Objective To actively screen the dynamic colonization of Enterobacteriaceae in the gastrointestinal tract of tumor patients and explore the homology between carbapenem-resistant Enterobacteriaceae (CRE) colonized in the gastrointestinal tracts of these patients and the bacteria causing bloodstream infections, to provide meaningful reference data for diagnosis and treatment by clinicians.

Methods A total of 32 strains of gram-negative bacilli were isolated from 353 intestinal specimens of tumor patients at The First Affiliated Hospital of Henan University of Science and Technology from December 2021 to November 2022. The bacterial identification instruments VITEK 2 Compact, a carbapenemase detection kit using colloidal gold immunochromatography, and polymerase chain reaction (PCR) were used to detectdrug resistance genes and phenotypes. Pulsed-field gel electrophoresis (PFGE) was used to analyze and compare the homology between CRE strains in the intestinal tract of patients and pathogenic microorganisms causing bloodstream infections.

Results Among the 32 strains of Gram-negative bacilli screened from the gastrointestinal tract of cancer patients, 6 strains (1.6%, 6/353) were carbapenem-resistant Klebsiella pneumoniae (CRKp). All six CRKp strains harbored blaKPC gene. The proportion of CRE is 3.3% (12/353). Bloodstream infection occurred in 2 patients with intestinal colonization of Klebsiella pneumoniae, which was caused by the same CRKp strain as intestinal colonization.

Conclusions The proportion of CRE intestinal colonization in tumor patients was not high; however, under certain circumstances, CRE colonized in the intestines of tumor patients can cause ectopic infections else where in the body, including the bloodstream, which should be closely monitored. The findings indicate the importance of increased attention to critically ill patients who have undergone multiple hospitalizations with long hospitalization times, as well as early screening for intestine-colonizing microorganisms and rational regulation of the antibiotic usage.