Prevalence of oqxAB Efflux Pump Genes and their Association with Antibiotic Resistance and Biofilm Formation in Klebsiella pneumoniae Clinical Isolates
DOI:
https://doi.org/10.47419/bjbabs.v7i3.457Keywords:
Klebsiella pneumoniae, oqxAB Efflux pump genes, Biofilm, antibiotic resistanceAbstract
Background: Klebsiella pneumoniae is an opportunistic bacterium that frequently causes healthcare-associated infections. Virulence factors that contribute to its persistence include efflux pump activity, antibiotic resistance, and the formation of biofilms.
Objective: This research seeks to identify the prevalence of oqxAB efflux pump genes in K. pneumoniae patient-derived strains and their relation to the development of biofilms and resistance to antibiotics.
Methods: Clinical samples (blood, urine, sputum, and burn wounds) were obtained from inpatients and outpatients in Baghdad hospitals between October 2024 and March 2025 for isolation of K. pneumoniae. Identification was performed by morphological, cultural, and biochemical assays, followed by confirmation through the VITEK 2 system. Susceptibility to antibiotics, biofilm formation, and the presence of oqxA and oqxB genes were evaluated using the Kirby–Bauer technique, microtiter plate assay, and conventional PCR, respectively.
Results: In total, 165 clinical specimens were obtained from different sources. After culturing, 117 bacterial isolates exhibiting characteristic growth patterns appeared; among them, 30 bacterial isolates were classified as K. pneumoniae. PCR results showed a high prevalence of efflux pump genes oqxA (93.3%) and oqxB (100%) in K. pneumoniae isolates. The presence of these genes demonstrated a significant connection to antibiotic resistance and the ability to form biofilms.
Conclusion: According to this study, OqxAB genes could potentially be spread by hospital-acquired K. pneumoniae. Increased antibiotic resistance and varied biofilm-forming capacity were associated with the occurrence of the oqxA and oqxB efflux pump genes.
Downloads
References
[1] Dai, P.; Hu, D. The making of hypervirulent Klebsiella pneumoniae. J. Clin. Lab. Anal. 2022; 36(12): e24743. https://doi.org/10.1002/jcla.24743
[2] Jondle, C.N.; Gupta, K.; Mishra, B.B.; Sharma, J. Klebsiella pneumoniae infection of murine neutrophils impairs their efferocytic clearance by modulating cell death machinery. PLoS Pathog. 2018; 14(10): e1007338. https://doi.org/10.1371/journal.ppat.1007338
[3] Guerra, M.E.S.; Destro, G.; Vieira, B.; Lima, A.S.; Ferraz, L.F.C., et al. Klebsiella pneumoniae biofilms and their role in disease pathogenesis. Front. Cell Infect. Microbiol. 2022; 12: 877995. https://doi.org/10.3389/fcimb.2022.877995
[4] Alharbi, M.T.; Almuhayawi, M.S.; Nagshabandi, M.K.; Tarabulsi, M.K.; Alruhaili, M.H., et al. Antimicrobial resistance pattern, pathogenicity and molecular properties of hypervirulent Klebsiella pneumoniae (hvKp) among hospital-acquired infections in the intensive care unit (ICU). Microorganisms. 2023; 11(3): 661. https://doi.org/10.3390/microorganisms11030661
[5] Zaborskytė, G. Evolutionary trajectories of Klebsiella pneumoniae: from experimental biofilm evolution to a hospital outbreak. Doctoral dissertation, Acta Universitatis Upsaliensis, Uppsala, Sweden, 2022. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-470671
[6] Karami-Zarandi, M.; Rahdar, H.A.; Esmaeili, H.; Ranjbar, R. Klebsiella pneumoniae: an update on antibiotic resistance mechanisms. Future Microbiol. 2023; 18(1): 65–81. https://doi.org/10.2217/fmb-2022-0168
[7] Amereh, F.; Arabestani, M.R.; Shokoohizadeh, L. Relationship of OqxAB efflux pump to antibiotic resistance, mainly fluoroquinolones in Klebsiella pneumoniae isolated from hospitalized patients. Iran J. Basic Med. Sci. 2023; 26(1): 93–100. https://doi.org/10.22038/IJBMS.2022.68568.15174
[8] Singh, R.P.; Kapoor, A.; Sinha, A.; Ma, Y.; Shankar, M. Virulence factors of Klebsiella pneumoniae: insights into canonical and emerging mechanisms driving pathogenicity and drug resistance. The Microbe. 2025; 7: 100289. https://doi.org/10.1016/j.microb.2025.100289
[9] Radi, N.A.; Abd Elkader, E.A.; Mohamad, O.M.; Wahba, A.M.G.E. A study on the antimicrobial resistance of Klebsiella pneumoniae isolated from patients with urinary tract infections and its correlation with tendency of biofilm formation. Egypt J. Med. Res. 2023; 4(3): 119–128.
