Discussion

The prevalence found in this study is 10%, which is slightly higher than that reported by Al-Abdely et al. (2021) [8] as 8.6%. In contrast, studies conducted in other regions of Saudi Arabia show higher rates; for instance, Said et al. (2021) reported a prevalence of over 20% in Ha'il [9]. Klebsiella pneumoniae was the most prevailing CRE species, accounting for 81% of the total CRE isolates in our study. It is similar to the observations assessed by Al-Abdely et al. (2021), who reported the prevalence of this species in 90% of CRE isolates. Klebsiella pneumoniae remains the most common carbapenem-resistant pathogen worldwide [8]. There is a consistent pattern across Asia, Africa, and the Americas, driven mainly by the organism's remarkable ability to acquire and spread genes encoding for carbapenemases, including KPC, NDM, and OXA-48-like enzymes [10,11]. The strong association with nosocomial outbreaks and HAIs further solidifies its global predominance among carbapenem-resistant pathogens [12].

Among the currently circulating strains, NDM was the predominant carbapenemase gene detected (58%), followed by 23%, which harbored both OXA-48 and NDM, and 19%, which harbored OXA-48 alone. KPC, VIM, and IMP were not detected in these strains. Previous studies in Saudi Arabia reported OXA-48 in 58%, 81%, NDM in 20%, 42%, and both NDM and OXA-48 in 8%, 14%, respectively [8]. Al-Mohammadi et al. (2022) agreed with our results in having 45% NDM in carbapenem-resistant Klebsiella pneumoniae in Yemeni hospitals as reported in their study [13]. This regional alignment could be attributed to geographic proximity and population mobility across borders.

In our cohort, NDM-type carbapenemases predominated as the major resistance mechanism, which fits with the broader geographical pattern wherein NDM-producing Enterobacterales have become established throughout South Asia and the Middle East. In contrast, KPC producers constitute the main CRE burden in several settings in America and Europe–Latin America, including the United States, Brazil, and Greece, where they account for approximately three-quarters to nearly all CRE isolates [10]. OXA-48 and related enzymes are more frequently reported from North Africa and countries bordering the Mediterranean [10]. These observations support the observation that our local resistance profile fits into a regional NDM–OXA-48 axis rather than the KPC-dominated epidemiology seen elsewhere, and is likely influenced by region-specific clonal spread, antimicrobial use policies, and infection prevention capacity.

There was a similar age distribution in the multicentre Saudi study of Alraddadi et al., in 2022 as observed in our study, where the CRE infections tended to cluster among the older inpatients [14]. The clearest statistical signal in our analysis was for device- and care-related exposures. The review by Elhaj (2024) [15] and the meta-analysis by Singh et al. (2025) [16] both identified ICU stay, central lines, and urinary catheters as recurrent risk factors, observations that are in accordance with our findings. With few cases of CRE, particularly among populations with other health conditions, the absence of evidence should be interpreted with caution as an imprecise estimate, not as evidence for the absence of effect. Blood and urine accounted for comparable proportions of CRE isolates (42.3% [11/26] and 38.5% [10/26], respectively), differing by only one isolate; therefore, the study did not establish blood as a clearly predominant specimen source. The distribution nevertheless demonstrated both bloodstream and urinary presentations. Alraddadi et al. (2022) reported that nearly half of CRE infections (46.6%) were bloodstream infections [14]. Nassar et al. (2023) reported an even higher proportion of bacteremic presentations (53.4%), followed by urinary tract infections [17]. We did not systematically record patient-level outcomes such as length of stay, duration of ICU treatment, mortality, or treatment response.

The meta-analysis by Zhang et al. (2023) reported mortality exceeding 40% among ICU patients with CRE bacteremia, highlighting the potential severity of these infections [18].