Prevalence and antibiotic susceptibility of group A beta-haemolytic streptococcal isolates in children presenting with acute pharyngitis in Lusaka, Zambia

Background. Group A beta-haemolytic streptococci (GABHS)-associated pharyngitis can complicate into rheumatic fever and rheumatic heart disease (RHD).Objectives. To determine the prevalence and antibiotic susceptibility of GABHS isolates in children presenting with acute pharyngitis and assess the utility of Zambian Treatment Guideline (ZTG) criteria as a local clinical scoring system.Methods. This descriptive cross-sectional study was conducted at the paediatric outpatient department of the University Teaching Hospital in Lusaka, Zambia. The study cohort, comprising children aged 3 - 15 years (n=146), were recruited as presenting with symptoms of pharyngitis. The children underwent a clinical assessment that included a detailed case history, presenting symptoms and a throat swab that was subsequently cultured. Microbial isolates were typed and the antibiotic sensitivity of cultured GABHS to penicillin and erythromycin determined.Results. GABHS were cultured from 22 (15.1%) children within this study. All the GABHS isolates (n=22) were susceptible to penicillin G; however, 19% of isolates displayed reduced susceptibility to erythromycin. None of the ZTG criteria, when used individually, was sufficiently sensitive to detect GABHS pharyngitis among this cohort.Conclusion. The prevalence of GABHS pharyngitis is similar that been described elsewhere. While GABHS remains highly susceptible to penicillin, which is used in the local RHD control programmes, concern remains for children treated with erythromycin owing to the resistance noted in some of the isolates. The ZTG clinical criteria displayed poor sensitivity in identifying GABHS pharyngitis. This has significant implications for effective diagnosis and treatment of pharyngitis and associated complications within this high RHD endemic area

Pertussis An update for general practice

Although there has been a global decline in the incidence of pertussis in the past four decades; the incidence has increased in developed countries; particularly in preteens; adolescents and adults. These groups provide a major reservoir of the disease for vulnerable unimmunised or incompletely immunised infants. This trend has not yet been documented in South Africa. In young infants; the diagnosis is made on the basis of clinical features. Older age groups do not usually show the typical clinical picture; leading to misdiagnosis and underreporting. The culture of Bordetella pertussis from the posterior nasopharynx remains the gold standard for diagnosis but laboratory diagnosis is complex and unavailable in most settings. Erythromycin; instituted early in the course of illness; remains the treatment of choice although there is now good evidence for the use of other macrolides; particularly in the neonate. Immunisation of young infants remains the best preventative methodagainst the disease. Due to the re-emergence of the disease in older age groups; developed countries are recommending booster vaccines in adolescents