Molecular characterization of plasmid-mediated quinolone resistance genes in clinical isolates of Pseudomonas aeruginosa from Al-Muthanna Province, Iraq
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Abstract
Background and Objectives: Fluoroquinolones represent a class of antibiotics commonly used to manage Pseudomonas aeruginosa infections. The appearance of fluoroquinolone resistance in P. aeruginosa represents a critical challenge to healthcare systems.
Materials and Methods: Between January and December 2024, 650 clinical specimens were collected from Al-Hussein Teaching Hospital and Al-Rumaitha Hospital in Al-Muthanna, Iraq. P. aeruginosa was identified by conventional biochemical assays and confirmed with the Vitek 2® system. Susceptibility testing was performed by disk diffusion. PCR was conducted to detect plasmid-mediated quinolone resistance determinants, namely qnrA, qnrB, qnrD, qnrS, aac(6′)-Ib-cr, and qepA.
Results: Among the 650 specimens analyzed, 374 (57.54%) were positive for bacterial culture, with P. aeruginosa representing 40.10% (150/374) of the identified isolates. Among these, 39 (26%) exhibited resistance to at least one fluoroquinolone used. The most frequently detected gene was qnrB (67.65%), followed by qnrD (61.76%), qnrS (55.88%), aac(6')-Ib-cr (47.00%), and qepA (41.17%), while qnrA and qnrC were not detected in any isolate.
Conclusion: The fluoroquinolone resistance and widespread occurrence in isolates of P. aeruginosa from Al-Muthanna Province pose a challenge to infection management, as mobile genetic elements facilitate the rapid dissemination of resistance and limit available therapeutic options, emphasizing the necessity for genetic monitoring and effective antibiotic management.
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26. Ismail SJ, Mahmoud SS. First detection of New Delhi metallo-β-lactamases variants (NDM-1, NDM-2) among Pseudomonas aeruginosa isolated from Iraqi hospitals. Iran J Microbiol 2018; 10: 98-103.
27. Jabalameli F, Mirsalehian A, Sotoudeh N, Jabalameli L, Aligholi M, Khoramian B, et al. Multiple-locus variable number of tandem repeats (VNTR) fingerprinting (MLVF) and antibacterial resistance profiles of ESBL-producing Pseudomonas aeruginosa among burnt patients in Tehran. Burns 2011; 37: 1202-1207.
28. Er H, Altındiş M, Aşık G, Demir C. Molecular epidemiology of beta-lactamases in ceftazidime-resistant Pseudomonas aeruginosa isolates. Mikrobiyol Bul 2015; 49: 156-165.
29. Nouri R, Ahangarzadeh Rezaee M, Hasani A, Aghazadeh M, Asgharzadeh M. The role of gyrA and parC mutations in fluoroquinolones-resistant Pseudomonas aeruginosa isolates from Iran. Braz J Microbiol 2016; 47: 925-930.
30. El-Badawy MF, Alrobaian MM, Shohayeb MM, Abdelwahab SF. Investigation of six plasmid-mediated quinolone resistance genes among clinical isolates of Pseudomonas: a genotypic study in Saudi Arabia. Infect Drug Resist 2019; 12: 915-923.
31. Heward E, Cullen M, Hobson J. Microbiology and antimicrobial susceptibility of otitis externa: a changing pattern of antimicrobial resistance. J Laryngol Otol 2018; 132: 314-317.
32. Noonan KY, Kim SY, Wong LY, Martin IW, Schwartzman JD, Saunders JE. Treatment of ciprofloxacin-resistant ear infections. Otol Neurotol 2018; 39(9): e837-e842.
33. Saki M, Farajzadeh Sheikh A, Seyed-Mohammadi S, Asareh Zadegan Dezfuli A, Shahin M, Tabasi M, et al. Occurrence of plasmid-mediated quinolone resistance genes in Pseudomonas aeruginosa strains isolated from clinical specimens in southwest Iran: a multicentral study. Sci Rep 2022; 12: 2296.
2. Reynolds D, Kollef M. The epidemiology, pathogenesis, and treatment of Pseudomonas aeruginosa infections: an update. Drugs 2021; 81: 2117-2131.
