Prevalence and clinical outcomes of Carbapenemase-Producing Enterobacterales (CPE) colonization in patients with solid organ malignancies: a prospective study.

PURPOSE: To evaluate the prevalence of carbapenemase-producing Enterobacterales (CPE) colonization in patients with solid organ malignancies and investigate its association with severe infection, infection free survival, and mortality through prospective follow-up. METHODS: This single-center, prospective, observational study (July 2024-July 2025) included adult patients with lung, genitourinary, or gastrointestinal cancers at Gazi University Hospital. Rectal swabs were screened using chromogenic agar, and isolates were identified by MALDI-TOF MS. Meropenem susceptibility was determined via disk diffusion. Carbapenemase genes (OXA-48, NDM, KPC, VIM, IMP) were detected using an in-house multiplex PCR. All patients were followed for six months. RESULTS: Among 269 patients, the CPE colonization prevalence was 9.7% (n=26). E. coli and K. pneumoniae were the predominant isolates (46.2% each), with OXA-48 being the most frequent gene (84.6%), followed by NDM (11.5%). No significant differences were found between CPE-colonized and non-colonized patients regarding severe infection rates (34.6% vs 35.8%, p=0.904), infection-free survival (p=0.314), or mortality at 30, 90, and 180 days (p=0.481, p=0.519, and p=0.239). Among colonized patients, the rectal colonizing strain was phenotypically concordant with the causative pathogen of subsequent severe infection in 15.4% (n=4) of the cases. The median time to infection was 12 days (IQR, 6-15 days). CONCLUSIONS: Gastrointestinal CPE colonization in patients with solid organ malignancies was primarily driven by OXA-48-producing E. coli and K. pneumoniae. Although colonization did not significantly increase the overall risk of severe infection or mortality in this cohort, further large-scale, multicenter studies are needed to identify specific high-risk subgroups.