Evaluation of middle ear fluid in acute otitis media with Gram-stained smear.

Abstract

To The Editors: It was interesting to read the report by Broides et al. 1 We have decided to share the results of a study we performed. In that study we investigated the sensitivity and specificity of observed bacteria and leukocytes in Gram-stained smears of middle ear fluid (MEF) to determine whether the causative agent was bacterial in cases of acute otitis media (AOM). During the study 92 MEF samples from 79 patients diagnosed as AOM were analyzed. Seventy-nine of the 92 samples were obtained before treatment was given. The remaining 13 samples were from children who had failed treatment for AOM. In 45 of 79 cases we found positive bacterial culture results. We evaluated 48 MEFs of the 45 patients who had positive cultures, and in the culture-negative group, consisting of 34 patients, we tested 44 MEFs. In all MEF samples with positive culture results, either Gram-positive or Gram-negative bacteria were seen. In the group with negative culture results, only two samples showed bacteria on Gram-stained smear (sensitivity 96%, specificity 100%). Similarly all samples with positive bacterial culture results had leukocytes. In the culture-negative group leukocytes were seen in 93% (sensitivity 53%, specificity 100%). For children who are candidates for tympanocentesis but for whom culture will not be performed because of financial or technical reasons, Gram stain of MEF is a cheap and reliable method for deciding whether the causative agent is a bacterium and whether there is an indication for antibiotic use. This method also saves time necessary for obtaining culture results. Fatma Oğuz, M.D. Emin Ünüvar, M.D. Gülnur Dündar, M.D.