Prevalence of Group A Beta-Hemolytic Streptococcus Oropharyngeal Colonization in Children and Therapeutic Regimen Based on Antistreptolysin Levels: Data from a City From Southern Brazil

Abstract

The aim of this study is to determinate the prevalence of oropharyngeal colonization by group A beta-hemolytic Streptococcus (GABHS) in pediatric population of Ponta Grossa, a midsize city of southern Brazil; estimate the effectiveness of antistreptolysin-O (ASO), compared to culture, in presence of infection; and design an unpublished investigative algorithm of rheumatic fever's suspicion, based on needs identified in worldwide consensus. It is an epidemiologic, observational and transversal study, involving 180 children younger than 12 years. Secretion of posterior oropharynx was collected for culture; and peripheral blood for determination of ASO. Student-t and chi-square tests, with Yates correction, were performed for statistical analysis. The ASO cutoff was determined by Receiver Operating Characteristic (ROC) curve. The prevalence encountered was 3.9%, and 25.5% of the children showed reagent ASO. This serological test demonstrated quantitatively and qualitatively significant associations to the GABHS presence (p=0.0001 for both associations) throughout the ROC curve, 200 U Todd was the value that resulted in the best accuracy, demonstrating 100% of sensibility and 80% of specificity in the GAS infection documentation. Also, it was found that the value of 1.200 U represents a specificity of 100%. The results emphasize the need for similar studies in other populations, to provide better targeting of the diagnosis and treatment of oropharyngitis by GABHS, which in turn can prevent up to 80% the cases of rheumatic fever, and consequently, the chronic rheumatic heart disease.

Differences in gram-positive bacterial colonization and antimicrobial resistance among children in a high income inequality setting

“…BHS colonization frequency was low (4%), similar to another study conducted in southern Brazil (5.6%) [35]. However, the small sample size limited our ability to investigate differences in colonization and risk factors by SES.…”

“…MRSA colonization among all SES groups (8.1%) in Niterói was higher than frequencies observed in high-income populations (≤ 1%), such as in USA, Canada, northern Europe, and Hong Kong [28]. However, the difference in colonization prevalence between high and low SES groups observed in the present study (6% vs. 14%) reflects differences in prevalence among children from these high-income populations compared with 6–29% in populations from LMICs, such as Iran, Botswana, Angola, India [29–31, 33, 35], and public childcare centers in Brazil [22, 34].…”

Group A Streptococcus pharyngitis and pharyngeal carriage: A meta-analysis

“…[ 24 ] When throat culture alone is used to diagnose GAS pharyngitis, many patients prescribed antibiotics are likely suffering viral pharyngitis with coincidental GAS carriage. [ 25 – 27 ] The reference standard for determining whether true GAS pharyngitis is present requires both throat culture and serological testing to identify GAS+ve patients with elevated antibodies targeting conserved GAS antigens, streptolysin-O and deoxyribonuclease-B. [ 28 , 29 ] However, serological testing relies on obtaining patient blood samples and thus is not routinely performed in primary care.…”

Acute rheumatic fever in children: Experience at the hospital Hassan II of Fez, Morocco

“…This raised levels of antistreptococcal antibodies are not specific only for beta-hemolytic streptococcus group A, but can also be seen during infections caused by other types of streptococci such as streptococcus group C and G, which do not lead to ARF. 30 Throat culture for Group A beta-hemolytic streptococci are not realized in our study.…”