Dynamics of interleukin-1 production in middle ear fluid during acute otitis media treated with antibiotics

In an ongoing prospective study IL-1 concentrations mere measured in 78 children (aged 3-36 months) with acute otitis media receiving antibiotics. Middle ear fluid IL-1 concentrations were determined using ELISA kits. Ninety-eight middle ear fluid samples were obtained by tympanocentesis at enrollment (day 1) and 43 samples mere collected on days 4-5, Ninety-two pathogens were isolated in 77/98 samples obtained on day 1: 55 Haemophilus influenzae, 34 Streptococcus pneumoniae, 2 Moraxella catarrhalis and 1 Streptococcus pyogenes. Among 37 paired samples initially culture-positive, eradication of the pathogen was achieved on day 4-5 in 20 while pathogens mere still present in 17, On day 1, IL-1 was detected in 61/77 (79%) culture-positive samples vs 9/21 (43%) culture-negative ones (P = 0.003), The mean +/- SD middle ear fluid concentration of IL-1 on day 1 was significantly higher in culture-positive (316 +/- 508 pg/ml) than in culture-negative samples (111 +/- 245 pg/ml) (P = 0.01), When paired samples were evaluated, IL-1 decreased on days 4-5 in 13/20 (65%) ears where bacterial eradication was achieved,but also in 11/19 (58%) with persistent or new infection. The mean IL-1 concentrations decreased on days 4-5 in the 20 samples from ears where bacterial eradication was achieved (330 +/- 460 vs 118 +/- 294 pg/ml, P = 0.1) but also in the 17 samples where it was not (465 +/- 660 vs 232 +/- 289 pg/ml, P = 0.2), No significant differences were found between day 1 and days 4-5 in the mean IL-1 concentrations measured in patients with H, influenzae vs S, pneumoniae or concomitant H, influenzae and S, pneumoniae, It was concluded that: 1) IL-1 mas detected in the middle ear fluid of most patients with acute otitis media; 2) significantly higher IL-1 concentrations were found in patients with culture-positive than in those with culture-negative acute otits media; 3) IL-1 concentrations decreased on days 4-5 of antibiotic therapy whether the pathogen was eradicated or not.