Thesis (M.Sc.) - Cairo University - Faculty of Pharmacy - Department of Microbiology and Immunology

Chronic suppurative otitis media (CSOM) is a recurrent or chronic infection of the ear, prevalent worldwide especially among the poor populations in developing countries, the infection is characterized by mucopurulent otorrhea through a perforated tympanic membrane and may end in hearing loss. Total of 80 bacterial strains were isolated from ear discharges of clinically diagnosed CSOM patients in two Egyptian hospitals. The isolates were identified using traditional methods along with the API® system. Percentages of different isolates obtained were about 58% Staphylococcus, 21% Pseudomonas, 20% Proteus and 1% Klebsiella. The isolates were screened for biofilm formation and antibiotic resistance, in addition to the complement resistance ability in Gram negative bacterial isolates. The probable correlations between the three studied factors were also investigated. Antibiotic susceptibility testing showed that about 54% of the isolates were multidrug resistant, the biofilm assay showed that about 20% of the isolates were biofilm forming, while the complement resistance existed in about 68% of the tested Gram negative bacteria. Methicillin resistant S. aureus (MRSA) represented the most common isolate of about (38%), accordingly the mecA gene and the dltB gene (biofilm formation-regulating gene) were screened using PCR technique, and this showed that 75% of the screened S. aureus isolates yielded positive mecA gene while 100% of the screened S. aureus isolates yielded dltB gene

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