Genetic characteristics and risk factors of extended-spectrum β-lactamase-producing in Chinese intensive care unit: a prospective molecular epidemiology study.

In this 4-month-long prospective observational study, we explored the colonization rate of extended-spectrum β-lactamase-producing (ESBL-EC) in the patient and ward environment of an intensive care unit (ICU). Additionally, we evaluated the risk factors for colonization and analyzed genomic characteristics and modes of transmission of isolates. Clinical samples were collected from patients and the environment to isolate and screen strains. ESBL-EC from the strains was identified using ESBL confirmation and antibiotic susceptibility tests and subsequently characterized using whole-genome sequencing. Clinical data were collected and further analyzed. Among the 214 isolates, 82 were ESBL-EC, with CTX-M-14 being the dominant enzyme, followed by CTX-M-55 and CTX-M-15. The predominant sequence types (STs) among the 82 ESBL-EC strains were ST10, followed by ST131 and ST1193. Using multiple logistic regression, exposure to third-generation cephalosporins and a special class of anti-positive-bacterial drugs, as well as albumin and enteral nutrition, were high-risk factors for ESBL-EC colonization. The clonal transmissions of ESBL-EC in the ICU were predominantly attributed to the movement of healthcare workers. More effective interventions and active screening are needed to prevent and control ESBL-EC colonization.IMPORTANCEThe increasing prevalence of extended-spectrum β-lactamase-producing (ESBL-EC) has made drug-resistant bacterial infections rise, endangering people's health and causing socioeconomic burdens. We conducted an ESBL-EC screening program for patients and ward environments in an intensive care unit (ICU). The aim was to describe the molecular characteristics of ESBL-EC and the risk factors for ESBL-EC colonization. In our hospital, the colonization rate of ESBL-EC remained high. The dominant sequence type was ST10, which might be considered a strain of notable concern, possibly causing future outbreaks. However, ST131 and ST1193 should also be considered because they were associated with the majority of the ESBL-EC isolates found. Notably, CTX-M-14 gene screening should be considered in medication guidance because it is the main ESBL enzyme. Owing to the high transmission rate of ESBL-EC, effective interventions and active screening are critical for preventing and controlling its spread, guiding clinicians in rational antibiotic use.