Purpose: To assess the potential of bacterial transmission using felt-tipped marker pens on forehead skin before cataract surgery.
Methods: A total of 64 marker pens taken from clinical stock were tested. Forty-eight new pens were cultured in the laboratory. They were first left to desiccate for 0, 4, and 16 h, then dipped into solutions of 0.5 Macfarlane's concentration of coagulase negative staphylococci (CNS), methicillin-resistant Staphylococcus aureus (MRSA) and coliforms, and transferred onto the culture medium after 5, 10, 30, and 120 min intervals of exposure to air. A further 16 pens were collected after routine clinical use for 5 working days and cultured.
Results: Positive cultures were observed in 100% of pens at 0 min, and 44.4% at 5 min after the organism was exposed to air. Escherichia coli showed least transmissibility with no growth in all plates after 5 min of exposure. Only MRSA showed heavy growth after 10 min of exposure. No pattern emerged with reference to the length of time; each pen was left to desiccate. No growth was observed in the cultures of all 16 marking pens after clinical use.
Conclusions: The potential for transmission of bacteria through felt-tipped marker pens has not been explored in cataract surgery. This study demonstrated that a theoretical risk of transmission exists in a laboratory setting, and survival times of the bacteria decreased with time. This suggests that the interval in which patients are marked with the same pen may play a role in bacterial transmission.