 %, 100 %, 100 % and 97 %, respectively.

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