Abstract: Objective To explore nosocomial infection and the distribution of pathogenic bacteria in intensive care unit （ICU） patients, and analyze the influencing factors of nosocomial infection in patients. Methods From January 2019 to December 2021, 2 348 patients hospitalized in the ICU of four hospitals in Nanjing were selected. Clinical data such as gender and age of the patients were collected, and 3 821 microbiological samples were cultured and identified. The factors affecting nosocomial infection were analyzed by univariate and multivariate analysis methods. Results A total of 231 patients were infected in the hospital, the infection rate was 9.84%. A total of 382 strains of non-repetitive pathogenic bacteria were detected, including 242 gram-negative bacteria （63.55%）, 95 gram-positive bacteria （24.87%）, and 45 fungi （11.78%）. Multivariate Logistic regression analysis showed that age<18 years old （OR=4.775）, age 60-75 years old （OR=4.426）, severity of disease ≥4 points （OR=4.818）, admission time in ICU ≥15 days （OR=6.134）, central venous intubation （OR=6.420）, tracheal intubation （OR=3.264）, urinary intubation （OR=5.711）, use of ≥2 antibiotics （OR=4.748）, surgery （OR=7.843）, and complicated with diabetes mellitus （OR=45.901） were risk factors for nosocomial infection in ICU patients. Conclusions The nosocomial infection of ICU patients is mainly caused by gram-negative bacteria, which is closely related to age, the severity of the disease, length of stay, central venous intubation, tracheal intubation, and other factors. Medical staff can prevent and control nosocomial infection by adhering to aseptic operation, environmental disinfection and purification, rational use of antibiotics, and other measures.

Key words: Intensive care unit, Pathogenic bacteria, Nosocomial infection, Influencing factor