Relationship between Biofilm Formation and Antibiotic Resistance in Clinical Acinetobacter baumannii Isolates from Hospitalized Patients in Iran

Majdani, Raheleh; Zaeri, Zahra; Derakhshandeh, Abdollah; Sattarinezhad, Elahe; Motevasel, Maryam

year 19, Issue 5 (September - October 2025) Iran J Med Microbiol 2025, 19(5): 330-340 | Back to browse issues page

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Majdani R, Zaeri Z, Derakhshandeh A, Sattarinezhad E, Motevasel M. Relationship between Biofilm Formation and Antibiotic Resistance in Clinical Acinetobacter baumannii Isolates from Hospitalized Patients in Iran. Iran J Med Microbiol 2025; 19 (5) :330-340
URL: http://ijmm.ir/article-1-2633-en.html

Relationship between Biofilm Formation and Antibiotic Resistance in Clinical Acinetobacter baumannii Isolates from Hospitalized Patients in Iran

Raheleh Majdani¹

, Zahra Zaeri¹

, Abdollah Derakhshandeh²

, Elahe Sattarinezhad³

, Maryam Motevasel⁴

1- Department of Biology, Faculty of Basic Sciences, University of Maragheh, Maragheh, Iran
2- Department of Pathobiology, Faculty of Veterinary Medicine, Shiraz University, Shiraz, Iran
3- Department of Pharmacology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
4- Department of Medical Laboratory Sciences, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran , motevaselm10@gmail.com

Abstract: (332 Views)

Background and Aim: Acinetobacter (A.) baumannii is an opportunistic pathogen in humans, affecting immunocompromised patients and is becoming increasingly important as a hospital-acquired infection. These strains exhibit resistance to essential current antibiotics, posing a real health threat worldwide. The aim of this study was to investigate the relationship between biofilm formation and antibiotic resistance in clinical Acinetobacter baumannii isolates.
Materials and Methods: A total of 40 clinical isolates were collected from Iranian hospitalized patients. Disk diffusion method was performed to assess the antimicrobial resistance. Crystal violet staining was used to assess the biofilm-forming ability and polymerase chain reaction (PCR) was employed to determine the frequency of biofilm-related genes (bfmR, bfmS, pgaA, bap, ompA, csuE, and abaI). The relationship between biofilm-forming ability and resistance to antibiotics was statistically analyzed using Fisher's exact test and P≤0.05 was considered significant.
Results: All A. baumannii isolates were multidrug-resistant (MDR). The frequency of extensively drug-resistant (XDR) was 80%, and the rest were pan-drug-resistant (PDR). Most of the MDR isolates (85%) were strong biofilm formers, and the rest of them were moderate biofilm formers. All PDRs and 81.25% of XDRs formed strong biofilms. The bfmR, bfmS, pgaA, bap, and ompA genes were existed in all MDRs. The csuE and abaI genes were detected in 97.5% and 82.5% of MDRs, respectively. All XDRs carried csuE gene, and 90.62% possessed abaI gene. Among PDR isolates, 87.5% presented csuE gene, and 50% exhibited abaI gene.
Conclusion: The presence of biofilm-forming genes may be related to antibiotic resistance in clinical A. baumannii isolates, although a clone of PDR is evolving with strong biofilm-forming ability and lacking abaI gene.

Keywords: Acinetobacter baumannii, Biofilm, Extensively drug-resistant, Multidrug-resistant, Pan-drug-resistant

Type of Study: Original Research Article | Subject: Antibiotic Resistance
Received: 2025/06/10 | Accepted: 2025/09/20 | ePublished: 2025/11/11

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