Epidemiology and clinical outcomes of carbapenamase-producing organism (CPO) colonization: a tertiary care center experience in Saudi Arabia

BACKGROUND: The global emergence of carbapenem-resistant Enterobacterales (CRE) infections has critically reduced therapeutic options and are associated with high mortality. While CRE epidemiology has been extensively studied worldwide, data on intestinal CRE colonization in Saudi Arabia remain limited. This study aims to determine the prevalence of intestinal Carbapenem Producing Organisms (CPO) carriage, characterize carbapenemase genes, and evaluate associated clinical outcomes among hospitalized patients. METHODS: Carba-R test. Demographics, clinical data, carbapenemase gene types, and clinical and microbiologic outcomes were collected from electronic medical records. Associations between carbapenemase gene types, clinical characteristics, and outcomes were analyzed using the chi-square test and t-tests. (p < 0.05). RESULTS: Among 6405 screened patients, 778 carbapenemase-producing isolates were detected (12.1%), OXA-48 was most prevalent (49.7%), followed by NDM (23.6%), OXA-48 + NDM co-producers (15.2%), KPC (4.8%), VIM (5.0%), and IMP-1 (1.7%). Most patients were ≥ 65 years (52.3%), and 84.3% were ICU inpatients. Common comorbidities included hypertension (57.5%) and diabetes mellitus (57.5%). Recent antibiotic exposure occurred in 73.3% of patients. The 30-day mortality rate was 24.6%, with no significant difference among carbapenemase types (p = 0.44). Subsequent infection within 90 days occurred in 29%, significantly associated with enzyme type (p = 0.001), highest among KPC (48.6%) and OXA-48 + NDM (38.1%) producers. Persistent colonization occurred in 29.3% of cases (p = 0.006), particularly among VIM (46.2%) and KPC (40.5%) producers. CONCLUSION: OXA-48 and NDM were the dominant carbapenemase genes among intestinal CPO carriers in this tertiary care hospital. High rates of subsequent infection and mortality highlight the clinical importance of CPO colonization, especially in the ICU and elderly populations. Strengthened infection control practices and active surveillance are essential to limit CPO spread and improve patient outcomes. CLINICAL TRIAL NUMBER: Not applicable.