Document Type : Original Research


1 Department of Microbiology, Faculty of Medicine, Shahed University, Tehran, Iran

2 Baqiyatallah University of Medical Sciences, Tehran, Iran


Background & Objective: Acinetobacter baumannii strains harboring Meallobetalactamases (MBL) pose a significant threat in the context of nosocomial infections. The present investigation was undertaken with the objective of devising a Multiplex PCR methodology for the concurrent detection of MBL genes within A. baumannii strains prevalent in Tehran City, Iran.
Methods: Between October 2020 and February 2021, 100 strains of A. baumannii were procured from burn specimens of hospitalized patients at Motahhari Hospital in Tehran. The identification of A. baumannii strains involved conventional biochemical techniques, coupled with confirmation of the presence of the bla OXA-51 gene. Antibiotic susceptibility was assessed using the Kirby–Bauer disc diffusion test. MBL-producing strains were characterized through a phenotypic approach employing the combined disk test, alongside Multiplex PCR for the simultaneous identification of bla VIM, bla IMP, bla GIM, and bla NDM genes. Statistical analyses were conducted using the chi-square test, with SPSS version 20.0 employed for data processing.
Results: Among 100 strains examined, 96.1% exhibited positivity for MBL, as determined by the combined disk test. The study revealed a predominance of extensively drug-resistant (XDR) strains, with colistin demonstrating the highest level of sensitivity. The genotypic assay unveiled that Multiplex PCR identified bla VIM, bla NDM, and bla IMP in 20 strains, bla VIM and bla NDM in 30 strains, and exclusively the bla NDM gene in 45 strains. Notably, the Multiplex PCR technique exhibited the capacity to concurrently detect MBL genes (bla VIM, bla IMP, bla GIM, bla NDM) in 2 strains.
Conclusion: The current investigation underscores prevalence of the bla NDM gene within clinical strains of A. baumannii. Furthermore, Multiplex PCR emerges as a robust and highly sensitive technique for rapid discernment of the MBL genes within in A. baumannii strains.


