AIRBORNE BACTERIAL CONTAMINATION IN INTENSIVE CARE UNITS OF A TERTIARY CARE HOSPITAL

Abstract

This study aimed to assess the level of airborne bacterial contamination in intensive care units (ICUs) of a tertiary-care hospital using a descriptive study design. A total of 120 air samples were collected from 10 ICU units at two sampling locations (patient bedside and nursing station) during three time periods (before, during, and after patient care activities). Bacterial concentrations were reported as colony-forming units per cubic meter (CFU/m³) and presented as median values with interquartile ranges (IQR). The results demonstrated variability in airborne microbial load across ICU units. The Intermediate Medicine Female (IMF) unit exhibited the highest median concentration (104.17 CFU/m³; IQR 54.17-233.34), followed by the Stroke Unit (95.83 CFU/m³; IQR 41.67-141.67), whereas the Cardiovascular and Thoracic Intensive Care Unit (CVT ICU) had the lowest median level (25.00 CFU/m³; IQR 8.33-66.67). No statistically significant difference was observed between sampling locations (p = .300). However, significant differences were identified across sampling periods (p = .006), with the highest median concentration recorded during patient care activities (66.67 CFU/m³). Gram-positive bacteria predominated, particularly coagulase-negative Staphylococci, Micrococcus spp., and Bacillus spp., whereas Acinetobacter baumannii complex was detected at low levels. The number of individuals present in the area was positively correlated with airborne bacterial concentration (ρ = 0.403, p < .001). These findings indicate that airborne microbial load in ICUs varies according to unit characteristics, clinical activity intensity, and occupancy density.

Keywords: Airborne Bacterial Contamination, Intensive Care Unit, Indoor Air Quality, Healthcare-Associated Infections