[Impact of active surveillance for carbapenem-resistant organisms on healthcare-associated infections and clinical prognosis of patients in intensive care unit: a propensity score-matching historical cohort study].

OBJECTIVE

To evaluate the impact of active surveillance for carbapenem-resistant organisms (CRO) on healthcare-associated infections and clinical prognosis of patients in intensive care unit (ICU), and to provide real-world clinical evidence for developing scientific CRO active surveillance protocols in medical institutions.

METHODS

A prospective intervention study with a post-hoc retrospective historical control cohort design was conducted. ICU inpatients at the General Hospital of Ningxia Medical University from January 1, 2024 to December 31, 2025 were enrolled. The routine testing group comprised patients hospitalized from January 1 to December 31, 2024, who underwent routine microbiological testing with only retrospective chart review (690 cases). The CRO active surveillance group comprised patients hospitalized from January 1 to December 31, 2025, who received active CRO surveillance within 24 hours of ICU admission (608 cases). The active surveillance protocol involved collecting nasal swabs, rectal swabs, sputum specimens, and secretions or drainage fluids from existing wounds or drainage sites, which were inoculated onto chromogenic media. Patients with positive CRO results were considered colonized or infected with CRO and placed under contact precautions; those with negative results continued to receive standard precautions. Propensity score matching (PSM) at a 1 : 1 ratio was used to control for confounding factors including age, sex, acute physiology and chronic health evaluation II(APACHE II), severity of surgical insult (surgical grade×number of surgeries), and durations of mechanical ventilation, central venous catheterization, and urinary catheterization, with a caliper value of 0.02. After matching, the two groups were compared for CRO healthcare-associated infection incidence and clinical outcomes (in-ICU mortality, treatment abandonment rate, and improvement-to-discharge rate).

RESULTS

A total of 634 patients in the CRO active surveillance group underwent active surveillance (608 of whom met inclusion criteria), with a CRO positivity rate of 22.4% (142/634). A total of 1 298 patients were enrolled, including 690 in the routine testing group and 608 in the CRO active surveillance group. After PSM, 477 pairs were successfully matched, with 477 cases in the routine testing group and 477 cases in the CRO active surveillance group. After matching, baseline characteristics were well balanced and comparable between the two groups [all standardized mean differences (SMD)<0.1, all P>0.05]. After PSM, there was no statistically significant difference in CRO nosocomial infection incidence between the CRO active surveillance group and the routine testing group [2.3% (11/477) vs. 2.5% (12/477), both P>0.05]. However, the CRO active surveillance group had significantly lower in-ICU mortality [2.1% (10/477) vs. 4.6% (22/477)] and treatment abandonment rate [8.6% (41/477) vs. 18.0% (86/477)] compared with the routine testing group (both P<0.05), and a significantly higher improvement-to-discharge rate [89.3% (426/477) vs. 77.4% (369/477), both P<0.05].

CONCLUSIONS

In ICUs with well-established basic infection prevention and control measures, implementation of CRO active surveillance combined with contact isolation did not further reduce the incidence of CRO healthcare-associated infections. However, it significantly improved patient outcomes by enabling early warning and guiding precise antimicrobial therapy.