Wilkins Wendy, Waldner Cheryl, Rajić Andrijana, McFall Margaret, Chow Eva, Muckle Anne
Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan.
Can J Vet Res. 2011 Oct;75(4):308-11.
Among grow-to-finish pigs from 10 herds in Alberta and Saskatchewan, 23 (16%) of 144 fecal samples were culture-positive and 40 (28%) of 144 pigs were seropositive for Salmonella. With a Bayesian model specifying dependence between the 2 tests, the sensitivity (Se) of culture and real-time polymerase chain reaction (RT-PCR) was 79% to 86%, depending on the cut-off value for the enzyme-linked immunosorbent assay (ELISA). Culture specificity (Sp) was assumed to be 100%; RT-PCR Sp was found to be 94%. The ELISA Se was 76% and 51% at optical density cut-off values ≥ 20% and ≥ 40%, respectively; the Sp was 94% at each cut-off value. The model showed some sensitivity to ELISA prior information, the ELISA Se being approximately 8% lower when informative prior information was specified in the model. When there was no adjustment for dependence between culture and RT-PCR, the posterior estimates for both culture and RT-PCR Se were 11% higher than with the conditional-dependence model and had considerably narrower probability intervals, which suggests that correlation between culture and PCR is important and should be adjusted for in future studies.
在来自艾伯塔省和萨斯喀彻温省10个猪群的生长育肥猪中，144份粪便样本中有23份（16%）培养呈阳性，144头猪中有40头（28%）沙门氏菌血清呈阳性。使用一个指定两种检测方法之间存在依赖性的贝叶斯模型，培养和实时聚合酶链反应（RT-PCR）的敏感性（Se）为79%至86%，具体取决于酶联免疫吸附测定（ELISA）的临界值。培养特异性（Sp）假定为100%；发现RT-PCR的Sp为94%。在光密度临界值分别≥20%和≥40%时，ELISA的Se分别为76%和51%；在每个临界值下Sp均为94%。该模型显示对ELISA先验信息有一定敏感性，当在模型中指定信息性先验信息时，ELISA的Se约低8%。当未对培养和RT-PCR之间的依赖性进行调整时，培养和RT-PCR的Se的后验估计值比条件依赖性模型高11%，且概率区间明显更窄，这表明培养和PCR之间的相关性很重要，在未来研究中应进行调整。
