Bacteriology and antibiotic susceptibility pattern of peritonsillar abscess.

INTRODUCTION: Peritonsillar abscess is a common complication of acute tonsillitis. Its management consists of aspiration or surgical drainage followed by appropriate antibiotics. Appropriate antibiotic treatment depends on the common organisms associated with infection and their antibiotic sensitivity pattern in local scenario.
METHODS: Pus samples aspirated from diagnosed cases of peritonsillar abscess and submitted for culture and sensitivity in last two years were included in this study. Identification of different microorganisms was made on the basis of the microscopic findings, observation of their colony morphology and standard biochemical reactions. Susceptibility pattern to commonly used antibiotics were determined by Clinical Laboratory Standards Institute (CLSI) guidelines.
RESULTS: Altogether 24 pus samples were included in the study. Positive culture was obtained from 18 samples. Among them one organism was isolated from 13 samples whereas from five samples multiple organisms were isolated. From six samples no organisms could be cultured. Altogether Streptococcus pyogenes was isolated from 12 samples and Staphylococcus aureus from five samples. Other isolated organisms included Haemophlilus influenzae, Pseudomonas aeruginosa, Escherichia coli and Enterococcus species. Penicillin was effective for Streptococcus pyogenes whereas Staphylococcus aureus was resistant to it. Cloxacillin was found to be effective for Staphylococcus aureus. Ciprofloxacin and Ceftazidime were found to be effective for both organisms.
CONCLUSIONS: Streptococcus pyogenes and Staphylococcus aureus were more commonly associated with peritonsillar abscess. Streptococcus pyogenes were sensitive to penicillin but all Staphylococcus aureus were resistant to it. This fact should be considered in clinical practice for management of peritonsillar abscess.