Wednesday, May 30, 2012

Demonstration of Bacterial Biofilms in Chronic Otitis Media


Objective: To establish the presence of biofilms in surgical tissue specimens from patients with chronic otitis media.

Material and Methods: 22 patients with chronic otitis media scheduled for tympanomastoid surgery were enrolled in this study between September 2007 and January 2008. Biopsies of the middle ear mucosa and cultures were taken at the time of surgery. Tissues were cultured using conventional methods for Haemophilus influenzae, Pseudomonas
aeruginosa, Streptococcus pneumoniae and Staphylococcus aureus. Bacteria identification was performed using the Becton Dickinson automatic identification system. Slime forming ability was tested on congo red agar for culture positive bacteria. The presence of icaA and icaD DNA
were detected by polymerase chain reaction using forward and reverse primers for icaA and icaD for staphylococcus aureus.

Results: 6 of 22 patients’ tissue specimens were culture-positive(72.7%). 5 Staphylococcus aureus and 11 Pseudomonas aeruginosa were identified on 16 specimens. Bacterial biofilms were present on 9 of 16(56.2%) culture-positive specimens. 2 of 5(40%) Staphylococcus aureus and 7 of 11(63.6%) Pseudomonas aeruginosa produced bacterial biofilms.

Conclusion: Pseudomonas aeruginosa was the most commonly bacteria in chronic otitis media. Biofilm forming ability was higher in Pseudomonas aeruginosa compared with other bacteries. The presence of biofilms on the mucosa of patients with chronic otitis media offers a possible cause of antimicrobial therapy failure.

source:  Mediterr J Otol 2008; 4: 64-68

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