OBJECTIVE To understand the current status of antimicrobial agent usage intensity (AUD) of antibiotics, carbapenems (CB) and isolation rates of carbapenem-resistant gram-negative bacteria (CRGNB) and explore the effect of CB on hospital-associated CRGNB infections.

METHODS A retrospective analysis was conducted on antimicrobial agent usage and clinical data of the patients who were hospitalized in Nantong University Affiliated Hospital from 2023 to 2024. The antimicrobial usage patterns, CB-AUD and isolation rates of CRGNB were statistically analyzed. Additionally, the clinical data from 1933 confirmed hospital-acquired infection cases from 2023 to 2024 were retrospectively analyzed, and the patients were classified into two groups based on CRGNB resistance: the CRGNB-infected group with 376 cases and the non-CRGNB-infected group with 1557 cases. The risk factors for CRGNB infections were identified.

RESULTS In the two years, the overall utilization rate of antimicrobial drug and AUD fluctuated every six months (P < 0.05).The overall define daily dose system (DDDs) and AUD of the three CBs (meropenem, imipenem/cilastatin and biapenem) increased every six months (P < 0.05). The overall drug resistance rate of gram-negative bacilli to CB decreased every six months (P < 0.05). The logistic regression analysis showed that the duration of use of CB and combined use of antibiotics were the risk factors for the CRGNB infections (with the OR values, 1.445, 2.479, 1.958, respectively, all P < 0.05).

CONCLUSIONS The overall use of CB is on the rise. The use of CB, especially the duration of CB, increases the probability of CRGNB infection. Therefore, it is necessary for the hospital to strengthen the monitoring of CB-AUD and supervision of CB.