3. Kunz Coyne AJ, El Ghali A, Holger D, Rebold N, Rybak MJ. Therapeutic strategies for emerging multidrug-resistant Pseudomonas aeruginosa. Infect Dis Ther 2022; 11: 661-682.
4. Chan T, Bunce PE. Fluoroquinolone antimicrobial drugs. CMAJ 2017; 189(17): E638.
5. Hooper DC, Jacoby GA. Mechanisms of drug resistance: quinolone resistance. Ann N Y Acad Sci 2015; 1354: 12-31.
6. Fernández L, Hancock REW. Adaptive and mutational resistance: role of porins and efflux pumps in drug resistance. Clin Microbiol Rev 2012; 25: 661-681.
7. Strahilevitz J, Jacoby GA, Hooper DC, Robicsek A. Plasmid-mediated quinolone resistance: a multifaceted threat. Clin Microbiol Rev 2009; 22: 664-689.
8. Venkataramana GP, Lalitha AKV, Mariappan S, Sekar U. Plasmid-mediated fluoroquinolone resistance in Pseudomonas aeruginosa and Acinetobacter baumannii. J Lab Physicians 2022; 14: 271-277.
9. Robicsek A, Jacoby GA, Hooper DC. The worldwide emergence of plasmid-mediated quinolone resistance. Lancet Infect Dis 2006; 6: 629-640.
10. Ruiz E, Sáenz Y, Zarazaga M, Rocha-Gracia R, Martínez-Martínez L, Arlet G, et al. qnr, aac(6′)-Ib-cr and qepA genes in Escherichia coli and Klebsiella spp.: genetic environments and plasmid and chromosomal location. J Antimicrob Chemother 2012; 67: 886-897.
11. Yang C, Wang X, Zhao X, Wu Y, Lin J, Zhao Y, et al. Effect of fluorine atoms and piperazine rings on biotoxicity of norfloxacin analogues: combined experimental and theoretical study. Environ Health (Wash) 2024; 2: 886-901.
12. MacFaddin JF (2000). Biochemical tests for identification of medical bacteria, 3rd ed. Lippincott Williams and Wilkins, Philadelphia.
13. Callebaut K, Stoefs A, Emmerechts K, Vandoorslaer K, Wybo I, De Geyter D, et al. Evaluation of automated disk diffusion antimicrobial susceptibility testing using Radian® in-line carousel. Curr Microbiol 2024; 81: 196.
14. Clinical and Laboratory Standards Institute. Performance standards for antimicrobial susceptibility testing. 35th ed. CLSI supplement M100. Wayne (PA): CLSI; 2025.
15. Le TA, Fabre L, Roumagnac P, Grimont PA, Scavizzi MR, Weill FX. Clonal expansion and microevolution of quinolone-resistant Salmonella enterica serotype Typhi in Vietnam from 1996 to 2004. J Clin Microbiol 2007; 45: 3485-3492.
16. Li P, Liu D, Zhang X, Tuo H, Lei C, Xie X, et al. Characterization of plasmid-mediated quinolone resistance in gram-negative bacterial strains from animals and humans in China. Microb Drug Resist 2019; 25: 1050-1056.
17. Robicsek A, Strahilevitz J, Sahm DF, Jacoby GA, Hooper DC. Qnr prevalence in ceftazidime-resistant Enterobacteriaceae isolates from the United States. Antimicrob Agents Chemother 2006; 50: 2872-2874.
18. Park CH, Robicsek A, Jacoby GA, Sahm D, Hooper DC. Prevalence in the United States of aac(6')-Ib-cr encoding a ciprofloxacin-modifying enzyme. Antimicrob Agents Chemother 2006; 50: 3953-3955.
19. Yamane K, Wachino J, Suzuki S, Arakawa Y. Plasmid-mediated qepA gene among Escherichia coli clinical isolates from Japan. Antimicrob Agents Chemother 2008; 52: 1564-1566.
20. Ali SM, Soor TAH, Ahmed GA, Mhdin GA, Othman GA, Faiq SM. Distribution and molecular characterization of antibiotic-resistant Pseudomonas aeruginosa in hospital settings of Sulaymaniyah, Iraq. Pol J Microbiol 2024; 73: 467-473.
