Group a streptococcal infection among children with Pharyngitis in jimma town, southwest ethiopia

Abstract

Background: Group A Streptococcus (GAS) is an important cause of morbidity and mortality with clinical presentation ranges from pharyngitis and pyodrema, to life threatening immunological complications such as acute rheumatic fever and glomerulonephritis. GAS is the most common cause of bacterial pharyngitis responsible for 20–30% in children and 5 – 15% in adults. Objective: To determine prevalence, antimicrobial susceptibility pattern and clinical predictors of GAS among children with pharyngitis in Jimma Town Southwest, Ethiopia. Methods: A cross sectional study was conducted on 355 children (5-15 years old) with pharyngitis attended in two selected Health Centers in Jimma town from May 8-December 31, 2013. Demographic and clinical data were collected by using questionnaire and checklist. Throat swabs were collected using sterile cotton swab, inoculated on blood agar plates and incubated for 24-48 hrs at 35-370C with 5% CO2. β- hemolytic colonies that were susceptible for 0.04U bacitracin and pyrrolidonylarylamidase (PYR) positive were considered as GAS. Disc diffusion method was used for antimicrobial sucesbtibility testing for selected antibiotics. McIsaac score was used to determine the diagnostic perfomnance of modified centor score for the diagnosis of GAS. Descriptive statistics and multivariate logistic regression analysis was done by SPSS version 20. P-value less than 0.05 was considered as statistically significant at 95% confidence level. Results: The sex profile of 355 children with pharyngitis showed that about 57.7% were females. Majority (66%) of the children were 5-9 years old giving mean ± SD age of 8.5 ± 2.7II years. The prevalence of GAS was 11.3%. All isolates of GAS were 100% susceptible to penicillin, amoxicillin, erythromycin, clindamycin, chloramphenicol and ceftriaxone but 52.5% were resistant to tetracycline. Absence of cough [AOR 3.77, 95% CI 1.73-8.22], tonsillar swelling or exudate [AOR 4.48, 95% CI 1.63-12.31], temperature >380C [AOR 3.47, 95% CI 1.61-7.49] (p<0.05) were found independent predictors for GAS infection. The sensitivity and specificity of a total McIsaac score ≥ four was 65% and 87.9% respectively compared to culture results. Conclusions: The prevalence of GAS was low. The seasonality of GAS infection may understimate the prevalence in this study, so that large-scale prospective study in the entire season and in various settings is required to understand the actual burden of GAS infection among children’s with pharyngitis. In addition, future studies on children with pharyngitis should focus on estimation of rheumatic heart disease cases that follows from pharyngitis complications. The use of a McIsaac score had a good diagnostic performance to identify GAS infection, which can be considered for the diagnosis in resource-limited settings where culture facilities and rapid antigen tests are not affordable