Factors associated with clinical classification of BALF mNGS-detected Enterococcus faecium as infection rather than colonization in ICU patients

Objective To identify clinical factors associated with infection rather than colonization of pulmonary infection,when Enterococcus faecium is detected by mNGS in bronchoalveolar lavage fluid. Methods Clinical data were retrospectively analyzed from 64 ICU patients admitted to Changsha First Hospital between March 2025 and March 2026 in whom E. faecium was detected in BALF by mNGS. According to integrated clinical diagnosis and etiological assessment, patients were categorized into an infection group ( n = 32) and a colonization group ( n = 32). Baseline characteristics, invasive procedures, resistance profiles, and in-hospital outcomes were compared between groups. Factors associated with E. faecium pneumonia were identified using binary logistic regression. Results Age, sex, diabetes mellitus, hypertension, cerebrovascular disease, chronic liver disease, chronic kidney disease, inherited metabolic disease, history of abdominal surgery, malnutrition, consciousness status, indwelling gastric tube, tracheal intubation/tracheostomy, prolonged hospitalization with broad-spectrum antibiotic exposure, hospital stay ≥6 days, and in-hospital outcomes did not differ significantly between the two groups (all p > 0.05). In univariate analysis, dysphagia, concomitant viral infection, indwelling urinary catheterization, and central venous catheterization were more frequent in the infection group, whereas coronary heart disease, underlying pulmonary disease, and glucocorticoid use were more frequent in the colonization group (all p < 0.05). Exploratory multivariable analysis identified concomitant viral infection, indwelling urinary catheterization, and central venous catheterization as factors associated with infection rather than colonization of pulmonary infection (all p < 0.05). According to the mNGS reports, resistance genes were detected in 8 patients (25.0%) in the infection group, including vanM + vanA in 3 patients, vanA in 1 patient, and vanM in 4 patients. In the colonization group, resistance genes were detected in 4 patients (12.5%), all of whom carried vanM + vanA. These genes are primarily associated with glycopeptide resistance. Conclusion Concomitant viral infection, indwelling urinary catheterization, and central venous catheterization may be important clinical clues for interpreting the significance of BALF mNGS-detected E. faecium . When E. faecium is detected in BALF by mNGS, its etiological significance should be determined by integrating clinical manifestations, risk factors, imaging findings, and conventional microbiological evidence. Antimicrobial therapy should be individualized according to resistance gene detection, phenotypic susceptibility testing, infection site, and patient-specific organ function.