Of the 2284 cases who underwent MDRO screening, the median age was 59.0 years (interquartile range, IQR 45.0–72.0), and 650 (28.5%) were females (Table 1). Positive cases for MRSA, CRE, CRAB, and VRE screening on ICU admission were observed in 72 (3.2%), 39 (1.7%), 15 (0.7%), and 4 (0.2%) patients, respectively.

The most common cause of ICU admission was postprocedural or postoperative monitoring, accounting for 1341 cases (58.7%), followed by acute respiratory failure with 386 cases (16.9%). Patients who were admitted to cardiology, surgical departments, and medical departments were 1256 (55.0%), 306 (13.4%), and 722 (31.6%), respectively. Approximately one-third of patients had a history of admission, and 8.8% underwent surgery within the past year. 16% had at least one catheter, and 21% received antibiotics within the last 3 months. Only 2.8% had any of the 4 MDROs previously.

The positive group had a higher median age and APACHE II scores than the negative group (Table 1). The positive group was more likely to be admitted to medical departments with acute respiratory failure and sepsis from general wards. Five MDRO risk factors were more prevalent in the positive group, including admission history, surgical history, use of any catheter, previous antibiotic exposure, and previous MDRO carriage history.

The CRE and CRAB-positive groups demonstrated similar characteristics to the MDRO-positive group (Additional file 1: Table S1). In contrast, the MRSA-positive group predominantly consisted of patients admitted to the cardiology department for postoperative monitoring. These MRSA-positive patients had fewer prior admissions, less frequent catheter usage, and a lower history of previous antibiotic exposure than the CRE and CRAB-positive groups.

The use of tracheostomy or endotracheal tubes, previous antibiotic exposure, previous CRE or CRAB carriage history, and admission to the medical department were related to positive CRE or CRAB screening, with adjusted odds ratios of 20.017 (95% CI: 8.003–50.065, p < 0.001), 3.691 (95% CI: 1.413–9.640, p = 0.008), 13.329 (95% CI: 5.597–31.741, p < 0.001), and 6.601 (95% CI: 1.366–31.907, p = 0.019), respectively (Table 2). The adjusted odds ratios of PVD and liver disease were also 4.704 (95% CI: 1.433–15.444, p = 0.011) and 3.933 (95% CI: 1.078–14.358, p = 0.038), with association with CRE or CRAB carriage. Admission history, surgical history, and stroke did not show significant association with CRE or CRAB carriage.

On the contrary, when repeating the analysis on MRSA, prior MRSA carriage history and liver disease were only associated with positive MRSA screening (adjusted odds ratio of 12.262; 95% CI: 4.982–30.184, p < 0.001 and 4.247; 95% CI: 1.455–12.395, p = 0.008, respectively).

Tailored screening utilizing the six CRE or CRAB risk factors detected all cases (53/53) with positive multidrug-resistant Gram-negative bacilli, requiring 882 tests, constituting 38.6% of all tests. However, for MRSA, the tailored screening approach detected only 43.1% (31/72) of MRSA-positive cases.