Bayesian estimation of true prevalence, sensitivity and specificity of three diagnostic tests for detection of Escherichia coli O157 in cattle feces

Ekong, Pius S.; Sanderson, Michael W.; Bello, Nora M.; Noll, Lance; Cernicchiaro, Natalia; Renter, David G.; Bai, Jianfa; Nagaraja, T. G.

doi:10.1016/j.prevetmed.2017.10.002

Cited by 9 publications

(9 citation statements)

References 48 publications

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“…In this current study, diagnostic sensitivity of CUL was slightly greater than that of PCR-CUL, however, their 95% confident intervals overlapped. Conversely, the diagnostic specificity of CUL and PCR-CUL in this study were comparable to those seen in the Ekong et al (2017) and Ekong et al (2018) studies. While pooling decreased sensitivity for both tests, testing FP and BP by PCR-CUL produce comparable estimates of sensitivity, pending further testing of the IF sample constituting the positive pools.…”

Section: Discussionsupporting

confidence: 83%

“…Posterior estimates of diagnostic sensitivity and specificity for CUL and PCR-CUL methods for the detection of fecal Salmonella in adult dairy cows showed high and comparable results for IF samples, FP, and BP samples. The diagnostic specificity of CUL and PCR-CUL tests observed in the current study are comparable in magnitude to those recorded for culture and PCR methods for the detection of other foodborne fecal pathogens, Escherichia coli O157 and non-O157 serogroups (Ekong et al, 2017;Ekong et al, 2018). In the Ekong et al (2017) and Ekong et al (2018) studies, diagnostic sensitivity of the quantitative PCR method was greater than that of culture.…”

Section: Discussionsupporting

confidence: 75%

“…The diagnostic specificity of CUL and PCR-CUL tests observed in the current study are comparable in magnitude to those recorded for culture and PCR methods for the detection of other foodborne fecal pathogens, Escherichia coli O157 and non-O157 serogroups (Ekong et al, 2017;Ekong et al, 2018). In the Ekong et al (2017) and Ekong et al (2018) studies, diagnostic sensitivity of the quantitative PCR method was greater than that of culture. In this current study, diagnostic sensitivity of CUL was slightly greater than that of PCR-CUL, however, their 95% confident intervals overlapped.…”

Section: Discussionsupporting

confidence: 75%

“…External prior information for the model parameters were specified using beta distributions. A non-informative prior (dbeta(1,1)) was specified for all model parameters except for the specificity of CUL which was considered high (mode = 99%; 5th percentile = 97%) (Ekong et al, 2017). In addition, for the individual cow model, the prior for PCR-CUL sensitivity was set with a mode of 85.0% and 5th percentile of 50%, and PCR-CUL specificity was set with a mode of 95% and 5th percentile of 50% based on expert opinion.…”

Section: Statistical Analysis Estimation Of Diagnostic Sensitivity Anmentioning

confidence: 99%

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Bayesian estimation of diagnostic accuracy of fecal culture and PCR-based tests for the detection of Salmonella enterica in California cull dairy cattle

Adaska¹,

Ekong

Clothier³

et al. 2020

PeerJ

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Epidemiological studies of low prevalence disease problems are often hindered by the high cost of diagnostic testing. The objective of this study was to evaluate PCR screening of both individual and pooled fecal samples from culled dairy cows for the invA gene of Salmonella followed by culture to determine if the sensitivity and specificity were comparable to the results from traditional culture methods applied to individual samples. Cows from six different dairies were sampled in all four seasons. A total of 240 individual cow fecal samples, 24 fecal pools and 24 pools of 24-hour tetrathionate enrichment broth were tested. Diagnostic sensitivity of PCR screening followed by culture of PCR positive or indeterminate samples (i.e PCR-CUL method) was lower than that of culture (CUL) when applied to individual fecal samples (94.8%, 99.5%), however the specificity was comparable (99.6% and 97.7% respectively). For pools of five fecal samples and pools of five, 24 h tetrathionate broth samples, the specificity of both tests were comparable (∼98%); however, their sensitivity was only comparable in pooled fecal samples (∼93%) but greater for culture compared to PCR-CUL in pooled broth samples (∼99% versus ∼93%). Compared to culture results from testing of individual fecal samples, testing pooled fecal samples by culture had a relative sensitivity of 74% and relative specificity of 96%, testing pooled fecal samples by PCR-CUL resulted in relative sensitivity of 90% and relative specificity of 96%. Testing of pooled 24-hour enrichment broth by PCR-CUL increased the relative sensitivity and specificity to 100%. PCR testing followed by culture of positive or indeterminate samples is a time saving alternative to traditional methods. In addition, pooling of samples may be a useful method for decreasing cost if study aims can accommodate a moderate loss of relative sensitivity.

