Real-time PCR for detection and differentiation of Streptococcus equi subsp. equi and Streptococcus equi subsp. zooepidemicus

Båverud, Viveca; Johansson, Sara; Aspán, Anna

doi:10.1016/j.vetmic.2007.04.020

Cited by 88 publications

(88 citation statements)

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“…equi (S. equi) is a pathogen solely of the horse. Verification of strangles requires detection of S. equi by bacterial culture, PCR, or both [2][3][4] on samples from the upper respiratory tract. Various sampling methods to detect S. equi are suggested, including use of nasal swabs, nasopharyngeal swabs 5 , nasopharyngeal lavages, [6][7][8] or even lavages from the guttural pouches.…”

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confidence: 99%

Comparison of Sampling Sites and Laboratory Diagnostic Tests for S. equi subsp. equi in Horses from Confirmed Strangles Outbreaks

Lindahl

Båverud

Egenvall

et al. 2013

Veterinary Internal Medicne

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Background: Strangles is a contagious equine-specific disease caused by Streptococcus equi subsp. equi. Unfortunately, detection of S. equi can fail in up to 40% of horses with strangles. Whereas recent molecular biologic methods and sampling techniques have improved recovery of S. equi optimal sampling methods and laboratory analyses remain ill-defined.Objectives: To determine the yield of S. equi from horses with acute strangles in confirmed outbreaks by field-sampling methods subjected to culture and biochemical identification, and real-time PCR directly and after culture.Animals: Fifty-seven horses of varying breeds and ages from 8 strangles outbreaks. Methods: Prospective study. Culture with biochemical identification and real-time PCR directly, and from culture, were performed on nasal swabs, nasopharyngeal swabs, and nasopharyngeal lavages.Results: Real-time PCR directly from samples identified the highest number of infected horses, with 45/57 nasal swabs, 41/57 nasopharyngeal swabs, and 48/57 nasopharyngeal lavages S. equi positive. Biochemical identification (highest positives 22/57) was inferior to real-time PCR for S. equi recovery regardless of sampling method. Real-time PCR of nasopharyngeal lavage directly and after culture yielded 52/57 positives whereas direct real-time PCR of nasopharyngeal lavage combined with either nasopharyngeal swabs or nasal swabs yielded 53/57 positives. Three horses were negative on all samples.Conclusions and Clinical Importance: Nasopharyngeal lavage analyzed by a combination of real-time PCR directly and after culture or, alternatively, real-time PCR directly on a nasopharyngeal lavage and a nasal/nasopharyngeal swab can identify S. equi in over 90% of acute strangles cases.

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Comparison of Sampling Sites and Laboratory Diagnostic Tests for S. equi subsp. equi in Horses from Confirmed Strangles Outbreaks

Lindahl

Båverud

Egenvall

et al. 2013

Veterinary Internal Medicne

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“…S2), However, sodA shows a high degree of similarity between the strains and so it is a perfect candidate for a primer set able to detect Streptococcus spp. (Alber et al, 2004;Båverud et al, 2007).…”

Section: Primer Designmentioning

confidence: 99%

“…At the genomic level the two subspecies, S. equi and S. zooepidemicus, are very closely related sharing a large portion of the genome, therefore only few areas are suitable to be chosen for assays enabling differentiation between them (Båverud et al, 2007;Webb et al, 2008;Holden et al, 2009). Previous studies have focused on designing the PCR primers in the region of the genome that encodes the super-antigenic toxin seeH and seeI (Alber et al, 2004;Båverud et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies have focused on designing the PCR primers in the region of the genome that encodes the super-antigenic toxin seeH and seeI (Alber et al, 2004;Båverud et al, 2007). However, there are concerns that the genes encoding for antigenic proteins are more prone to mutation due to the selective pressure of the immune host's system leading to false negative test results (Alber et al, 2004;Laus et al, 2007;Preziuso and Cuteri, 2012).…”

