Title:Overexpression of Efflux Pumps AcrAB and OqxAB Contributes to
Ciprofloxacin Resistance in Clinical Isolates of K. pneumoniae
Volume: 23
Issue: 5
Author(s): Osman Albarri*, Manaf AlMatar*, Melda Meral Öcal and Fatih Köksal
Affiliation:
- Department of Biotechnology, Institute of Natural and Applied Sciences (Fen Bilimleri Enstitüsü) Çukurova University,
Adana, Turkey
- Faculty of Education and Arts, Sohar University, Sohar, 311, Sultanate of Oman
Keywords:
Klebsiella pneumoniae, efflux pumps, ciprofloxacin, CCCP, RT-PCR, transcriptional regulators.
Abstract:
Background: Infection caused by multidrug-resistant K. pneumoniae is regarded as a severe
public health concern worldwide, with most countries reporting an increase in fatality rates over
time. Efflux pumps are significant determinants of acquired and/or intrinsic resistance in K. pneumoniae.
Objectives: Our aim is to explore efflux-mediated resistance mechanisms in K. pneumoniae by using
quantitative real-time PCR in order to evaluate the expression of efflux pump genes (acrA, acrB,
oqxA, and oqxB) and pump regulators (marA, soxS, and rarA).
Methods: Efflux pump inhibitor CCCP reduced MIC values of ciprofloxacin by 2 to 64-fold in 43/46
(93%) of MDR-K. pneumoniae isolates.
Results: Compared to the control strain (untreated one), our results demonstrated that acrA, acrB,
oqxA, oqxB, marA, soxS, and rarA were overexpressed in 29 (63%), 24 (52%), 29 (63%), 24 (52%),
17 (37%), 16 (35%), and 16 (35%) of K. pneumoniae isolates, respectively. Additionally, a positive
correlation was established between the expressions of acrAB and marA (r = 0.50, r = 0.45, respectively)
and oqxAB and rarA (r = 0.462912, r = 0.519354, respectively).
Conclusion: Ciprofloxacin resistance was caused by overexpression of the efflux pump genes acrAB
and oqxAB, as well as the transcriptional regulators marA, soxS, and rarA in clinical isolates of K.
pneumonia.