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Section: Discussionsupporting

confidence: 83%

Section: Discussionsupporting

confidence: 75%

Section: Discussionsupporting

confidence: 75%

Section: Statistical Analysis Estimation Of Diagnostic Sensitivity Anmentioning

confidence: 99%

See 2 more Smart Citations

Bayesian estimation of diagnostic accuracy of fecal culture and PCR-based tests for the detection of Salmonella enterica in California cull dairy cattle

Adaska¹,

Ekong

Clothier³

et al. 2020

PeerJ

Self Cite

View full text Add to dashboard Cite

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“…Lower cfu counts can be detected with decreased sensitivity. IMS has a specificity of 99% ( Ekong et al, 2017 ), and all positive isolates were confirmed as such by the Scottish E. coli Reference Laboratory. For the positive/negative analysis, an E. coli O157 positive cow was defined as one that tested positive by IMS.…”

Section: Methodsmentioning

confidence: 99%

Co-infection with Fasciola hepatica may increase the risk of Escherichia coli O157 shedding in British cattle destined for the food chain

Howell

Tongue

Currie

et al. 2018

Preventive Veterinary Medicine

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Escherichia coli O157 is a zoonotic bacterium that can cause haemorrhagic diarrhoea in humans and is of worldwide public health concern. Cattle are considered to be the main reservoir for human infection. Fasciola hepatica is a globally important parasite of ruminant livestock that is known to modulate its host’s immune response and affect susceptibility to bacterial pathogens such as Salmonella Dublin. Shedding of E. coli O157 is triggered by unknown events, but the immune system is thought to play a part. We investigated the hypothesis that shedding of E. coli O157 is associated with F. hepatica infection in cattle. Three hundred and thirty four cattle destined for the food chain, from 14 British farms, were tested between January and October 2015. E. coli O157 was detected by immunomagnetic separation and bacterial load enumerated. F. hepatica infection status was assessed by copro-antigen ELISA. A significant association (p = 0.01) was found between the log percent positivity (PP) of the F. hepatica copro-antigen ELISA and E. coli O157 shedding when the fixed effects of day of sampling and the age of the youngest animal in the group, plus the random effect of farm were adjusted for. The results should be interpreted cautiously due to the lower than predicted level of fluke infection in the animals sampled. Nevertheless these results indicate that control of F. hepatica infection may have an impact on the shedding of E. coli O157 in cattle destined for the human food chain.

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Development of a new real-time PCR for the detection of pilchard orthomyxovirus (POMV) in apparently healthy fish

et al. 2022

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Bayesian estimation of true prevalence, sensitivity and specificity of three diagnostic tests for detection of Escherichia coli O157 in cattle feces

Cited by 9 publications

References 48 publications

Bayesian estimation of diagnostic accuracy of fecal culture and PCR-based tests for the detection of Salmonella enterica in California cull dairy cattle

Bayesian estimation of diagnostic accuracy of fecal culture and PCR-based tests for the detection of Salmonella enterica in California cull dairy cattle

Co-infection with Fasciola hepatica may increase the risk of Escherichia coli O157 shedding in British cattle destined for the food chain

Development of a new real-time PCR for the detection of pilchard orthomyxovirus (POMV) in apparently healthy fish

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