Section: Introductionmentioning

confidence: 99%

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

Cordoni

Williams

Durham³

et al. 2015

Research in Veterinary Science

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“…Phenotypic classification remains controversial (1,2,3), and the use of molecular targets to discriminate between S. equi subsp. zooepidemicus and subsp.…”

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Illustration of the Difficulty of Identifying Streptococcus equi Strains at the Subspecies Level through a Case of Endocarditis in an Immunocompetent Man

et al. 2014

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dWe report a case of endocarditis caused by Streptococcus equi in an immunocompetent patient who was subsequently cured after appropriate antibiotherapy and cardiac surgery. However, it was challenging to identify the strain to the subspecies level, which highlights the necessity of developing reliable molecular tools to discriminate between the subspecies. CASE REPORT In January 2012, a 63-year-old man presented to the emergency room with a 2-week history of low-grade fever but without other symptoms and reported self-treatment with paracetamol. Past medical history included pituitary adenoma, which was treated by surgery in 1989, and a mechanical aortic valve replacement in December 2008 as treatment for severe aortic insufficiency.At admission, he had no fever (37.2°C), was under treatment with paracetamol, and had a pulse rate of 71/min. His blood pressure was 128/91 mm Hg, and oxygen saturation was 97% on air. An erythematous skin rash on his forehead extending to his right infraorbital area, which appeared a few hours before admission, was noted. No other skin lesions were apparent by physical examination. Cardiac auscultation was normal, and no signs of cardiac failure were found. Electrocardiogram revealed a second-degree atrioventricular block, while neurological, abdominal, and respiratory examinations were normal. The thoracic computed tomography scan was normal, transthoracic and transesophageal echocardiographies (TTE and TEE) did not show any vegetation or signs of endocarditis, and the mean transaortic valve gradient was close to 35 mm Hg without pathological regurgitation.Initial laboratory investigations revealed a leukocyte count of 10,100/mm 3 (75% neutrophils) (8,000 to 10,000/mm 3 ), the C-reactive protein concentration was 30 mg/liter (normal, Ͻ4 mg/liter), and his serum electrolyte assay results, troponin level, and international normalized ratio (INR) were normal. On the third day, pyrexia and confusion were observed. Blood cultures were performed daily, and cultures were incubated in a BacT/Alert automated system (Organon Teknika, bioMéri-eux). Aerobic and anaerobic bottles (eight out of nine sets) obtained during the febrile period were positive within 24 h, and Gram-positive coccus chain formation suggestive of Streptococcus was seen upon Gram staining.A subculture of the bacterium was obtained within 24 h of incubation on horse blood agar and on chocolate agar (bioMérieux, Marcy l'Etoile, France). The colonies were 0.5 to 1 mm in diameter, round, mucoid, glistening, nonpigmented, catalase negative, and beta-hemolytic. Gram staining demonstrated thin, short to medium-length, Gram-positive, non-spore-forming cocci suggestive of Streptococcus. The strain was identified as Lancefield group C, and rapid ID 32 Strep and API 20 Strep (bioMérieux) results were Streptococcus equi subsp. zooepidemicus (probability, 99.7%). However, the following phenotypical characteristics led to an identification as Streptococcus equi subsp. ruminatorum: the CAMP reaction was positive, and the strain hydrolyz...

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Real-time PCR for detection and differentiation of Streptococcus equi subsp. equi and Streptococcus equi subsp. zooepidemicus

Cited by 88 publications

References 16 publications

Comparison of Sampling Sites and Laboratory Diagnostic Tests for S. equi subsp. equi in Horses from Confirmed Strangles Outbreaks

Comparison of Sampling Sites and Laboratory Diagnostic Tests for S. equi subsp. equi in Horses from Confirmed Strangles Outbreaks

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

Illustration of the Difficulty of Identifying Streptococcus equi Strains at the Subspecies Level through a Case of Endocarditis in an Immunocompetent Man

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