[10] De La Fuente-Núñez, C.; Cardoso, M.H.; de Souza Cândido, E.; Franco, O.L.; Hancock, R.E.; Synthetic antibiofilm peptides. Biochim. Biophys. Acta. Biomembr. 1858(5): 1061–1069. 2016. https://doi.org/10.1016/j.bbamem.2015.12.015
[11] Li, Y.; Ni, M. Regulation of biofilm formation in Klebsiella pneumoniae. Front Microbiol. 2023; 14: 1238482. https://doi.org/10.3389/fmicb.2023.1238482
[12] Al-Bayati, M.; Samarasinghe, S. Biofilm and gene expression characteristics of the carbapenem-resistant enterobacterales, Escherichia coli IMP, and Klebsiella pneumoniae NDM-1 associated with common bacterial infections. Int. J. Environ. Res. Public Health. 2022; 19(8): 4788. https://doi.org/10.3390/ijerph19084788
[13] Ni, R.T.; Onishi, M.; Mizusawa, M.; Kitagawa, R.; Kishino, T., et al. The role of RND-type efflux pumps in multidrug-resistant mutants of Klebsiella pneumoniae. Sci. Rep. 2020; 10(1): 10876, https://doi.org/10.1038/s41598-020-67889-y
[14] Razavi, S.; Mirnejad, R.; Babapour, E. Involvement of AcrAB and OqxAB efflux pumps in antimicrobial resistance of clinical isolates of Klebsiella pneumoniae. 2020; J. Appl. Biotechnol. Rep. 7(4): 251–257.
[15] Li, J.; Zhang, H.; Ning, J.; Sajid, A.; Cheng, G.; Yuan, Z., et al. The nature and epidemiology of OqxAB, a multidrug efflux pump. Antimicrob. Resist. Infect. Control. 2019; 8(1): 44. https://doi.org/10.1186/s13756-019-0489-3
[16] Al-Ruobayiee, M.R.; Ibrahim, A.H. The relationship between OqxAB efflux pump and drug resistance in Klebsiella pneumoniae isolated from clinical sources Al-Rafidain J. Med. Sci. 2023; 5(1S): S106–S112.
[17] Bharatham, N.; Bhowmik, P.; Aoki, M.; Okada, U.; Sharma, S., et al. Structure and function relationship of OqxB efflux pump from Klebsiella pneumoniae. Nat. Commun. 2021; 12(1): 5400 https://doi.org/10.1038/s41467-021-25422-2
[18] Mahrous, S.H.; El-Balkemy, F.A.; Abo-Zeid, N.Z.; El-Mekkawy, M.F.; El Damaty, H.M., et al. Antibacterial and anti-biofilm activities of cinnamon oil against multidrug-resistant Klebsiella pneumoniae isolated from pneumonic sheep and goats. Pathogens. 2023; 12(9): 1138. https://doi.org/10.3390/pathogens12091138
[19] Jan, H. Kirby–Bauer disk diffusion susceptibility test protocol. American Society for Microbiology, 2009. Available from: https://asm.org/getattachment/2594ce26-bd44-47f6-8287-0657aa9185ad/Kirby-Bauer-Disk-Diffusion-Susceptibility-Test-Protocol
[20] Clinical and Laboratory Standards Institute (CLSI); Performance standards for antimicrobial susceptibility testing. CLSI supplement M100. 34th ed.; CLSI: Wayne, PA, USA, 2024. p. 58–68.
[21] Nagant, C.; Pitts, B.; Stewart, P.S.; Feng, Y.; Savage, P.B.; Dehaye, J.P. Study of the effect of antimicrobial peptide mimic, CSA-13, on an established biofilm formed by Pseudomonas aeruginosa. Microbiol. Open. 2013; 2(2): 318–325. https://doi.org/10.1002/mbo3.70
[22] Haney, E.F.; Trimble, M.J.; Hancock, R.E.W. Microtiter plate assays to assess antibiofilm activity against bacteria. Nat. Protoc. 2021; 16(5): 2615–2632. https://doi.org/10.1038/s41596-021-00517-0
[23] Ghazi, N.M.; Jasim, H.M. Effect of bovine serum on quorum sensing genes expression in MDR resistant Pseudomonas aeruginosa. Membr Technol, 2025.
