Efflux Pump Activity as a Determinant of Multidrug Resistance in Acute Otitis Media-Associated Gram-Negative Pathogens

Abstract

Background: Antibiotic resistance presents a significant health concern, complicating the treatment of common infections. Acute Otitis Media (AOM) is increasingly difficult to manage due to the rise of multidrug-resistant (MDR) pathogens. This study aimed to identify the bacterial etiologies of AOM and characterize their resistance patterns, with a particular focus on the role of efflux pumps in MDR.
Methods: Samples were retrieved from AOM patients admitted to intensive care unit (ICU) and surgical wards of Al-Haboubi Hospital, Nasiriyah, Iraq. Gram staining and colony morphology were exploited for characterization of bacterial isolates. Kirby-Bauer disc diffusion method was used to assess resistance against common antibiotic agents, while Ethidium Bromide cartwheel assay was utilized for efflux pump activity and associated phenotypes.
Results: A total of 150 (100 from AOM patients and 50 healthy controls) samples were analyzed, which identified the following pathogens: Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, and Escherichia coli. The hospital-acquired pathogens showed substantially higher MDR levels compared to community-acquired strains. Likewise, the efflux pump activity was amplified in hospital-associated pathogens. Statistical analysis revealed a strong association between efflux pump activity and antibiotic susceptibility, particularly in Klebsiella pneumoniae and Pseudomonas aeruginosa isolates.
Conclusion: This study found high MDR levels in pathogens isolated from AOM patients, likely governed by active efflux mechanisms. Targeting the efflux pump activity may be a potential solution for overcoming MDR.