Microbiology of Chronic Suppurative Otitis Media,Study of the Role of Bacterial Biofilm and Fungal Infection

Abstract

Chronic suppurative otitis media (CSOM) is defined as chronic inflammation of middle ear cleft. The disease is common in all age groups but more prevalent in low socioeconomic group. It is most commonly seen in developing and undeveloped countries affecting 0.5-30% of any community. Local application of antibiotics remains important and first step to get a dry ear. Changes in bacterial flora in last decade and abuse of antibiotics lead to the emergence of multi-drug resistant organisms. Recently, bacterial biofilm are thought to have a major role in much otolaryngologic infection. The formation of biofilm facilitates chronic bacterial infections and reduce efficacy of anti-microbial therapy. It is estimated that biofilm account of approximately 60% of microbial infection in the body. In addition to bacterial biofilm, the role of fungal infections in CSOM needs more attention. Fungal infections of middle ear are common as fungi thrive well in moist pus. There is very little known about mycological aespect of these ears, the importance of which has increasing in the recent years because of the excessive use of broad sepectrum antidiotics, corticosteroids and cytotoxic chemotherapy. Aim: Microbiological examination of chronic suppurative otitis media by detecting bacterial and fungal isolates involved in the infection. Additionally, the detection of the capacity of bacterial biofilm formation. Patients and methods: Forty Patients suffering from chronic suppurative otitis media attending outpatient clinic in Menoufia university hospital and Karmoz insurance hospital were included in this study. Pus discharge was collected using sterile cotton swabs. These samples were cultured for detection of bacterial and fungal infections and Detection of bacterial capability of forming biofilm was done using crystal violet method and by Overnight culture in tryptic Soya Broth (TSB). Results: Most common isolated bacteria were pseudomonas aeurgiosa (37.5%), followed by Klebseilla.spp (10%) and Staph.aeureus (7.5%) and fungal culture gave results to Candida (10%) and Asperigillus (7.5%). Mixed bacterial and fungal infection occurred in (11.7%) of our patients.14 out of 15 cases of pseudomonas infection gave results to biofilm formation(93.3%)and Staph.aeureus infection,3 cases out of 3 cases(100%) were biofilm forming. Conclusion: Routine culture and sensitivity remains the most important step in management of CSOM because of its multi-etiology that makes the empirical therapy impossible. Fungal infection can occur without clinical evidence, therefore, empirical local antifungal therapy is strongly recommended in such cases. Biofilm formation may be responsible for irresponsiveness to antibiotic chemotherapy. Physical removal or inhibition of biofilm may enhance the response to antimicrobial therapy and infection eradication.