Could fungi be detected in the fluid of persistent otitis media with effusion?

Background Otitis media with effusion (OME) often is considered a direct extension of the inflammatory process that occurs during long-lasting or recurrent episodes of acute otitis media. The observations above suggest that OME has an infectious etiology. Most bacterial and viral cultures of middle ear fluid that had been performed were often negative suggesting that other infectious agents may be involved such as fungi. Materials and methods Thirty patients (group A) suffering from chronic secretory otitis media (OME) were enrolled in this study. Three samples were collected and investigated using PCR assay with universal fungal primers and Sabouraud agar. The first sample was obtained from the fluid of the middle ear before insertion of the ventilation tube; the second sample was obtained from nasal secretions; and the third sample was obtained from the ipsilateral peritubal area of the nasopharynx. Thirty patients (group B) with comparable age group without history of ear diseases scheduled for tonsillectomy or adenotonsillectomy were added as a control group. Samples from peritubal area of the nasopharynx of patients and nasal secretion were tested using PCR assay with universal fungal primers and Sabouraud agar. Results PCR examination of the middle ear aspirate in group (A) cases was positive in 7 cases (23.3%), in nasal secretions samples 2 cases only (13.3%) were positive and no positive cases were detected in nasopharyngeal swab samples. In group (A), Sabouraud agar culture was positive for fungal culture of middle ear aspirates in 5 cases (16.6%) but in no cases for nasal secretion samples. Group A showed also negative (N 0 ) growth in 30 (100%) patients for nasopharyngeal swab on Sabouraud agar. In group B, the findings of nasopharyngeal swab were negative (N 0 ) growth in all examined samples on Sabouraud agar, and nasal secretions were also negative for fungal DNA detection using PCR assay. Conclusion In this study, fungal DNA could be detected in the middle ear fluid in seven (23.3%) of 30 patients with persistent OME using PCR assay, and fungi could be detected in five (16.6%) patients on Sabouraud agar. A significant relationship was found between detection of fungi in the middle ear fluid and the duration of the disease, associated adenoid, and history of asthma.


Introduction
Otitis media with effusion (OME) often is considered a direct extension of the inflammatory process that occurs during long-lasting or recurrent episodes of acute otitis media. The observations suggest that OME has an infectious etiology. Most bacterial and viral cultures of middle ear fluid that had been performed were often negative suggesting that other infectious agents may be involved such as fungi (Bluestone CD;et al,1988). The diagnosis of fungal infection as an etiological factor in pathogenesis of most diseases is a significant problem. Fungal routine diagnostic tests including culture and histopathological examinations have been limited sensitivity and specificity. PCR showed to be useful molecular techniques for detection of pathogens particularly for detection of those with slowly growing (Kim EJ;et al,2002)

Materials and Methods
Thirty patients suffering from chronic secretory otitis media were enrolled in this study (group A). Inclusion criteria (1) Age range from 4 to 15 years.
(2) Unilateral or bilateral OME of at least 3 months duration.
(4) History of asthma or chronic respiratory tract infection. Exclusion criteria (1) No history of ear discharge.
(2) No history of middle ear surgery before enrollment of the patient in the study.
(3) No active middle ear inflammation at the time of middle ear fluid aspiration.
Three samples were collected and investigated using PCR assay with universal fungal primers and Sabouraud agar. The first sample was obtained from the fluid of the middle ear before insertion of the ventilation tube; the second sample was obtained from nasal secretions; and the third sample was obtained from the ipsilateral peritubal area of the nasopharynx. Thirty patients (group B) with comparable age group without history of ear diseases scheduled for tonsillectomy or adenotonsillectomy were added as a control group. Samples from peritubal area of the nasopharynx of patients and nasal secretion were tested using PCR assay with universal fungal primers and Sabouraud agar.
PCR analysis was performed using specific pan-fungal primers(universal fungal primers) on the isolated DNA molecules from middle ear effusion samples.

Conclusion
In this study, fungal DNA could be detected in the middle ear fluid in seven (23.3%) patients of 30 patients with persistent OME using PCR assay, and fungi could be detected in five (16.6%) patients on Sabouraud agar. The results of this study according to statistical analysis demonstrated significant relationship between detection of fungi in the middle ear fluid and the duration of the disease, associated adenoid, and history of asthma. This study high lighted the possibility that fungi detected in the fluid of the middle ear can be considered as one of the etiological factors in the pathogenesis of chronic OME.

Results
PCR examination of the middle ear aspirate in group (A) cases was positive in 7 cases (23.3%), in nasal secretions samples 2 cases only (13.3%) were positive and no positive cases were detected in nasopharyngeal swab samples. In group (A), Sabouraud agar culture was positive for fungal culture of middle ear aspirates in 5 cases (16.6%) but in no cases for nasal secretion samples Group A showed also negative (N0) growth in 30 (100%) patients for nasopharyngeal swab on Sabouraud agar. In group B, the findings of nasopharyngeal swab and nasal secretions were negative (N0) growth in all examined samples on Sabouraud agar and negative for fungal DNA detection using PCR assay. The results showed that there was high statistically difference between middle ear effusion PCR results among asthmatic and non-asthmatic and among adenoids and non-adenoids with p-value <0.05 .