Risk factors for colistin-resistant gram-negative bacterial infections

Colistin resistance constitutes a serious threat both clinically and in term of public health currently. The most common risk factors for colistin resistance are polymyxin and carbapenem use. Receiving healthcare services, prolonged hospital and intensive care unit stays, invasive device use, and comorbidities are other reported risk factors. This study aimed to examine and evaluate the demographic characteristics, infection-related risk factors, and mortality status of patients diagnosed with colistin-resistant gram-negative bacterial infection. Between 1 December 2018 and 1 December 2023, 199 patients hospitalized in the wards and ICUs of Süleyman Demirel University Research and Practice Hospital and diagnosed with colistin-resistant gram-negative microorganism infections were determined as case group. One hundred ninety-nine cases were included in the case group, and 208 cases with infections caused by colistin-susceptible microorganisms during the same period were included in the control group. The demographic characteristics of the patients, possible risk factors associated with the development of colistin-resistant gram-negative bacterial infection in terms of patient, healthcare, and antibiotic use, and mortality were examined. In the case group, colistin-resistant microorganisms were identified as 56.3% Klebsiella pneumoniae and 43.7% Acinetobacter baumannii, while in the control group, they were identified as 72.6% Acinetobacter baumannii and 27.4% Klebsiella pneumoniae. Cerebrovascular disease, blood product use, antibiotics used in the last three months, prior infection with multidrug-resistant microorganisms, hospitalization in the ICU, tracheostomy, and use of colistin, imipenem, and glycopeptide antibiotics were significant risk factors for the development of colistin-resistant gram-negative bacterial infection in the multivariate analysis. The study, the most significant modifiable risk factor was identified as the use of broad-spectrum antibiotics. In the ongoing battle against antimicrobial resistance, it is imperative that hospitals adhere to rigorous monitoring of their antimicrobial susceptibility profiles, meticulous identification of risk factors, and the implementation of infection control measures to ensure the rational utilisation of antibiotics.