scholarly journals Group A Streptococcus Testing in Pediatrics: the Move to Point-of-Care Molecular Testing

2020 ◽  
Vol 58 (6) ◽  
Author(s):  
Thomas Z. Thompson ◽  
Allison R. McMullen

ABSTRACT Each year, there are an estimated 11 million visits to ambulatory care centers for pharyngitis in children between the ages of 3 and 18 years. While there are many causes of pediatric pharyngitis, group A streptococcal pharyngitis represents 15 to 30% of infections and is the only cause for which treatment is recommended. Unfortunately, clinical suspicion is insufficient for the accurate diagnosis of group A streptococcal pharyngitis, and laboratory testing for confirmation of Streptococcus pyogenes infection is required to prevent complications of infection. Traditionally, throat swabs are inoculated onto agar plates for isolation of the large-zone beta-hemolytic streptococcus. However, traditional culture methods present a potential delay in treatment due to turnaround times of 18 to 48 h. In order to improve turnaround times and enhance antimicrobial stewardship, multiple point-of-care assays have been developed. This review describes current point-of-care testing for group A streptococcal pharyngitis, including rapid antigen detection tests and more recent molecular methods. Additional attention is given to the diagnostic considerations when choosing a method for group A streptococcal point-of-care testing, implementation of molecular group A streptococcal testing, and the institutional cost of immunoassays compared to those of newer molecular methods.

2018 ◽  
Vol 3 (3) ◽  
pp. 429-437 ◽  
Author(s):  
Tam T Van ◽  
Javier Mestas ◽  
Jennifer Dien Bard

Abstract Background Group A Streptococcus (GAS) and large colony-forming group C (GCS) and G (GGS) β-hemolytic streptococci are important causes of acute pharyngitis in children and adults. Rapid and accurate diagnosis of streptococcal pharyngitis can improve patient care and potentially reduce transmission. In this study, we evaluated the performance of the Lyra Direct Strep (LDS) assay for detection of GAS and GCS/GGS compared with traditional culture methods. Methods Pharyngeal samples obtained from 278 children presenting to the emergency department with initial negative GAS rapid antigen detection test (RADT) were used. All samples were cultured as part of routine care and tested in batches using the LDS assay. Results Of 278 pharyngeal samples with negative GAS RADT, 37 (13.3%) and 63 (22.7%) patients were positive for GAS by culture and LDS assay, respectively. Four (1.4%) patients were positive for GCS or GGS by culture or LDS assay. The LDS assay demonstrated sensitivity and specificity of 97.6% and 89.0%, respectively, compared with culture as the gold standard. Repeat culture and an alternate PCR showed that 85.7% (24 of 28) of discrepant samples agreed with findings of the LDS assay. Since implementation, the LDS assay shows a positivity rate of 21.0% (281 of 1340) compared with 11.7% (246 of 2110) by culture in the previous year. Conclusions We successfully implemented the LDS assay at our institution and have observed a significant increase in the positivity rate of GAS compared with culture. The LDS assay alone allowed for the elimination of β-streptococci screening by culture at our institution.


2019 ◽  
Vol 57 (Supplement_3) ◽  
pp. S259-S266 ◽  
Author(s):  
P Lewis White

Abstract The field of diagnostic mycology represents much more than culture and microscopy and is rapidly embracing novel techniques and strategies to help overcome the limitations of conventional approaches. Commercial molecular assays increase the applicability of PCR testing and may identify markers of antifungal resistance, which are of great clinical concern. Lateral flow assays simplify testing and turn-around time, with potential for point of care testing, while proximity ligation assays embrace the sensitivity of molecular testing with the specificity of antibody detection. The first evidence of patient risk stratification is being described and together with the era of next generation sequencing represents an exciting time in mycology.


2018 ◽  
Vol 14 (4) ◽  
pp. 356-359 ◽  
Author(s):  
Donald G. Klepser ◽  
Michael E. Klepser ◽  
Jaclyn K. Smith ◽  
Allison M. Dering-Anderson ◽  
Maggie Nelson ◽  
...  

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S18-S19
Author(s):  
James Ray Mata Lim ◽  
Bobby L Boyanton ◽  
Julie George ◽  
Matthew Sims

