Analysis of Antimicrobial Use and Mortality Factors in Patients with Drug-Resistant K. pneumoniae at Mukdahan Hospital

Abstract

Purposes: To analyze the situation of carbapenem-resistant bacterial infections and to identify factors associated with mortality in patients infected with drug-resistant K. pneumoniae.

Study design: A retrospective cohort study.

Materials and Methods : The study included a total of 149 patients, of whom 42 had infections caused by drug-resistant K. pneumoniae. Data were retrospectively collected from medical records of patients with antimicrobial-resistant infections who had received approval for restricted antimicrobial use between January 1 and December 31, 2023. The research instrument was a data collection form, which was validated for content validity (IOC = 0.84). Data analysis employed descriptive statistics, including frequency, percentage, mean, and standard deviation, as well as inferential statistics using the Chi-square test and Independent t-test.

Main findings : Among 149 patients, 51 (34.28%) were infected with carbapenem-susceptible organisms, showing a mortality rate of only 5.88%, with appropriate drug selection in 92.16% and correct dosing in 88.24%. The mean hospital stay in this group was 17.0 ± 10.1 days. In contrast, 98 patients (65.77%) with carbapenem-resistant infections had a significantly higher mortality rate of 25.51%, appropriate drug selection in only 74.49%, and correct dosing in merely 24.49%, with a mean hospital stay of 37.7 ± 29.5 days. Statistical analysis revealed significant differences in both mortality (Chi-square test, p = .007) and length of hospital stay (Independent t-test, p < .001). The most common resistant pathogen was carbapenem-resistant Acinetobacter baumannii (CRAB) (51.01%), while the highest mortality was observed in carbapenem-resistant Klebsiella pneumoniae (CRKP) (35.71%). Mortality was significantly associated with the appropriateness of dosing and administration (p = .02). Patients receiving PK/PD-optimized regimens, such as meropenem high-dose prolonged infusion or appropriate colistin loading dose, had lower mortality. The most frequently prescribed regimen was colistin plus meropenem (65.31%) and colistin-related adverse events were observed in 22.78% of cases, mostly nephrotoxicity.

Conclusions and recommendation : Carbapenem-resistant infections are associated with high severity, significantly increased mortality, and prolonged hospital stay. Revision of the hospital CPG is warranted, with sulbactam recommended as first-line therapy for CRAB and ceftazidime-avibactam (restricted formulary, category J2) as first-line therapy for CRE where applicable. Updating the Drug Utilization Evaluation (DUE) process is essential to improve treatment outcomes, reduce mortality, and minimize long-term healthcare costs.