Prevalence of Carbapenemase Genes blaOXA-48, blaNDM, and blaIMP in Multidrug Resistant Pseudomonas aeruginosa and Klebsiella pneumoniae Clinical Isolates from University Hospital Sharjah, UAE

International Journal of Biomedicine 15(4) (2025) 731-735 http://dx.doi.org/10.21103/Article15(4)_OA14 ORIGINAL ARTICLE INTERNATIONAL JOURNAL OF BIOMEDICINE Antimicrobial Resistance Prevalence of Carbapenemase Genes blaOXA-48, blaNDM, and blaIMP in Multidrug Resistant Pseudomonas aeruginosa and Klebsiella pneumoniae Clinical Isolates from University Hospital Sharjah, UAE Hassan El Sharief1,2, Sara Mohamed Ali1, Salsabeel Mohamed1, Nours Abbas2, Mera Maher2, Praveen Kumar1, Salma Elnour1* Gulf Medical University, College of Health Science, Medical Laboratory Science Master’s Program. Ajman, United Arab Emirates 2 University Hospital Sharjah, Sharjah, United Arab Emirates 1 Abstract Background: Carbapenem-resistant Pseudomonas aeruginosa and Klebsiella pneumoniae are globally recognized as priority pathogens due to their association with multidrug resistance and limited therapeutic options. Carbapenemase genes, such as blaOXA-48, blaNDM, and blaIMP, play a central role in the dissemination of resistance. Methods and Results: This study investigated the prevalence and co-occurrence of these pathogens in 100 multidrug-resistant isolates collected from University Hospital Sharjah, between November 2024 and June 2025. PCR detection revealed blaOXA-48 as the most prevalent gene (66.7% in P. aeruginosa and 65.5% in K. pneumoniae), followed by blaIMP (44.4% and 38.2%), and blaNDM (15.6% and 23.6%). Co-occurrence of two or more genes was observed in over 30% of isolates, and a small proportion carried all three. Approximately one-quarter of isolates tested negative for these targets, indicating alternative mechanisms of carbapenem resistance. Conclusion: Our findings provide hospital-level molecular data from Sharjah that align with broader trends in the UAE, while highlighting the complexity of resistance-gene combinations. The results underscore the importance of ongoing molecular surveillance, monitoring of gene co-occurrence, and enhanced antimicrobial stewardship to mitigate the effects of multidrugresistant, Gram-negative infections.(International Journal of Biomedicine. 2025;15(4):731-735.) Keywords: β-lactamases • carbapenem resistance • metallo-beta-lactamase • infection control For citation: Sharief HEl, Ali SM, Mohamed S, Abbas N, Maher M, Kumar P, Elnour S. Prevalence of Carbapenemase Genes blaOXA-48, blaNDM, and blaIMP in Multidrug Resistant Pseudomonas aeruginosa and Klebsiella pneumoniae Clinical Isolates from University Hospital Sharjah, UAE. International Journal of Biomedicine. 2025;15(4):731-735. doi:10.21103/Article15(4)_OA14 Abbreviations CRE, carbapenem-resistant Enterobacterales; IMP, imipenemase; KPC, Klebsiella pneumoniae carbapenemase; MBLs, metalloβ-lactamases; NDM, New Delhi metallo-β-lactamase; VIM, Verona integron-encoded metallo-β-lactamase. Introduction The rapid emergence of multidrug-resistant (MDR) Gramnegative bacteria presents a significant global health challenge.1 Pseudomonas aeruginosa and Klebsiella pneumoniae are associated with a wide range of infections, including bloodstream infections, ventilator-associated pneumonia, urinary tract infections, and surgical site infections,2 which have earned them a place in the WHO’s list of substantial MDR pathogens in their priority list for 2024.3 Pseudomonas aeruginosa and Klebsiella pneumoniae possess the ability to acquire and disseminate β-lactamase genes, including carbapenemases that hydrolyze carbapenems, the last line of defence against multidrug-resistant Gram-negative infections. According to the Ambler molecular classification in 1980, β-lactamases are divided into four classes (A–D).4 Among them, classes A, B, and D harbour the clinically 732 H. El Sharief et al. / International Journal of Biomedicine 15(4) (2025) 731-735 most significant carbapenemases, while class C enzymes play an indirect role. Class A comprises serine carbapenemases such as Klebsiella pneumoniae carbapenemase (KPC) and, less commonly, GES-type enzymes, which are now globally disseminated in Enterobacterales.5 Class B includes the metalloβ-lactamases (MBLs), a zinc-dependent group represented by New Delhi metallo-β-lactamase (NDM), Verona integronencoded metallo-β-lactamase (VIM), and imipenemase (IMP), all of which confer resistance to nearly all β-lactams except monobactams.6,7 Class C enzymes, mainly AmpC-type cephalosporinases, are not highly efficient carbapenemases but can lead to carbapenem resistance when combined with porin loss or efflux mechanisms.8 Finally, class D enzymes, specifically the oxacillinases, encompass the clinically significant OXA48-like carbapenemases, which are now endemic in K. pneumoniae in the Middle East and North Africa.9,10 Recent surveillance indicates that the OXA-48 enzyme remains the most frequently detected carbapenemase globally, followed by NDM and KPC, while IMP variants continue to predominate in East Asia, particularly in Japan.11-13 In P. aeruginosa, carbapenemase-mediated resistance is also escalating, with blaVIM and blaOXA-48 being the most common, whereas blaIMP and blaNDM occur at lower frequencies but frequently co-exist, compounding resistance mechanisms.14 Longitudinal studies demonstrate a significant increase in blaNDM prevalence among carbapenem-resistant P. aeruginosa between 2021 and 2025, highlighting its expanding clinical impact.15-18 In the UAE, surveillance data confirm the growing clinical threat posed by carbapenem-resistant Enterobacterales (CRE). A retrospective national study analysing more than 14,500 isolates between 2010 and 2021 found that K. pneumoniae accounted for nearly half (48.1%) of all cases, followed by Escherichia coli (25.1%) and other Enterobacterales (26.8%). By 2021, resistance in K. pneumoniae was alarmingly high, reaching 67.6% for imipenem, 76.2% for meropenem, and 91.6% for ertapenem. blaNDM and blaIMP were detected across E. coli, K. pneumoniae, P. aeruginosa, and A. baumannii, often in combination with ESBL genes, while blaOXA-48 was notably absent.19 Understanding the local prevalence and interaction of carbapenemase genes is crucial for implementing effective infection control practices and antimicrobial stewardship programs. This study investigated the prevalence and cooccurrence of blaOXA-48, blaNDM, and blaIMP genes among MDR P. aeruginosa and K. pneumoniae isolates obtained from University Hospital Sharjah in the UAE. Offering insights into the genetic architecture of resistance in this high-risk setting. aeruginosa and 55 Klebsiella pneumoniae, were obtained from clinical specimens, including blood, urine, sputum, wound swabs, and other sterile body fluids. Identification and Antimicrobial Susceptibility Testing All isolates were identified and subjected to antibiotic susceptibility testing using the VITEK® 2 Compact system (bioMérieux, France). DNA Extraction Genomic DNA was extracted using the G-spin Total DNA Extraction Kit from iNtRON Biotechnology, Korea, according to the manufacturer’s instruction (...truncated)