The Spread of Insertion Sequences Element and Transposons in Carbapenem Resistant Acinetobacter baumannii in a Hospital Setting in Southwestern Iran

Zahra Hashemizadeh; Gholamreza Hatam; Javad Fathi; Fatemeh Aminazadeh; Hossein Hosseini-Nave; Mahtab Hadadi; Nafiseh Hosseinzadeh Shakib; Sodeh Kholdi; Abdollah Bazargani

doi:10.3947/ic.2022.0022

The Spread of Insertion Sequences Element and Transposons in Carbapenem Resistant Acinetobacter baumannii in a Hospital Setting in Southwestern Iran

Infect Chemother. 2022 Jun;54(2):275-286. doi: 10.3947/ic.2022.0022. Epub 2022 Jun 2.

Authors

Zahra Hashemizadeh¹, Gholamreza Hatam², Javad Fathi^{1

3}, Fatemeh Aminazadeh¹, Hossein Hosseini-Nave⁴, Mahtab Hadadi¹, Nafiseh Hosseinzadeh Shakib¹, Sodeh Kholdi¹, Abdollah Bazargani⁵

Affiliations

¹ Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
² Basic Sciences in Infectious Diseases Research Center, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
³ Student Research Committee, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
⁴ Department of Microbiology and Virology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran.
⁵ Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran. bazargania@sums.ac.ir.

Abstract

Background: Acinetobacter baumannii is one of the most important hospital pathogenic bacteria that cause infectious diseases. The present study aimed to determine the frequency of carbapenem resistance genes in association with transposable elements and molecular typing of carbapenem-resistant A. baumannii bacteria collected from patients in Shiraz, Iran.

Materials and methods: A total of 170 carbapenem-resistant A. baumannii isolates were obtained from different clinical specimens in two hospitals. The minimum inhibitory concentrations (MIC) of imipenem were determined and the prevalence of OXA Carbapenemases, Metallo-β-lactamases genes, insertion sequences (IS) elements, and transposons were evaluated by the polymerase chain reaction (PCR) method. Finally, molecular typing of the isolates was performed by the Enterobacterial Repetitive Intergenic Consensus-PCR method.

Results: The MICs ranged from 16 to 1,024 µg/mL for imipenem-resistant A. baumannii isolates. Out of the 170 carbapenem resistant A. baumannii isolates, bla_OXA-24-like (94, 55.3%) followed by bla_OXA-23-like (71, 41.7%) were predominant. In addition, A. baumannii isolates carried bla_VIM (71, 41.7%), bla_GES (32, 18.8%), bla_SPM (4, 2.3%), and bla_KPC (1, 0.6%). Moreover, ISAba1 (94.2%) and Tn2009 (39.2%) were the most frequent transposable elements. Furthermore, (71, 44.0%) and (161, 94.7%) of the ISAba1 of the isolates were associated with bla_OXA-23 and bla_OXA-51 genes, respectively. Besides (3, 1.7%), (1, 0.6%) and (5, 2.9%) of bla_OXA-23 were associated with IS18, ISAba4, and ISAba2, respectively. Considering an 80.0% cut off, clusters and four singletons were detected.

Conclusion: According to the results, transposable elements played an important role in the development of resistance genes and resistance to carbapenems. The results also indicated carbapenem-resistant A. baumannii bacteria as a public health concern.

Keywords: Acinetobacter baumannii; Carbapenem-resistant A. baumannii; Insertion sequence; OXA Carbapenemase; Transposon.

Grants and funding

97.17642/Shiraz University of Medical Sciences/Iran