Middle Ear Effusion Interleukin-6 and Interleukin-8 levels could Differentiate between Bacterial and Non-Bacterial Acute Otitis Media and Help to Identify the Type of Infecting Bacteria

This study aimed to investigate the middle ear effusion (MEE) levels of interleukin-6
(IL-6) and IL-8 inchildren with acute otitis media (AOM) and their relation to its
etiology and type of infecting bacteria as a trial to define a faster diagnostic modality
than traditional culture and sensitivity testso as to early initiate therapy. The study
included 70 children; 44 males and 26 females, with a mean age of 19.3±8 months;
50 patients had unilateral and 20 bilateral AOM (n=90 ears). The diagnosis of AOM
was based on presence of fever, irritabilityor earache and signs of inflammation of
thetympanic membrane. The presence of MEE was documented by tympanocentesis
and MEE sampleswere obtained for culture to define the offending pathogen,
cytological examination to grade it according to number of polymophonuclear
leucocytes (PNL) and ELISA estimation of the levels of IL-6 and IL-8. Sensitivity and
specificity of MEE IL-6 and IL-8 levels for differentiation between bacterial and non-bacterial cases and identification of infecting bacteria were evaluated using the
receiver operating characteristic (ROC) curve analysis judged by the area under the
curve (AUC). Bacteriological examination identified the infective pathogen in 61
samples (67.7%) and no bacterial infection in 29 samples (32.3%). Combined
infection with Haemophilus influenzae (H. inf.) and Streptococcus pneumoniae (S.
pn.) was detected in 12 samples. However, single pathogen infection was detected in
49 samples; H. inf in 35 samples, S. pn in 11 samples, Moraxella catarrhalis in 2
samples and S. pyogenes in one sample. Effusion was serous in 52, mucoid in 28 and
purulent in 10 effusions. Nine samples weregrade I, 35 were grade II, 29 samples
were grade III and 17 samples were grade IV. There was a significant (p<0.05)
increase of MEE IL-6 level in samples withpositive culture compared to samples with
negative culture. Also, there was a significant(p<0.05) increase in MEE IL-6 levels
in samples positive for S. pn. compared to its levels estimatedin samples infected with
H. inf. or by both pathogens. Mean MEE IL-8 level was significantly (p<0.05)
elevated in samples with positive culture compared to levels estimated in samples
with negative culture. Moreover, MEE IL-8 levels in samples positive for H. inf. were
significantly (p<0.05) elevated compared to levels estimatedin samples positive for S.
pn. and non-significantly (p>0.05) elevated compared to levels estimated in samples
with mixed infection. ROC curve analysis revealed that estimation of MEE levels of
both IL-6 and IL-8 are specific for the presence of bacterial AOM with AUC=0.832 &
0.897, respectively. Elevated MEE level of IL-6 could differentiate between H. inf.
and S. pn. infection with high specificity with AUC=0.758, while IL-8 was more
sensitive indictor of H. inf. infection with AUC=0.363. It may be concluded that AOM
is associated with elevated MEE levels ofIL-6 and IL-8 which may suggest a role
imposed by these cytokines in pathogenesis of AOM. The elevated levels of both
cytokines could differentiate bacterial from non-bacterial cases with high specificity.
Elevated MEE level of IL-6 may be specific for S. pn infection, while elevated IL-8
levels may be a sensitive for H. inf. infection