Comparative analysis of colistin minimum inhibitory concentration detection methods and risk factors for multidrug-resistant organism in intensive care units and high dependancy units: Implications for infection control practices

Objectives The primary objective of the study was to compare the effectiveness of different methods (broth microdilution [BMD], colistin agar test [CAT], colistin disc elution [CDE], and Vitek) in detecting colistin resistance among clinical isolates. The secondary objective was to analyze risk factors associated with colistin-resistant organisms in intensive care unit (ICU) and high-dependency unit (HDU) settings. Material and Methods A total of 65 colistin-resistant isolates from various clinical samples were utilized. The resistant organisms were predominantly found in ICUs and HDUs. Colistin minimum inhibitory concentration (MIC) was determined using BMD, CAT, CDE, and the Vitek system. The sensitivity of each method was compared. Additionally, risk factor analysis was conducted to identify factors contributing to MDRO infections. Results The analysis revealed that BMD and Vitek methods demonstrated 100% sensitivity in detecting colistin resistance. The CAT method showed 96.92% sensitivity, ranking it as the second-best method, while the CDE method exhibited 70.76% sensitivity. Among the resistant organisms, Klebsiella pneumoniae (n=51) was most frequently encountered. Risk factor analysis indicated that long-term hospital stays and immunocompromised conditions in ICU patients increased the susceptibility to multidrug-resistant organisms (MDROs) infections. Conclusion The emergence of colistin resistance poses a serious threat to public health, particularly in ICUs and HDUs. Accurate detection of colistin resistance is vital for appropriate antibiotic therapy and infection control. This study demonstrates that while BMD and Vitek methods offer the highest sensitivity, CAT also provides reliable results and can be used in clinical practice. The findings highlight the need for ongoing surveillance, stringent infection control measures, and robust antimicrobial stewardship programs (AMSP) to combat the spread of MDROs and improve patient outcomes. Implementing rigorous infection prevention and control practices, as recommended by the US Centers for Disease Control and Prevention (CDC), can significantly mitigate the risks associated with MDROs.