Phenotypic and Molecular Detection of Efflux Pumps in Klebsiella Pneumoniae Isolated from Sinus Infections

Abstract

Klebsiella pneumoniae is an opportunistic Gram-negative pathogen associated with severe hospital- and community-acquired infections. Its clinical significance has increased because of its growing multidrug resistance (MDR) and virulence potential. This study aimed to phenotypically and molecularly detect efflux pumps in K. pneumoniae isolated from patients with sinus infections and to identify the presence of the mdtK, acrAB, and oqxA genes. A total of 203 clinical swab samples were collected between August 2025 and February 2026 from patients attending the outpatient ENT clinic at Baquba Teaching Hospital, Diyala Governorate, Iraq. Among these, 110 samples were culture-positive, yielding 25 K. pneumoniae isolates that were identified by conventional methods and confirmed using the Vitek 2 system. Antibiotic susceptibility testing was performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines. The highest susceptibility rates were observed for imipenem (76%), chloramphenicol (76%), and doxycycline (76%), whereas lower susceptibility rates were recorded for amikacin (56%) and cefepime (56%). Twelve isolates (48%) were classified as MDR. PCR analysis showed that the acrAB and oqxA genes were detected in 100% of the MDR isolates, whereas the mdtK gene was detected in 91.6%. The high prevalence of these efflux pump genes suggests that they contribute substantially to the multidrug-resistant phenotype by promoting active antibiotic efflux. These findings highlight the importance of molecular detection of efflux pump- mediated resistance for improving antimicrobial surveillance, guiding appropriate therapy, and supporting effective infection control strategies.