Instituto Nacional de Tecnología Agropecuaria (INTA), Estación Experimental Agropecuaria, Concepción del Uruguay, Casilla de Correo Nº6, 3260, Entre Ríos, Argentina.
Poult Sci. 2013 Jan;92(1):225-32. doi: 10.3382/ps.2012-02254.
The present work compared 2 culture methods and PCR assays for motile and nonmotile Salmonella detection using artificially contaminated poultry drinking water. The specificity was 1 for all methods studied. The accuracy and sensitivity were 1 for all motile strains, whereas these parameters were between 0 and 0.7 for nonmotile Salmonella strains. The positive predictive value and negative predictive value were 1 for all motile Salmonella strains in the 3 methods used. Nonmotile Salmonella strains showed a positive predictive value of 1 in the PCR method. However, the positive predictive value was indeterminate in the tetrathionate (TT) methods for both strains tested and in the modified semisolid Rappaport-Vassiliadis (MSRV) method for Salmonella Pullorum. On the other hand, the negative predictive value was between 0.20 and 0.43 for the 3 methods. The detection level of motile strains was 4 to 7 cfu/25 mL for all methods. Nonmotile Salmonella strains could not be detected in the TT method, whereas only Salmonella Gallinarum could be recovered from 1.1 × 10(1) cfu/25 mL in the MSRV method. In relation to the molecular methods, PCR could detect these strains from 1.1 × 10(4) cfu/25 mL. Extending incubation time of the enrichment medium to 6 d in the TT method did not improve the isolation rates. In general, all selective plating media did not show any statistical differences in the parameters of performance studied. The kappa coefficient showed that there was an excellent agreement between the 3 methods for motile strains. For nonmotile strains, the agreement was poor between the MSRV and the PCR; there was no agreement when the TT method was compared with the MSRV and the PCR methods. The difference in detection levels obtained with the methods used for motile and nonmotile Salmonella strains and the difficulty in detecting these last strains represents a potential problem when a poultry water sample is considered negative for the presence of Salmonella.
本研究比较了两种培养方法和聚合酶链反应（PCR）检测方法，用于检测人工污染的家禽饮用水中的运动型和非运动型沙门氏菌。所有方法的特异性均为 1。对于所有运动型菌株，准确性和灵敏度均为 1，而对于非运动型沙门氏菌菌株，这些参数在 0 到 0.7 之间。在三种方法中，所有运动型沙门氏菌菌株的阳性预测值和阴性预测值均为 1。非运动型沙门氏菌菌株在 PCR 方法中显示阳性预测值为 1。然而，在两种测试的菌株中，在四硫酸盐（TT）方法中以及在沙门氏菌 Pullorum 的改良半固体 Rappaport-Vassiliadis（MSRV）方法中，阳性预测值不确定。另一方面，三种方法的阴性预测值在 0.20 到 0.43 之间。所有方法对运动型菌株的检测水平均为 4 至 7 cfu/25 mL。在 TT 方法中，无法检测到非运动型沙门氏菌菌株，而在 MSRV 方法中，仅能从 1.1 × 10(1) cfu/25 mL 中回收沙门氏菌 Gallinarum。关于分子方法，PCR 可以从 1.1 × 10(4) cfu/25 mL 中检测到这些菌株。将富集培养基的孵育时间延长至 TT 方法的 6 天并没有提高分离率。一般来说，所有选择性平板培养基在研究的性能参数方面没有显示出任何统计学差异。kappa 系数表明，三种方法对运动型菌株的一致性非常好。对于非运动型菌株，MSRV 与 PCR 之间的一致性较差；与 MSRV 和 PCR 方法相比，TT 方法之间没有一致性。对于运动型和非运动型沙门氏菌菌株，使用方法获得的检测水平差异以及最后这些菌株的检测难度，当考虑到禽用水样中不存在沙门氏菌时，这可能是一个潜在问题。