Abstract Background Treatment of Group A Streptococcus (GAS) pharyngitis is imperative to mitigate sequelae such as rheumatic heart disease. The need for treatment of Group C Streptococcus (GCS) and Group G Streptococcus (GGS) pharyngitis is unclear, as rheumatogenic sequelae have not been well documented. Our institution switched from culture to molecular confirmation testing for a negative rapid streptococcal antigen detection test. Cultures reported GAS whereas molecular testing reported GAS, GCS, and GGS. We performed a retrospective chart review to examine the epidemiological differences of GAS, GCS, and GGS pharyngitis. Methods Records were obtained of pharyngeal samples from patients sent for testing at Beaumont Health Laboratory. In all, 92,369 records were analyzed. There were 47,106 records of cultures from May 2012 through December 2014 and 45,263 records of molecular testing from May 2015 to December 2017. Samples positive for either GCS or GGS were reported as positive for Group CG Streptococcus (GCGS). Epidemiological factors were evaluated. If available, electronic records from GCGS positive samples were evaluated for clinical features, antibiotics used, and sequelae or complications reported. Results Molecular testing showed GAS positivity of 9.3% (n = 4,189) and GCGS positivity of 1.5% (n = 687). GCGS pharyngitis was more likely during the summer months and in young adults 13 years and older than children under 13 years. GAS pharyngitis was more likely during spring months and in children aged 4–9 years. Mean age of GCGS pharyngitis was 13 vs. 8.6 years for GAS pharyngitis. Similar results were obtained for GAS between culture and molecular testing records. Amoxicillin was most often prescribed for treatment of GCGS. There were few instances of severe GCGS exudative or recurrent pharyngitis that required hospitalization or tonsillectomy. There were no cases of rheumatic fever or rheumatic heart disease associated with GCGS. Conclusion This is the largest study based on our literature review to evaluate the epidemiology of GAS, GCS, and GGS pharyngitis in children and adults. We found a seasonal and age difference between GAS and GCGS. Complications were rare, and no rheumatogenic sequelae were noted from GCGS infections. Disclosures All Authors: No reported Disclosures.


2017 ◽  
Vol 39 (19) ◽  
pp. 151-157 ◽  
Author(s):  
Jennifer Woo ◽  
Valerie Arboleda ◽  
Omai B. Garner

Author(s):  
Carla Penney ◽  
Robert Porter ◽  
Mary O’Brien ◽  
Peter Daley

Background. Acute pharyngitis caused by Group AStreptococcus(GAS) is a common presentation to pediatric emergency departments (ED). Diagnosis with conventional throat culture requires 18–24 hours, which prevents point-of-care treatment decisions. Rapid antigen detection tests (RADT) are faster, but previous reports demonstrate significant operator influence on performance.Objective. To measure operator influence on the diagnostic accuracy of a RADT when performed by pediatric ED nurses and clinical microbiology laboratory technologists, using conventional culture as the reference standard.Methods. Children presenting to a pediatric ED with suspected acute pharyngitis were recruited. Three pharyngeal swabs were collected at once. One swab was used to perform the RADT in the ED, and two were sent to the clinical microbiology laboratory for RADT and conventional culture testing.Results. The RADT when performed by technologists compared to nurses had a 5.1% increased sensitivity (81.4% versus 76.3%) (p=0.791) (95% CI for difference between technologists and nurses = −11% to +21%) but similar specificity (97.7% versus 96.6%).Conclusion. The performance of the RADT was similar between technologists and ED nurses, although adequate power was not achieved. RADT may be employed in the ED without clinically significant loss of sensitivity.


2016 ◽  
Vol 28 (2) ◽  
pp. 199-204 ◽  
Author(s):  
Ulrich Orda ◽  
Biswadev Mitra ◽  
Sabine Orda ◽  
Mark Fitzgerald ◽  
Ronny Gunnarsson ◽  
...  

2001 ◽  
Vol 125 (10) ◽  
pp. 1307-1315 ◽  
Author(s):  
Gerald J. Kost

Abstract Objective.—To prevent medical errors, improve user performance, and enhance the quality, safety, and connectivity (bidirectional communication) of point-of-care testing. Participants.—Group A included 37 multidisciplinary experts in point-of-care testing programs in critical care and other hospital disciplines. Group B included 175 professional point-of-care managers, specialists, clinicians, and researchers. The total number of participants equaled 212. Evidence.—This study followed a systems approach. Expert specifications for prevention of medical errors were incorporated into the designs of security, validation, performance, and emergency systems. Additional safeguards need to be implemented through instrument software options and point-of-care coordinators. Connectivity will be facilitated by standards that eliminate deficiencies in instrument communication and device compatibility. Assessment of control features on handheld, portable, and transportable point-of-care instruments shows that current error reduction features lag behind needs. Consensus Process.—Step 1: United States national survey and collation of group A expert requirements for security, validation, and performance. Step 2: Design of parallel systems for these functions. Step 3: Written critique and improvement of the error-prevention systems during 4 successive presentations to group B participants over 9 months until system designs stabilized into final consensus form. Conclusions.—The consensus process produced 6 conclusions for preventing medical errors in point-of-care testing: (1) adopt operator certification and validation in point-of-care testing programs; (2) implement security, validation, performance, and emergency systems on existing and new devices; (3) require flexible, user-defined error-prevention system options on instruments as a prerequisite to federal licensing of new diagnostic tests and devices; (4) integrate connectivity standards for bidirectional information exchange; (5) preserve fast therapeutic turnaround time of point-of-care test results; and (6) monitor invalid use, operator competence, quality compliance, and other performance improvement indices to reduce errors, thereby focusing on patient outcomes. (Arch Pathol Lab Med. 2001;1307–1315)


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