21. Alkhulaifi ZM, Mohammed KA. Prevalence and molecular analysis of antibiotic resistance of Pseudomonas aeruginosa isolated from clinical and environmental specimens in Basra, Iraq. Iran J Microbiol 2023; 15: 45-54.
22. Pachori P, Gothalwal R, Gandhi P. Emergence of antibiotic resistant Pseudomonas aeruginosa in intensive care unit: a critical review. Genes Dis 2019; 6: 109-119.
23. Qin S, Xiao W, Zhou C, Pu Q, Deng X, Lan L, et al. Pseudomonas aeruginosa: Pathogenesis, virulence factors, antibiotic resistance, interaction with host, technology advances, and emerging therapeutics. Signal Transduct Target Ther 2022; 7: 199.
24. Rashid Mahmood A, Mansour Hussein N. Study of Antibiotic Resistant Genes in Pseudomonas aeruginosa Isolated from Burns and Wounds. Arch Razi Inst 2022; 77: 403-411.
25. Harsh T, Patil HV, Patil SR. Prevalence and antimicrobial susceptibility pattern of Pseudomonas aeruginosa isolates from various clinical specimens in a tertiary care hospital: an analysis of resistance trends and implications for treatment strategies. Cureus 2024; 16(10): e72556.
26. Ismail SJ, Mahmoud SS. First detection of New Delhi metallo-β-lactamases variants (NDM-1, NDM-2) among Pseudomonas aeruginosa isolated from Iraqi hospitals. Iran J Microbiol 2018; 10: 98-103.
27. Jabalameli F, Mirsalehian A, Sotoudeh N, Jabalameli L, Aligholi M, Khoramian B, et al. Multiple-locus variable number of tandem repeats (VNTR) fingerprinting (MLVF) and antibacterial resistance profiles of ESBL-producing Pseudomonas aeruginosa among burnt patients in Tehran. Burns 2011; 37: 1202-1207.
28. Er H, Altındiş M, Aşık G, Demir C. Molecular epidemiology of beta-lactamases in ceftazidime-resistant Pseudomonas aeruginosa isolates. Mikrobiyol Bul 2015; 49: 156-165.
29. Nouri R, Ahangarzadeh Rezaee M, Hasani A, Aghazadeh M, Asgharzadeh M. The role of gyrA and parC mutations in fluoroquinolones-resistant Pseudomonas aeruginosa isolates from Iran. Braz J Microbiol 2016; 47: 925-930.
30. El-Badawy MF, Alrobaian MM, Shohayeb MM, Abdelwahab SF. Investigation of six plasmid-mediated quinolone resistance genes among clinical isolates of Pseudomonas: a genotypic study in Saudi Arabia. Infect Drug Resist 2019; 12: 915-923.
31. Heward E, Cullen M, Hobson J. Microbiology and antimicrobial susceptibility of otitis externa: a changing pattern of antimicrobial resistance. J Laryngol Otol 2018; 132: 314-317.
32. Noonan KY, Kim SY, Wong LY, Martin IW, Schwartzman JD, Saunders JE. Treatment of ciprofloxacin-resistant ear infections. Otol Neurotol 2018; 39(9): e837-e842.
33. Saki M, Farajzadeh Sheikh A, Seyed-Mohammadi S, Asareh Zadegan Dezfuli A, Shahin M, Tabasi M, et al. Occurrence of plasmid-mediated quinolone resistance genes in Pseudomonas aeruginosa strains isolated from clinical specimens in southwest Iran: a multicentral study. Sci Rep 2022; 12: 2296.
| Files | ||
| Issue | Vol 18 No 2 (2026) | |
| Section | Original Article(s) | |
| Keywords | ||
| Pseudomonas aeruginosa Drug resistance Fluoroquinolones Ciprofloxacin Levofloxacin Polymerase chain reaction Ofloxacin | ||
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How to Cite
1.
Al-Khafaji S, Al-Mayahi F. Molecular characterization of plasmid-mediated quinolone resistance genes in clinical isolates of Pseudomonas aeruginosa from Al-Muthanna Province, Iraq. Iran J Microbiol. 2026;18(2):235-243.
