A comparative study of isolation, identification and grouping of streptococcal isolates from throat swabs of school going children applying different methods of extraction for antigen

Abstract

Objective: The objective of this research was to collect the throat swabs from symptomatic and asymptomatic children and microbiologically positive sample were further taken up for grouping. Methods: Extraction of streptococcal group antigen by various methods namely enzyme extraction, fullers extraction, Lancefield extraction. Comparing the antigen extraction methods in identifying the sero groups of BHS.Comparative studies between conventional and enzymatic methods of extraction. Which one is ideal method of extraction and which one is common among the children. Results: Throat swabs were collected in the age group of 5-12 both symptomatic and asymptomatic children. Symptomatic such as rashes, throat pain, fever, cold, cough etc. Totally 361 throat swabs were collected of which 19 were BHS.18 isolates were typeable and 1 was non typeable. In enzyme extraction is not effective in the extraction of group D streptococci may be extracted with mutanolysin only after 4H incubation although effective for the extraction of some strains of group D streptococci.in fullers extraction it was seen to give an important clue to the structure of cell wall of gram positive bacteria in lance field extraction was easily performed specific and sensitive method. Conclusion: Group A streptococcal isolates were just 2 in no which shows that group A is not the predominant strain in our study. There by denoting the prevalence of rheumatic fever and RHD are becoming less. There was no cross reaction among groups were lancefield and fullers method were applied.in enzymatic method there was slight cross reaction noted between A and D in one isolate,F and G in one isolate and C and G in another isolate.