Surviving superbugs: Epidemiology, clinical impact, and resistance trends in carbapenem-resistant non-fermenters

Background: The worldwide spread of carbapenem-resistant non-fermentative gram-negative bacilli (CR-NFGNB) has posed an urgent public-health threat, especially in healthcare institutions. The purpose of this study was to define the epidemiological, clinical outcome and antimicrobial resistance pattern of infections caused by CRNFGNB in a secondary care hospital. Materials and Methods: We retrospectively reviewed clinical isolates of CRNFGNB from various clinical samples submitted to Sohar Hospital, Oman from January 2017–December 2021. Bacterial identification and antimicrobial susceptibility testing were done in accordance with Clinical and Laboratory Standards Institute (CLSI) standards. Univariate analyses determined risk factors for mortality through chi-square tests and Fisher's exact tests, with significance level of p < 0.05. Results: Among 1,201 NFGNB isolates, 233 (19.4%) demonstrated carbapenem resistance, predominantly hospital-acquired (76.0%). The isolates were recovered from 201 patients (61.2% male; median age 55 years). Acinetobacter baumannii exhibited the highest carbapenem resistance rate (59.3%, 144/243), followed by Pseudomonas aeruginosa (7.9%, 75/944). Carbapenemresistant A. baumannii (CRAB) demonstrated extensive resistance to aminoglycosides (98.6%), fluoroquinolones (100%), and β-lactam/β-lactamase inhibitor combinations (100%), while maintaining susceptibility to colistin (100%) and tigecycline (93.3%). Significant mortality predictors included mechanical ventilation (OR: 4.8, p<0.001), central venous catheterization (OR: 3.7, p < 0.001), COVID-19 with secondary bacteremia (p < 0.001), hemodialysis (p = 0.002), and end-stage renal disease (p = 0.025). Conclusion: The high prevalence of carbapenem resistance, especially in A. baumannii in our hospital settings, coupled with limited therapeutic options and significant mortality in vulnerable populations, requires urgent implementation of robust antimicrobial stewardship, infection prevention strategies, and investment in therapeutic development to mitigate this emerging threat in secondary care facilities.