SURGICAL FACE MASKS AND DOWNWARD DISPERSAL OF BACTERIA

The ability efface masks to prevent forward dispersal of bacteria is o ffset by the possibility that they may increase vertical shedding of b acteria from the face during facial movement. To investigate this, a b lood agar plate was placed 30 cm directly below the lips of 20 volunte ers who were encouraged to talk for 20 min while moving their heads fr om side to side, without a face mask for the first 5 min and then with a standard, soft pleated face mask for the subsequent 15 min. The aga r plates were changed at 5-min intervals. Analysis of the number of ba cterial colonies grown on each agar plate showed a statistically signi ficant reduction in the median number of colonies cultured per plate w hen the mask was worn. Our results suggest that for procedures lasting less than 15 min, the operator should wear a face mask, particularly when the face is in close proximity to the operative field and the nee d for speaking is anticipated.