الفهرس 
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Abstract
Conclusion and recommendations
This study provided information about the causative agents of CSOM, their antibiotic susceptibility pattern, and their ability to form biofilms in the middle ear cavity causing difficulty in eradication of the infection. The findings highlight the importance of Staphylococcus aureus followed by Pseudomonas aeruginosa, as the most common causative bacterial agents of CSOM. Mixed infections were prominent, Staph. aureus and P. aeruginosa combination was the most frequent.
The antibiotic susceptibility testing revealed high incidence rate of antibiotic resistance among the isolated bacteria, including MRSA which is a cause of concern. Also, decreased susceptibility of Staph. aureus to vancomycin was revealed by the current study, needing confirmation by the molecular diagnostic methods. Pseudomonas aeruginosa also showed multidrug resistance. Important role of bacterial biofilms in CSOM was detected in this study by congo red agar method and tissue culture plate method. Biofilms cause persistence, recurrence and difficult eradication of CSOM.
Recommendations:
1- Children with AOM should be properly managed and treated by suitable antibiotics, which may help in decreasing the rate of CSOM among children and teenagers.
2- Routine culture and antibiotic sensitivity tests for CSOM cases are recommended for selection of proper antibiotic therapy and prevention of emerging resistance.
3- Medical management of CSOM by use of beta-lactam antibiotics as an empirical therapy is not recommended because of the high rate of MRSA when S. aureus infection is suspected.
4- More concern about VRSA is recommended, by further studying of the resistant genes by molecular diagnostic techniques and management.
5- The use of tissue culture plate method for detection of biofilms is recommended because it shows more sensitivity and specificity than congo red agar method.
6- Use of antibiofilm measures is recommended in treatment of CSOM patients, in whom biofilms were detected by tissue culture plate method.
Summary
Chronic suppurative otitis media (CSOM) is one of the most frequently observed diseases in Otorhinolaryngology practice. It is chronic inflammation of middle ear and mastoid cavity that may present with recurrent ear discharges or otorrhoea through a tympanic perforation lasting at least two weeks. It is a public health problem in the developing part of the world.
Understanding of the microbiology of chronic otitis media is important for effective treatment, and prevention of complications and antibiotic resistance.
Over the past decades, there has been increased focus on the role of biofilm in chronic and recurrent otorhinolaryngological infections. The hallmark of biofilm is an aggregate of bacteria in a matrix, which poses high tolerance towards antibiotics and the host defense. Formation of biofilm has been implicated to sustain the infection and reduce the efficacy of antibiotic treatment.
In the present study, data were collected from December 2019 to December 2021 for 24 months in the clinics of Otorhinolaryngology department of Sohag university hospitals. One hundred and twenty ear samples were collected for detection of the causative organisms of CSOM and its ability to produce biofilms.
Out of the total number of samples, 111 (92.5%) samples had positive culture. Thirty seven (30.83%) samples had polymicrobial growth pattern, while seventy four (61.67%) samples had monomicrobial growth pattern. Nine (7.5%) samples showed no growth on the culture media.
One hundred and fourty eight bacteria were isolated, the most common isolated organism was Staphylococcus aureus, followed by Pseudomonas aeruginosa, and Staphylococcus epidermidis. A high rate of resistance to different antibiotics was noticed.
Biofilm formation was detected by congo red agar method in 67 (45.27%) organisms and by tissue culture plate method in 99 (66.9%) organisms.