What O'Rourke said. Never single yourself out in melee. Stay with your group.
But also look for the single enemies and the standouts of your targeted group, don't run directly at someone aiming a gun at you, and try put yourself on the opposite side of your target from their friends. Nothing like getting stabbed in the back.
Also, keep in mind that bayonets have a decent reach, but they're still not overly hard to back out of reach from and/or sidestep if you're quick.