Evaluation of bile salt No. 3, Novobiocin, and cefixime-tellurite in enrichment and/or selective plating media for detection of Escherichia coli 0157:H7 from ground beef

Bu çalışmada sığır eti kıymalarından E. coli 0157:H7 tayininde en sık kullanılan saplementlerin etkinliği sorbitol negatif floranın desteklenmesi ve sorbitol pozitif floranın (rekabetçi flora) en iyi şekilde baskılanması esasına göre araştırıldı. Safra tuzu ilave edilmemiş besi yeri (bile free modified E. coli broth, b-mEC)'ne safra tuzu (bile salts no. 3, 1,12 mg/ml), novobiosin (20 ug/ml), sefiksim (0,05 $mu$ g/ml)-tellurit (2,5 $mu$ g/ml) Saplementlerinin ayrı ayrı veya kombine olarak ilave edilmesi besi yerinin etkinliğini artırmadı. Sorbitol pozitif floranın bu sapiementlere sorbitol negatif floradan daha dirençli olduğu gözlendi. Sorbitol MacConkey agar ve E. coli 0157:H7 agar yaklaşık olarak aynı düzeyde selektif özellik gösterdi. Bu besi yerlerine sefiksim (0,05 $mu$ g/ml)-tellurit (2,5 $mu$ g/ml) saplement ilave etmekle selektiflikleri oldukça arttı ve saplement kullanımının uygun olduğu görüldü. Sonuç olarak, b-mEC gibi bir zenginleştirme besi yeri ve sefıksim-tellurit saplement içeren sorbitol bazlı bir katı besi yerinin kullanımının güvenilir olduğu gözlendi.

Kıymalardan Escherichia coli 0157: H7 izolasyonu amacıyla zenginleştirme ve/veya sorbitol bazlı katı besi yerlerinde kullanılan safra tuzları No. 3, Novobiosin ve sefiksim-Tellurit saplementlerinin değerlendirilmesi

Efficacy of commonly used selective supplements for detection of E. coli 0157:H7 from ground beef was evaluated for suppression of sorbitol positive flora while supporting recovery of sorbitol negative flora. Selectivity of bile free modified E. coli broth (b-mEC) was not improved by the single addition of bile salts no. 3 (1.12 mg/ml), novobiocin (20 $mu$ g/ml), cefixime (0.05 $mu$ g/ml)-tellurite (2.5 $mu$ g/ml), or their combinations. The sorbitol positive flora was more resistant to the selective agents than sorbitol negatives. Sorbitol MacConkey agar and E. coli 0157:H7 agar had almost equal selectivity. Adding cefixime (0.05 pg/ml)-tellurite (2.5 $mu$ g/ml) to the selective plating media highly enhanced the selectivity, and a general sorbitol based plating medium without cefixime-tellurite is not appropriate for this purpose due to its nonselectivity. As a result, a bile-free enrichment broth such as b-mEC and a sorbitol based selective plating, medium containing cefixime-tellurite appeared to be reliable.

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