Clinical Characteristics and Risk Factors of Carbapenem-Resistant Escherichia coli in Patients with Urinary Tract Infections: Development of a Predictive Nomogram.

BACKGROUND

Carbapenem-resistant Escherichia coli (CREC) is a growing threat in urinary tract infections (UTIs). This study aimed to analyze the clinical characteristics and risk factors of patients with CREC UTIs and to construct a prediction nomogram.

METHODS

This case-control study retrospectively analyzed clinical data of 162 patients with CREC UTIs (2018-2024). One hundred and forty-eight cases were matched 1:1 with non-CREC UTI controls by department, gender, and age (±1 year). Univariate and multivariate logistic regression analyses identified independent risk factors of CREC UTIs. R software was used to construct a prediction nomogram, followed by internal validation.

RESULTS

CREC urine isolation rate was 1.90% (162/8517). Among 162 CREC patients, 35.80% were male, the mean age was 60.21 ± 17.28 years. Patients' source departments included urology (42, 25.93%), outpatient clinics (23, 14.20%), and ICU (16, 9.88%). 56.2% of patients had underlying urinary tract diseases. CREC strains exhibited >90% resistance to most antibiotics. CREC group had significantly higher UTI reinfection rate than non-CREC group (P=0.002). Independent risk factors for CREC UTIs included recurrent UTIs (≥3 times per year), urinary system stone, surgical procedures (within 1 year), catheterization duration ≥7 days (within 3 months), ≥2 antibacterial drugs used pre-infection (within 1 month), and Carbapenems used pre-infection (within 1 month) (P < 0.05). The C-index of the nomogram constructed based on these six indicators was 0.868 (95% CI: 0.831-0.917), with a mean absolute error of 0.049 on the calibration curve.

CONCLUSION

Patients with CREC UTIs were predominantly middle-aged and elderly women. Most patients had underlying urinary system diseases. CREC strains exhibited multidrug resistance. Patients had a significantly higher recurrence rate of UTIs. A nomogram based on recurrent UTIs, urinary stone, surgical procedures, urinary catheterization duration ≥7 days, ≥2 antibacterial drugs, and Carbapenems pre-infection displayed high accuracy and consistency in predicting CREC UTIs.