Citation: Al-Sheboul, S.A.; Al-Moghrabi, S.Z.; Shboul, Y.; Atawneh, F.; Sharie, A.H.; Nimri, L.F. Molecular Characterization of Carbapenem-Resistant Acinetobacter baumannii Isolated from Intensive Care Unit Patients in Jordanian Hospitals. Antibiotics 2022, 11, 835. https://doi.org/10.3390/ antibiotics11070835 Academic Editor: Mehran Monchi Received: 3 June 2022 Accepted: 16 June 2022 Published: 21 June 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). antibiotics Article Molecular Characterization of Carbapenem-Resistant Acinetobacter baumannii Isolated from Intensive Care Unit Patients in Jordanian Hospitals Suhaila A. Al-Sheboul 1, *, Salam Z. Al-Moghrabi 1 , Yasemin Shboul 1 , Farah Atawneh 1 , Ahmed H. Sharie 2 and Laila F. Nimri 1 1 Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid 22110, Jordan; szalmoghrabi11@ams.just.edu.jo (S.Z.A.-M.); yashboul@just.edu.jo(Y.S.); farah.hatawneh@gmail.com (F.A.); nimri01@just.edu.jo (L.F.N.) 2 Faculty of Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan; ahalsharie16@med.just.edu.jo * Correspondence: sashboul@just.edu.jo; Tel.: +962-797411589 Abstract: Acinetobacter baumannii is a common cause of healthcare-associated infections (HAI) world- wide, mostly occurring in intensive care units (ICUs). Extended-spectrum beta lactamases (ESBL)- positive A. baumannii strains have emerged as highly resistant to most currently used antimicro- bial agents, including carbapenems. The most common mechanism for carbapenem resistance in this species is β-lactamase-mediated resistance. Carbapenem-hydrolyzing class D oxacillinases are widespread among multidrug-resistant (MDR) A. baumannii strains. The present study was conducted to determine the presence and distribution of bla OXA genes among multidrug-resistant A. baumannii isolated from ICU patients and genes encoding insertion sequence (IS-1) in these isolates. Addition- ally, the plasmid DNA profiles of these isolates were determined. A total of 120 clinical isolates of A. baumannii from various ICU clinical specimens of four main Jordanian hospitals were collected. Bacterial isolate identification was confirmed by biochemical testing and antibiotic sensitivity was then assessed. PCR amplification and automated sequencing were carried out to detect the presence of bla OXA-51 , bla OXA-23 , bla OXA-24 , and bla OXA-58 genes, and ISAba1 insertion sequence. Out of the 120 A. baumannii isolates, 95% of the isolates were resistant to three or more classes of the antibi- otics tested and were identified as MDR. The most frequent resistance of the isolates was against piperacillin (96.7%), cephalosporins (97.5%), and β-lactam/β-lactamase inhibitor combinations an- tibiotics (95.8%). There were 24 (20%) ESBL-producing isolates. A co-existence of bla OXA-51 gene and ISAba1 in all the 24 ESBL-producing isolates was determined. In addition, in the 24 ESBL-producing isolates, 21 (87.5%) carried bla OXA-51 and bla OXA-23 genes, 1 (4.2%) carried bla OXA-51 and bla OXA-24 , but all were negative for the bla OXA-58 gene. Plasmid DNA profile A and profile B were the most common (29%) in ESBL-positive MDR A. baumannii isolates while plasmid DNA profile A was the most common in the ESBL-negative isolates. In conclusion, there was an increase in prevalence of MDR-A. baumannii in ICU wards in Jordanian hospitals, especially those having an ESBL phenotype. Thus, identification of ESBL genes is necessary for the surveillance of their transmission in hospitals. Keywords: Acinetobacter baumannii; ICU; multidrug resistance genes; ESBL; plasmid DNA profile; Oxa carbapenems; insertion sequence; Jordan 1. Introduction Acinetobacter baumannii is a Gram-negative coccobacillus that is an aerobic, nonmotile, catalase-positive, and oxidase-negative pathogen. A. baumannii is an opportunistic pathogen in humans, affecting mainly people with compromised immune systems, and is becoming increasingly significant as a nosocomial infection [1]. A. baumannii normally inhabits mu- cous membranes, skin, and soil [1]. The organism is not fastidious in its growth requirement Antibiotics 2022, 11, 835. https://doi.org/10.3390/antibiotics11070835 https://www.mdpi.com/journal/antibiotics