Comparative Performance of Contact Plate Metod and Swab Method for Surface Microbial Contamination on Medical Fabrics

Abstract

Abstract Background: The contact plate method is widely accepted and used in various fields where hygiene and contamination levels are crucial. Evidence regarding the applicability of the contact plate method for sampling fabric microbial contamination levels in real medical environments was limited.This study aimed to assess the applicability of the contact plate method for detecting microbial contamination on medical fabrics in a real healthcare environment, thereby providing a benchmark for fabric microbial sampling methods. Methods: In a level three obstetrics ward of a hospital, twenty-four privacy curtains adjacent to patient beds were selected for this study. The contact plate and cotton swab method were used to collect microbial samples from the curtains on the 1st, 7th, 14th, and 28th days after they were hung. The total colony count on each curtain surface was calculated, and microbial identification was performed. Results: After excluding the effects of time, room type, and curtain location on the detected microbial load, the linear mixed-effects model analysis showed that the contact plate method yielded lower colony counts compared to the cotton swab method (P<0.001). However, the contact plate method isolated more microbial species than the cotton swab method (P <0.001). The predominant microbial species isolated from both methods were gram-positive bacteria (78.22%), followed by fungi (14.05%). The top three detected bacteria were Staphylococcus epidermidis (24.59%), Micrococcus luteus (23.42%), and Staphylococcus hominis (21.08%). Furthermore, the microbial load on curtains in double-occupancy rooms was lower than those in triple-occupancy rooms (P = 0.021), and the microbial load on curtains near windows was lower than that near doors (P = 0.004). Conclusion: The results showed that the contact plate sampling technique is more suitable for investigating hospital infection outbreaks and identifying specific pathogens on contaminated medical fabrics than the cotton swab method.