[24] Worku, M.; Belay, S.; Molla, T.; Aynalem, M.; Assefa, M. Prevalence and antimicrobial susceptibility pattern of Klebsiella pneumoniae isolated from various clinical samples at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia. BMC Infect. Dis. 2024; 24(1): 917. https://doi.org/10.1186/s12879-024-10120-5
[25] Abdullah, I.T.; Hasib, F.A.; Mohammad, F.I. Studying the prevalence of multidrug resistant Klebsiella pneumoniae in Kirkuk city. 2023; NTU J. Agric. Vet. Sci. 3(4):171–177.
[26] Sadeq, Z.E.; Lafta, I.J. Tigecycline is the most effective against multidrug-resistant Klebsiella pneumoniae recovered from burn wound infections in two hospitals in Al-Kut city, Iraq. Iraq J. Sci. 2024; 659–674.
[27] Ali, M.R.; Ibrahim, A.H. Correlation between efflux pump genes and biofilm formation with antibiotic resistance of Klebsiella pneumoniae. 2025; Iraq J. Sci. 114–127.
[28] Usman, N.I.; Abdulwahab, N.M.; Sulaiman, M.J. Multidrug resistance (MDR), extensive drug resistance (XDR) and pan drug resistance (PDR) Klebsiella pneumoniae from clinical samples. SLU J. Sci. Technol. 2022; 3: 42–50.
[29] Hassan, A.; Usman, J.; Kaleem, F.; Omair, M.; Khalid, A.; Iqbal, M. Evaluation of different detection methods of biofilm formation in the clinical isolates. Braz. J. Infect. Dis. 2011; 15(4): 305–311. https://doi.org/10.1016/S1413-8670(11)70197-0
[30] Cherif-Antar, A.; Moussa-Boudjemâa, B.; Didouh, N.; Medjahdi, K.; Mayo, B.; Flórez, A.B. Diversity and biofilm-forming capability of bacteria recovered from stainless steel pipes of a milk-processing dairy plant. Dairy Sci. Technol. 2016; 96: 27–38. https://doi.org/10.1007/s13594-015-0252-3
[31] Tuon, F.F.; Suss, P.H.; Telles, J.P.; Dantas, L.R.; Borges, N.H., et al. Antimicrobial treatment of Staphylococcus aureus biofilms. Antibiotics (Basel). 2023; 12(1): 87. https://doi.org/10.3390/antibiotics12010087
[32] Agarwal, A.; Jain, A. Association between drug resistance and production of biofilm in staphylococci. Indian J. Med. Res. 2012; 135(4): 562–564. https://doi.org/10.4103/0971-5916.96315
[33] Munita, J.M.; Arias, C.A. Mechanisms of antibiotic resistance. In Virulence mechanisms of bacterial pathogens, 5th ed.; Kudva, I.T.; Cornick, N.A.; Plummer, P.J.; Zhang, Q.; Nicholson, T.L., et al., Eds.; ASM Press: Washington, DC, USA, pp. 481–511, 2016. https://doi.org/10.1128/9781555819286.ch20
[34] Wyres, K.L.; Holt, K.E. Klebsiella pneumoniae as a key trafficker of drug resistance genes from environmental to clinically important bacteria. Curr. Opin. Microbiol. 2018; 45: 131–139. https://doi.org/10.1016/j.mib.2018.04.004
[35] Alghamdi, A.; Hafiz, T.; Almaghrabi, R.; Al-Qahtani, A.; Hammad, E.; Obeid, D., et al. Multidrug resistance efflux pump expression in uropathogenic Gram-negative bacteria in organ transplant recipients. J. Infect. Dev. Ctries. 19(5): 2025; 641–648. https://doi.org/10.3855/jidc.19052
[36] Tang, M.; Wei, X.; Wan, X.; Ding, Z.; Ding, Y.; Liu, J. The role and relationship with efflux pump of biofilm formation in Klebsiella pneumoniae. Microb. Pathog. 2020; 147: 104244. https://doi.org/10.1016/j.micpath.2020.104244
[37] Akinpelu, S.; Ajayi, A.; Smith, S.I.; Adeleye, A.I. Efflux pump activity, biofilm formation and antibiotic resistance profile of Klebsiella spp. isolated from clinical samples at Lagos University Teaching Hospital. BMC Res. Notes. 2020; 13(1): 258. https://doi.org/10.1186/s13104-020-05087-3
[38] Mirzaie, A.; Ranjbar, R. Antibiotic resistance, virulence-associated genes analysis and molecular typing of Klebsiella pneumoniae strains recovered from clinical samples. AMB Express. 2021; 11(1): 122. https://doi.org/10.1186/s13568-021-01273-1
Additional Files
Published
Issue
Section
Categories
License
Copyright (c) 2026 Dalal Farhad Alrawanduzy, Hameed M. Jasim
This work is licensed under a Creative Commons Attribution 4.0 International License.
The authors retain all proprietary rights, including copyright, such as patent and trademark rights and rights to any process or procedure described in the article.
