Research Article Genetic Diversity of Imipenem-Resistant Acinetobacter baumannii Infections at an Intensive Care Unit Amani Alnimr , 1 Aisha Alamri, 2 and Afnan Alsultan 2 1 College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia 2 College of Applied Medical Sciences Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia Correspondence should be addressed to Amani Alnimr; amalnimr@iau.edu.sa Received 20 October 2019; Accepted 31 December 2019; Published 21 February 2020 Academic Editor: Timothy E. Albertson Copyright © 2020 Amani Alnimr et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Introduction. Imipenem-resistant Acinetobacter baumannii (IRAB) represents a major clinical threat. Dissemination in critical care areas necessitates effective action measures including genotyping tools to study the clonality of these strains and trace their origin. e main aim of this study is to assess the genetic relatedness between IRAB isolates in our institution intensive care units (ICU) which are at a particular risk of outbreaks. Methods. Nonreplicate IRAB strains were serially collected over 3 years period (January 2016–December 2018) from patients admitted to the ICU. e isolates were phenotypically identified by a matrix- assisted laser desorption/ionization time-of-flight- (MALDI-TOF-) based system (VITEK MS), and their susceptibility was tested by the phenotypic-based VITEK 2 system. Molecular fingerprinting was performed by enterobacterial repetitive intergenic consensus (ERIC-PCR) followed by hierarchal clustering. e patterns were analysed by the software of BioNumerics package version 7.6.3 (Applied Maths, Belgium). Results. A total of eighty IRAB were isolated from 31 colonization and 59 infection sites in patients admitted to the ICU. Sixty-two samples were respiratory in origin (77.5%). e generated dendrogram revealed distinct patterns for majority (95%) of the strains. Meropenem maintained activity against 43.8% of the imipenem-resistant A. baumannii. Conclusion. Meropenem can be a therapeutic option for imipenem-resistant A. baumannii. e banding patterns propose that multiple IRAB strains are circulating in the intensive care units of the institution. Drivers for this diversity need to be evaluated including antimicrobial consumption. 1. Introduction Acinetobacter baumannii is a challenging nosocomial pathogen that has adapted to the hospital environment with a particular link to critical care units [1]. A global study covering seventy-five countries in five continents identified this pathogen as the fifth problematic organism implicated in nosocomial outbreaks and healthcare-associated infec- tions in critical care settings [2]. Infections by the multidrug- resistant (MDR) strains, defined as nonsusceptibility to an agent or more in three antimicrobial classes, as well as the extensively drug-resistant (XDR) strains of A. baumannii and defined as nonsusceptibility to at least one agent in all but two or fewer antimicrobial classes, are being increasingly reported in various parts of the world [3–5]. A recent systematic review that examined multiresistance in the organism over ten years has concluded that the postanti- biotic era for A. baumannii is expected [6]. Since carba- penems are considered a last option of treatment in invasive infections by A. baumannii, the emergence and spread of carbapenem-resistant Acinetobacter baumannii (CRAB) strains is a serious clinical threat [6–8]. Outbreaks are fre- quently reported with CRAB in healthcare institutions and particularly in critical care areas [9]. ese outbreaks can be caused by clonal dissemination or spread of genetically unrelated strains. e clonality in such a case can be ex- amined through molecular typing tools of which several methods have been used to type the organism in different settings [10]. PCR-based genotyping schemes are rapid, inexpensive, and user-friendly tools for typing A. baumannii in case of outbreaks. e primers in repetitive-element PCR Hindawi Critical Care Research and Practice Volume 2020, Article ID 3290316, 6 pages https://doi.org/10.1155/2020/3290316