Main Subjects

  1. Howard A, O'Donoghue M, Feeney A, Sleator RD. Acinetobacter baumannii: an emerging opportunistic pathogen. Virulence. 2012;3(3): 243-50. [DOI:10.4161/viru.19700] [PMID]
  2. Fournier PE, Richet H, Weinstein RA. The epidemiology and control of Acinetobacter baumannii in health care facilities. Clin Infect Dis. 2006;42(5):692-9. [DOI:10.1086/500202] [PMID]
  3. Montefour K, Frieden J, Hurst S, Helmich C, Headley D, Martin M, et al. Acinetobacter baumannii: an emerging multidrug-resistant pathogen in critical care. Crit Care Nurs. 2008; 28(1):15-25. [DOI:10.4037/ccn2008.28.1.15] [PMID]
  4. Manchanda V, Sanchaita S, Singh N. Multidrug resistant acinetobacter. J Global Infect Dis. 2010;2(3):291. [DOI:10.4103/0974-777X.68538] [PMID]
  5. Tsakris A, Ikonomidis A, Poulou A, Spanakis N, Vrizas D, Diomidous M, et al. Clusters of imipenem-resistant Acinetobacter baumannii clones producing different carbapenemases in an intensive care unit. Clin Microbiol Infect. 2008;14(6):588-94. [DOI:10.1111/j.1469-0691.2008.01996.x] [PMID]
  6. Gordon NC, Wareham DW. Multidrug-resistant Acinetobacter baumannii: mechanisms of virulence and resistance. Int J Antimicrob Agents. 2010;35(3):219-26. [PMID] [DOI:10.1016/j.ijantimicag.2009.10.024]
  7. Lin M-F, Lan C-Y. Antimicrobial resistance in Acinetobacter baumannii: From bench to bedside. World J Clin Cases. 2014;2(12):787. [DOI:10.12998/wjcc.v2.i12.787] [PMID]
  8. Scaife W, YOUNG H-K, PATON RH, AMYES SG. Transferable imipenem-resistance in Acinetobacter species from a clinical source. J Antimicrob Chemother. 1995;36(3):585-6. [DOI:10.1093/jac/36.3.585] [PMID]
  9. Jeon JH, Lee JH, Lee JJ, Park KS, Karim AM, Lee C-R, et al. Structural basis for carbapenem-hydrolyzing mechanisms of carbapenemases conferring antibiotic resistance. Int J Molecul Sci. 2015;16(5):9654-92. [DOI:10.3390/ijms16059654] [PMID]
  10. Bebrone C. Metallo-β-lactamases (classification, activity, genetic organization, structure, zinc coordination) and their superfamily. Biochem Pharmacol. 2007;74(12):1686-701. [DOI:10.1016/j.bcp.2007.05.021] [PMID]
  11. Anoar KA, Ali FA, Omer SA. Detection of Metallo [Beta]-Lactamase Enzyme in Some Gram Negative Bacteria Isolated From Burn Patients on Sulaimani City, Iraq. Euro Sci J. 2014;10(3).
  12. Tsakris A, Poulou A, Kristo I, Pittaras T, Spanakis N, Pournaras S, et al. Large dissemination of VIM-2-metallo-β-lactamase-producing Pseudomonas aeruginosa strains causing health care-associated community-onset infections. J Clin Microbiol. 2009;47(11):3524-9. [DOI:10.1128/JCM.01099-09] [PMID]
  13. Wayne P. Performance Standards for Antimicrobial Susceptibility Testing. Clinical and Laboratory Standards Institute (CLSI) 28th Informational Supplement. 2017.
  14. Nowak P, Paluchowska P, Budak A. Distribution of blaOXA genes among carbapenem-resistant Acinetobacter baumannii nosocomial strains in Poland. New Microbiol. 2012;35(3):317-25.
  15. Singh H, Thangaraj P, Chakrabarti A. Acinetobacter baumannii: a brief account of mechanisms of multidrug resistance and current and future therapeutic management. Journal of clinical and diagnostic research: JCDR. 2013; 7(11):2602. [DOI:10.7860/JCDR/2013/6337.3626] [PMID]
  16. Raieszadeh M, Sabzi N, Esmaeili D. Detection of Antibiotic Resistance of Broad-Spectrum Beta-Lactams by Multiplex PCR Method. 2021. [DOI:10.21203/]
  17. Soltani B, Heidari H, Ebrahim-Saraie HS, Hadi N, Mardaneh J, Motamedifar M. Molecular characteristics of multiple and extensive drug-resistant Acinetobacter baumannii isolates obtained from hospitalized patients in Southwestern Iran. Le infezioni in medicina: rivista periodica di eziologia, epidemiologia, diagnostica, clinica e terapia delle patologie infettive. 2018;26(1):67-76.
  18. Asadian M, Azimi L, Alinejad F, Ostadi Y, Lari AR. Molecular characterization of Acinetobacter baumannii isolated from ventilator-associated pneumonia and burn wound colonization by random amplified polymorphic DNA polymerase chain reaction and the relationship between antibiotic susceptibility and biofilm production. Adv Biomed Res. 2019;8. [DOI:10.4103/abr.abr_256_18] [PMID]
  19. As SG. CLSI based antibiogram profile and the detection of MDR and XDR strains of Acinetobacter baumannii isolated from urine samples. Med J the Islamic Republic Iran. 2019;33:3.
  20. Monfared AM, Rezaei A, Poursina F, Faghri J. Detection of genes involved in biofilm formation in MDR and XDR Acinetobacter baumannii isolated from human clinical specimens in Isfahan, Iran. Arch Clin Infect Dis. 2019;14(2):6. [DOI:10.5812/archcid.85766]
  21. Saleh HH, El-Sayed AK. Traditional and Molecular Gene Detection (blaIMP-1 and blaIMP) of multi-drug resistant Acinetobacter baumannii. Catrina Int J Environ Sci. 2021;24(1): 75-80. [DOI:10.21608/cat.2022.244092]
  22. Rouf M, Nazir A, Karnain O, Akhter S. Comparison of Various Phenotypic Methods in Detection of Carbapenemases and Metallo-Beta-Lactamases (MBL) in Carbapenem Resistant Clinlical Isolates of Acinetobacter Species at A Tertiary Care Centre. J Res Appl Basic Med Sci. 2022;8(3):110-7. [DOI:10.52547/rabms.8.3.110]
  23. Ranjbar R, Zayeri S, Mirzaie A. Development of multiplex PCR for rapid detection of metallo-β-lactamase genes in clinical isolates of Acinetobacter baumannii. Iran J Microbiol. 2020;12(2):107. [DOI:10.18502/ijm.v12i2.2615] [PMID]
  24. Massik A, Hibaoui L, Arhoune B, Yahyaoui G, Oumokhtar B, Mahmoud M. Detection of metallo-beta lactamases and oxacillinase genes in carbapenem-resistant Acinetobacter baumannii strains isolated in Morocco. Pan African Med J. 2021;40(1). [PMID] [DOI:10.11604/pamj.2021.40.210.28663]
  25. Sedighi I, Arabestani MR, Rahimbakhsh A, Karimitabar Z, Alikhani MY. Dissemination of extended-spectrum β-lactamases and quinolone resistance genes among clinical isolates of uropathogenic Escherichia coli in children. Jundishapur J Microbiol. 2015;8(7). [DOI:10.5812/jjm.19184v2]
  26. Darvishi M. Virulence factors profile and antimicrobial resistance of Acinetobacter baumannii strains isolated from various infections recovered from immunosuppressive patients. Biomed Pharmacol J. 2016;9(3):1057-62 [DOI:10.13005/bpj/1048]