Study of β-Haemolytic Streptococci among Pharyngitis Cases Visiting Bir Hospital

Abstract

Pharyngitis is commonly encountered upper respiratory tract illnesses for which patients seek medical advice. The purpose of this study was to analyze the underlying bacterial pathogens in pharyngitis cases. During study period February 2010 to August, 2010, a total of 134 patients visiting E.N.T. OPD of Bir hospital complaining sore throat were studied. Throat swabs collected were cultured to 5.0% blood agar plate and incubated at 37 0 C of 24-48 hrs, clear transparent β-haemolytic colonies were selected and identified. Group A streptococcus (GAS) was identified by βhaemolytic colonies with Bacitracin and Penicillin sensitivity, Gram staining, catalase negativity and growth on crystal violet blood agar (CVBA). In this study 23 (17.2%, 23/134) of patients were positive for β-haemolytic streptococci (BHS), among them 12 (9%) were identified as GAS. The prevalence of culture positive for BHS was highest (56.5%, 13/23) among the age group of 21-40 years. Antibiotic susceptibility test for isolates was done by using modified Kirby-Bauer disk diffusion method. Pathogens other than BHS were isolated from 9 patients, of which 4 cases showed mixed bacterial growth i.e. 14 bacterial isolates from 9 cases. Other bacterial isolates reported in the study were Staphylococcus aureus 6 (4.5%), Klebsiella pneumoniae 5 (3.7%), Pseudomonas aeruginosa 2 (1.5%), Citrobacter freundii 1 (0.7%), and yeast cells 1 (0.7%). It was found that infections caused by β-haemolytic streptococci is significantly higher P=0.0084 i.e. (P<0.05) than infections caused by other bacteria. This study demonstrated that young adults of age group 21-40 were affected by streptococcal pharyngitis. The isolates of GAS were 100% sensitive to Amoxycillin, Cephalexin, Cefotaxime, Ciprofloxacin and Azithromycin followed by Cotrimoxazole (91.7%) and Erythromycin (91.7%). Key words: β-haemolytic streptococci, BHS, Bir hospital, GAS, Pharyngitis, Sore throat