Frequency and Resistance Patterns of Streptococcus Pneumoniae in Acute Otitis Media

Background and Acute otitis media (AOM) remains a frequent global infection of childhood, with up to 80% of children having at least one episode by three years of age. Ten to 30% have recurrent episodes, and 2–25% will have persistent middle ear effusion extending beyond three months. This study was conducted to determine the prevalence of Streptococcus pneumoniae in patients with acute middle ear infections and determine the antibiotic susceptibility patterns of this microorganism. In total 102 middle ear discharge specimens were collected during 6 months period from patients with acute otitis media attending Amir Alam Hospital, affiliated to Tehran University of Medical Sciences. The inclusion criteria included: perforated acute otitis media diagnosed by a physician and not taking any antibiotic in recent two weeks. Specimens were assessed for Streptococcus pneumoniae by microscopic examination and culture. The antibiotic susceptibility test was done by disk diffusion method of Kirby-Bauer and sensitivity frequency of tested antibiotics was assessed by appraisal diameter of the growth inhibitory zone. Of 102 tested specimens, 15 (eight males and seven females, 14.7%) were recognized as Streptococcus pneumonia. The sensitivity of isolated Streptococcus pneumoniae to different antibiotics included gentamicin (86%), kanamycin (80%), amikacin (74%), tetracycline (73%), and colistin (73%). The resistance patterns were seen in penicillin (80%), amoxicillin (80%), cephalotin (73%), erythromycin (65%), ampicillin (65%), nalidixic acid (60%), nitrofurantoin (60 %), vancomycin (53%), chloramphenicol (53%), and carbenicillin (53%). According to the emergence of resistant strains of Streptococcus pneumoniae to conventional antibiotic therapy, especially beta-lactam antibiotics and erythromycin, it is recommended to perform further studies to determine full picture of antibiotic susceptibility in circulating Streptococcus pneumonia in patients with AOM to revise existing guidelines of empirical therapy of AOM in Iran.