Overexpression of AdeABC Efflux Pump Genes adeR and adeS in Multidrug-Resistant Acinetobacter baumannii Isolated from Burn Patients in Baghdad

Salem, Hanan D.; Al-Draghi, Wathiq A.

doi:10.21608/ejmm.2025.379342.1594

Overexpression of AdeABC Efflux Pump Genes adeR and adeS in Multidrug-Resistant Acinetobacter baumannii Isolated from Burn Patients in Baghdad

Document Type : New and original researches in the field of Microbiology.

Authors

Department Genetic Engineering, Institute of Genetic Engineering and Biotechnology for Postgraduate Studies, University of Baghdad, Baghdad, Iraq

10.21608/ejmm.2025.379342.1594

Abstract

Background: Acinetobacter baumannii is a critical nosocomial pathogen with rising multidrug resistance (MDR) driven by mechanisms such as efflux pump overexpression: This study investigated antibiotic resistance profiles and the role of AdeABC efflux pump genes (adeR, adeS) in Acinetobacter baumannii isolates from burn patients in Baghdad, Iraq. Methodology: A total of 200 clinical samples were collected from burn units in Baghdad hospitals (December 2023–March 2024) The ages of the patients ranged from (14 to 81 years), both males and females, where the proportion of females being was higher than that of males. 60% for females and 40% for males, Isolates was identified via biochemical assays and the VITEK 2 system and MIC determinations were performed, followed by PCR and qPCR to detect expressione adeR, adeS, and 16S rRNA genes Results: Among 20 confirmed Acinetobacter baumannii isolates, 75% harbored adeR and 70% adeS. MDR strains exhibited significant adeR (2.71–2.75-fold; p ≤ 0.01) and adeS overexpression (up to 40.50-fold; p=0.0001), which correlated with resistance to carbapenems (imipenem MIC >32 µg/mL), fluoroquinolones (ciprofloxacin MIC >8 µg/mL), and aminoglycosides (gentamicin MIC >16µg/mL). Mutational analysis revealed that adeS truncations (Δ95–157) and adeR substitutions were linked to efflux pump hyperactivity. Conclusion: This study revealed overexpression of efflux pump genes adeR and adeS in Acinetobacter baumannii MDR strains, indicating the need for efflux pump inhibitors in therapeutic regimens and genomic surveillance for infection control policies.

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