Are any pathogens from feces infecting a cut in the anus considered "pretty contagious?"

Not very contagious: The bacteria that inhabit or infect an anal fissure or other anal wound are exactly the same ones that are normally present in feces. These bacteria are not highly contagious -- they can be transmitted by contact with feces or by personal contact with someone with poor toilet hygiene. But it's quite rare to catch such bacteria from other persons.