Abstract
Purpose: :
To investigate the amount of bacterial dispersal associated with speech in various conditions during a simulated intravitreal injection.
Methods: :
Fifteen healthy volunteers each read a 5 minute script over an open blood agar plate in the following conditions: without a facemask, without a facemask with the face turned away from the plate and with a facemask. The volunteer then stood in silence for 5 minutes over an open blood agar plate. Total number of colony forming bacteria per plate were counted and identified. The Kruskal-Wallis test was used for statistical analyses.
Results: :
Without a facemask, 12 of 15 plates had growth of at least 1 bacterial colony (mean=10.5 colonies per plate, range=0-63). When a facemask was worn, 3 of 15 plates had growth (mean=0.3 colonies per plate, range=0-2). With the face turned away from the plate, 10 of 15 plates had growth (mean=1.8 colonies per plate, range=0-6). When the volunteer stood in silence, 4 of 15 plates had growth (mean=0.33 colonies per plate, range=0-2). Statistical analysis demonstrated significantly lower bacterial colony counts in the "facemask" and "silence" conditions compared to the "no facemask" condition (p=0.0004 and p=0.0008 respectively). There were also significantly lower bacterial colony counts in the "facemask" and "silence" conditions compared to the "face turn" condition (p=0.008 and p=0.017 respectively). Bacterial colony counts were not significantly different among the conditions "facemask," "silence," and "room control."
Conclusions: :
Wearing a facemask or remaining silent significantly decreases culture plate contamination from talking during simulated intravitreal injection setting. Physicians performing intravitreal injections should be aware of these patterns of bacterial dispersal associated with speech and consider either wearing a facemask or minimizing speech.
Keywords: injection • microbial pathogenesis: clinical studies