Assessment of beta haemolytic streptococci carriage among school children in Calabar, Nigeria- A brief study

Abstract

Colonization of the upper respiratory tract of children by beta-haemolytic streptococci (BHS) is imperative in spreading the infection in households and in community settings. The present study was designed to investigate the prevalence of throat carriage of diverse antigenic groups of BHS and the influence of age on carrier rates in healthy children in Calabar. Throat swabs of 450 children's were taken randomly from some government and private elementary schools and were visually examined and collected for further investigations.. The swabs were cultured aerobically on goat blood agar. Antimicrobial sensitivity testing was carried out on all BHS isolates on Muller Hinton blood agar by using the Kirby-Bauer disc diffusion method after standardizing the inoculums with a 0.5 McFarland. A total of 18(4%) BHS pharyngeal carriers were detected. BHS belonging to four streptococcal groups were isolated, groups C, F and G. The fourth group was not identified by the available grouping kit (UID S). Group C streptococci (GCS) had the highest percentage carriage of 5/18(27.8%). Other groups were F 3/18(16.7%), G 2/18(11.2%) and the UID S 8/18(44.4%). Carrier rate increased as age group increased and peaked at age group 10-12 years 7(36.8%). The percentage of BHS pharyngeal carriage was higher in Government aided schools (6.7%) than in private schools (1.7%). The BHS were highly resistant to Penicillin and Ceftazidime with a resistivity rate of 94.7% while Augmentine showed the lowest resistivity rate of 15.8%. The study established a high carriage of diverse antigenic groups in the throat of children with age influencing the rate of carriage in this community. A throat carrier rate of 39% of GGS/GCS among 450 children from this population indicated the etiological importance of streptococcal pharyngitis in this population. Therefore, there is need for further studies to identify the specific serotype of the group C/G streptococci circulating in this community.