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Is Streptococcus pyogenes a pathogen or passenger in uncomplicated acute sore throat? A systematic review and
Patrycja Woldan-Gradalska1, Wojciech Gradalski2, Ronny K Gunnarsson3
1General Practice/Family Medicine, School of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Research, Education, Development & Innovation, Primary Health Care, Region Västra Götaland, Borås, Sweden; Centre for Antibiotic Resistance Research (CARe) at University of Gothenburg, Gothenburg, Sweden; Sätila Primary Health Care Centre, Sätila, Sweden.
Objectives:
The objective was to estimate the probability that finding a Streptococcus pyogenes (Group A Streptococcus) in a throat swab in a patient with a sore throat reflects the aetiology. We also investigated to what extent this is influenced by age, carrier rates of S. pyogenes and climate zone.
Methods:
We conducted a comprehensive search of Medline and Scopus up until October 2023 for case-control studies reporting the prevalence of S. pyogenes in patients with a sore throat and healthy controls. We only included studies with separate data for children and adults. We used the positive and negative etiologic predictive values (P-EPV and N-EPV) to estimate the probability of a link between a sore throat and a finding of S. pyogenes.
Results:
We included 15 studies in our meta-analysis. The overall P-EPV for children and adults were 63% (49-74%) and 92% (87-95%), respectively. The P-EPV rose to 83% (64-93%) for children and 94% (90-97%) for adults when only patients with 3-4 Centor criteria were included. The overall N-EPV was 97% (96-98%) for children and 96% (95-97%) for adults.
Conclusion:
Detecting S. pyogenes in adult patients with an uncomplicated acute sore throat is useful to rule in S. pyogenes as the likely aetiologic agent. The P-EPV significantly increased for children when those with 3-4 Centor criteria were selected. A negative throat swab is always useful for both children and adults to rule out S. pyogenes as the cause of sore throat.
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