Pseudomonas aeruginosa in Chronic Suppurative Otitis Media.

Background: Chronic suppurative otitis media (CSOM) has caused many hearing disorder cases in developing countries. Inappropriate antibiotic use resulted in a shift of bacterial resistance. The biofilm-forming bacteria, like Pseudomonas aeruginosa, was a common germ detected in CSOM that contributed to a poor prognosis. This study aimed to investigate the bacterial pattern from samples taken from CSOM patients regarding its antibiotic susceptibility and the antibiofilm activity of acetic acid against P. aeruginosa.

Materials and methods: Sterile swabs of forty-five patients with CSOM were collected, followed by isolation of bacterial pathogens, identification, and evaluation of antibiotic sensitivity using modified Kirby Bauer disc diffusion protocol. In vitro testing was done by adding acetic acid to P. aeruginosa culture to gauge the minimum concentration of biofilm inhibition and eradication. They were conducted using the microtiter plate assay method and quantified with an ELISA reader. The data were analyzed statistically using One-Way ANOVA and Tukey Honestly Significant Difference post hoc test.

Results: The samples obtained from 31 of 45 CSOM patients showed positive microbial growth; 26 (57.78%) had a monomicrobial pattern, and 5 (11.11%) had a polymicrobial pattern. The researcher ascertained that 24 isolates, representing 66.67%, were gram-negative bacteria, with P.-aeruginosa identified as the predominant species. P. aeruginosa isolates were sensitive to several antibiotics, including meropenem, amikacin, piperacillin-tazobactam, ceftazidime, and cefoperazone-sulbactam with a rate of 93.33%. The minimum concentration of acetic acid required to qualify as the minimum biofilm inhibitory concentration (MBIC) was determined to be 0.16%, yielding an inhibition rate of 26.79%. A concentration of 0.31% was identified as the minimum biofilm eradication concentration (MBEC), achieving an eradication rate of 77.27%.

Conclusion: P. aeruginosa, the most common bacteria found in CSOM samples, was sensitive to imipenem, amikacin, piperacillin-tazobactam, ceftazidime, and cefoperazone-sulbactam. Acetic acid suppresses P. aeruginosa bacterial biofilm formation at MBIC of 0.16% and MBEC of 0.31%.