BACKGROUND: Limited information is available on the cellular characteristics of the middle ear fluid (MEF) during acute otitis media (AOM). OBJECTIVES: To determine the white blood cell (WBC) composition of the MEF in AOM before and during antibiotic therapy. MATERIALS AND METHODS: Total WBC and differential counts were determined in the MEF of 96 infants and children (ages 2 weeks to 3 years) with AOM who were receiving antibiotics. WBC counts were reported as number of WBC/mg MEF (mean +/- sd). RESULTS: One hundred forty-five MEF samples were obtained by tympanocentesis at enrollment (Day 1), and 36 samples were collected on Days 4 to 5 after initiation of antibiotic therapy. Sixty-one percent of the patients were <1 year of age, and 38% were receiving antibiotic therapy at enrollment. Twenty-eight MEF samples were paired (same ear, Day 1 and Days 4 to 5). One hundred twelve pathogens were isolated from 95 of 145 (66%) culture-positive samples obtained on Day 1: 67 Haemophilus influenzae, 40 Streptococcus pneumoniae and 5 others. MEF WBC counts were lower on Day 1 in patients who had received previous antibiotic therapy than in those who had not (432.4+/- 412.8 vs. 590.5 +/- 436.8, P = 0.03). WBC counts were higher on Day 1 in culture-positive than in culture-negative samples (603.9 +/- 504.9 vs.421.4 +/- 373.4, P = 0.02). WBC counts were higher on Day 1 in MEF samples positive for S. pneumoniae than in those positive for H. influenzae (799.2 +/- 641.5 vs.506.4 +/- 401.9, P = 0.04). There were no differences in the number of neutrophil WBC present in the samples obtained on Day 1 vs. Days 4 to 5 or between samples positive vs.samples negative for bacterial pathogens. CONCLUSIONS: WBC counts were higher in the MEF of patients with culture-positive AOM than in those with culture-negative AOM and in those with AOM caused by S. pneumoniae.
BACKGROUND: Limited information is available on the cellular characteristics of the middle ear fluid (MEF) during acute otitis media (AOM). OBJECTIVES: To determine the white blood cell (WBC) composition of the MEF in AOM before and during antibiotic therapy. MATERIALS AND METHODS: Total WBC and differential counts were determined in the MEF of 96 infants and children (ages 2 weeks to 3 years) with AOM who were receiving antibiotics. WBC counts were reported as number of WBC/mg MEF (mean +/- sd). RESULTS: One hundred forty-five MEF samples were obtained by tympanocentesis at enrollment (Day 1), and 36 samples were collected on Days 4 to 5 after initiation of antibiotic therapy. Sixty-one percent of the patients were <1 year of age, and 38% were receiving antibiotic therapy at enrollment. Twenty-eight MEF samples were paired (same ear, Day 1 and Days 4 to 5). One hundred twelve pathogens were isolated from 95 of 145 (66%) culture-positive samples obtained on Day 1: 67 Haemophilus influenzae, 40 Streptococcus pneumoniae and 5 others. MEF WBC counts were lower on Day 1 in patients who had received previous antibiotic therapy than in those who had not (432.4+/- 412.8 vs. 590.5 +/- 436.8, P = 0.03). WBC counts were higher on Day 1 in culture-positive than in culture-negative samples (603.9 +/- 504.9 vs.421.4 +/- 373.4, P = 0.02). WBC counts were higher on Day 1 in MEF samples positive for S. pneumoniae than in those positive for H. influenzae (799.2 +/- 641.5 vs.506.4 +/- 401.9, P = 0.04). There were no differences in the number of neutrophil WBC present in the samples obtained on Day 1 vs. Days 4 to 5 or between samples positive vs.samples negative for bacterial pathogens. CONCLUSIONS: WBC counts were higher in the MEF of patients with culture-positive AOM than in those with culture-negative AOM and in those with AOM caused by S. pneumoniae.