Comparison of two sampling methods of detection of bacterial contamination in the hospital environment: moistened swabs versus RODAC agar plate

Abstract

Abstract Purpose: This study aimed to investigate the efficiency of two different sampling methods (swabbing, and RODAC (replicate organism detection and counting) agar plate) in terms of detection of bacterial contamination, and their suitability as monitoring methods for partition curtains and other medical textiles. Methods:A total of 24 beds were selected by stratified random sampling .The swabbing technique and RODAC agar plates were the chosen sampling methods. The colony forming units were calculated and colony morphologies and strains on the plates were observed and identified after culturing. Results:A total of 192 samples collected. Of them, 161 pathogenic strains were isolated via the swabbing technique; 309 pathogenic strains were isolated using the RODAC agar plates. The swabbing technique had a higher detection rate for Gram-positive bacteria (P = 0.0004) , while RODAC agar plate had a higher detection rate for Gram-negative bacteria (P = 0.72).The detection of bacterial contamination rates using the swabbing technique was superior to that of the RODAC agar plate method (P < 0.001). Conclusions: The swabbing technique offers more advantages in terms of detection of bacterial contamination rates and Gram-positive bacteria, while the RODAC agar plate is more sensitive to the inspection of Gram-negative bacteria.