Patient- and care-related factors associated with central line-associated bloodstream infection in adult intensive care units: a retrospective matched case-control study at a tertiary referral center

Central line-associated bloodstream infection (CLABSI) is an important preventable healthcare-associated infection in intensive care units (ICUs). This study evaluated patient- and care-related factors associated with CLABSI and described the causative microorganisms in adult ICU patients. This single-center retrospective matched case-control study included adult patients admitted to nine ICUs at Namazi Hospital, Shiraz, Iran, between January 2018 and December 2023. Among 3,200 eligible records, 205 patients with confirmed CLABSI were compared with 412 non-CLABSI controls selected by 1:2 nearest-neighbor matching on age and sex. Associations with CLABSI were evaluated using multivariable binary logistic regression. Prior to model building, multicollinearity was assessed using the variance inflation factor (VIF) and tolerance. Independent risk factors included medical hospitalization type (adjusted OR = 2.428, p < 0.001), general ICU admission (adjusted OR = 3.068, p < 0.001), invasive mechanical ventilation within 24 hours (adjusted OR = 1.971, p = 0.013), pre-ICU antibiotic use (adjusted OR = 2.768, p = 0.008), pre-ICU hospital length of stay (adjusted OR = 1.047/day, p = 0.011), elevated BMI (adjusted OR = 1.055/kg/m 2 , p = 0.008), and elevated core temperature (adjusted OR = 1.662/°C, p = 0.012). Protective factors included direct home admission (adjusted OR = 0.613, p = 0.021), ICU admission from the operating theatre/recovery (adjusted OR = 0.647, p = 0.048), higher Glasgow Coma Scale score (adjusted OR = 0.950, p = 0.032), and higher platelet count (adjusted OR = 0.998, p = 0.024). Klebsiella species (22.2%) and Acinetobacter species (13.4%) were the predominant pathogens. CLABSI risk in adult ICUs reflects a convergence of pre-ICU healthcare exposure, illness severity, invasive interventions, and patient physiology. These findings provide an empirical foundation that may inform future research on risk stratification and prevention strategies for CLABSI.