Optimization of an in vitro assay to detect Streptococcus equi subsp. equi

Boyle, Ashley G.; Boston, Ray; O’Shea, Kathleen; Young, Sheri; Rankin, Shelley C.

doi:10.1016/j.vetmic.2012.04.014

Cited by 15 publications

(30 citation statements)

References 20 publications

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“…PCR has been demonstrated to be a more sensitive technique for detecting S. equi on clinical swabs than culture (Newton et al, 2000;Lindahl et al, 2013); with many more true positive swabs detected using PCR than culture (92% vs. 30% of 61 swabs positive, respectively). Similar results were obtained for guttural pouch samples from 12 established S. equi carriers (PCR 76% vs. culture 59% positive) (Newton et al, 2000;Boyle et al, 2012). PCR also allows differentiation of the two subspecies, S. equi and S. zooepidemicus.…”

Section: Introductionsupporting

confidence: 71%

Rapid diagnosis of strangles (Streptococcus equi subspecies equi) using PCR

Cordoni

Williams

Durham³

et al. 2015

Research in Veterinary Science

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Section: Introductionsupporting

confidence: 71%

Rapid diagnosis of strangles (Streptococcus equi subspecies equi) using PCR

Cordoni

Williams

Durham³

et al. 2015

Research in Veterinary Science

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“…The limit of detection [6] and its use in detection of S. equi in clinical nasopharyngeal wash samples and guttural pouch lavage samples from sick, convalescent, and asymptomatic horses [19] has been published by our laboratory. DNA was extracted from a 1 ml aliquot of the guttural pouch lavage using PrepMan Ultra as described by the manufacturer (Applied Biosystems, Foster City, CA).…”

Section: Methodsmentioning

confidence: 99%

“…Bacterial culture and PCR of nasopharyngeal wash and guttural pouch lavage (GPL) specimens have been used to detect S. equi for diagnostic testing of clinical suspects and for the detection of carrier animals [2, 3, 5]. Bacterial culture has been documented to have low sensitivity when there are low numbers of S. equi [6]. PCR is highly sensitive and specific when the target DNA is present in the specimen.…”

Section: Introductionmentioning

confidence: 99%

“…Detection of S. equi carriers is influenced by several factors that include: 1) site of specimen collection (rostral nasal passage, nasopharynx versus guttural pouch; 2) method of sampling (flocked swab, rayon swab, versus wash); 3) culture versus PCR, 4) target gene of the PCR; and 5) DNA amplification method [1, 6–8]. It is well established that S. equi is harbored in the guttural pouch and that there is intermittent shedding of organisms into the nasopharynx [3, 5].…”

Section: Introductionmentioning

confidence: 99%

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Comparison of nasopharyngeal and guttural pouch specimens to determine the optimal sampling site to detect Streptococcus equi subsp equi carriers by DNA amplification

2017

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Background Streptococcus equi subsp equi (S. equi) is the cause of “equine strangles” which is a highly infectious upper respiratory disease. Detection of S. equi is influenced by site of specimen collection, method of sampling, and type of diagnostic test that is performed. We hypothesized i) that a loop-mediated isothermal amplification (LAMP) assay that targets the S. equi-specific eqbE gene would be more sensitive than a realtime PCR assay that targets the S. equi-specific seeI gene and ii) that LAMP of specimens obtained by guttural pouch lavage (GPL) would be more sensitive than LAMP of nasopharyngeal specimens to identify S. equi carriers.MethodsA nasopharyngeal flocked swab, nasopharyngeal wash, and GPL specimen was collected from 44 convalescent horses and the eqbE LAMP assay was performed. The seeI realtime PCR assay and aerobic culture were also performed on the GPL specimen. Logistic regression was performed to compare sampling sites and test methods (P-values ≤0.05 were considered significant).ResultsOne of 41 nasopharyngeal flocked swabs, 6/38 nasopharyngeal wash and 24/44 GPL specimens were positive by eqbE LAMP. 18/44 GPL specimens were positive by seeI PCR and S. equi was isolated from 4/44 of these specimens. Detection of S. equi DNA was 51 times more likely from the GPL samples than nasopharyngeal samples (OR 51.0, P < 0.0001). When eqbE LAMP GPL samples were positive, it was eight times more likely that the guttural pouch had any abnormality on endoscopy (OR 8.2, P ≤ 0.005), almost 20 times more likely that mild empyema was found (OR 19.7, P ≤ 0.002), and eight times more likely that the SeeI PCR was positive for S. equi DNA (OR 8.1, P ≤ 0.006).ConclusionThis study demonstrates that guttural pouch lavage specimens should be used to detect S. equi and that the eqbE LAMP assay was comparable to the seeI PCR.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-017-0989-4) contains supplementary material, which is available to authorized users.

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“…Nonetheless, PCR is sensitive and key for identification of infected animals. [26][27][28] Serologic testing is also available and useful for a few specific subsets of affected horses. Unfortunately, serology is not adequate for diagnosis of routine cases or inapparent shedders in the equine population.…”

Section: Diagnosismentioning

confidence: 99%

Update on Streptococcus equi subsp equi Infections

Mallicote

2015

Veterinary Clinics of North America: Equine Practice

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Optimization of an in vitro assay to detect Streptococcus equi subsp. equi

Cited by 15 publications

References 20 publications

Rapid diagnosis of strangles (Streptococcus equi subspecies equi) using PCR

Rapid diagnosis of strangles (Streptococcus equi subspecies equi) using PCR

Comparison of nasopharyngeal and guttural pouch specimens to determine the optimal sampling site to detect Streptococcus equi subsp equi carriers by DNA amplification

Update on Streptococcus equi subsp equi Infections

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