I am fairly certain that no lady would share a condom
Therefore, I doubt that this would be a legitimate concern. We are professionals after all, and are very aware of health risks and possible implications of various acts. Changing the gear between switching patners should be as routine as changing it would be if the lady was wearing lipstick and just provided oral.
No reasonable or educated lady would endanger herself (or you). And I feel fairly confident in saying that all of us fit into that category.
