Although Aquaphor has Panthenol in it, it is not a cream, and it is approximately 99% petroleum in the form of petroleum jelly, and mineral oil. Creams are around 50% water give or take depending on the particular one, and so the petroleum in them absorbs more quickly into the skin instead of sitting on top creating a non-breathable barrier as well as a lovely place for dirt and bacteria to hang out and enter your new tattoo through the wet scab that normally would protect you if it were dry.
As far as the science of staph is concerned, everyone carries their own strain of staph bacteria at all times. Some staph infections are caused by coming into contact with someone else's staph and being unable to fight it off, but plenty are actually just flare-ups of our own bodies staph. Any time there is a wound to a person's body, the chances of the bodies staph bacteria blooming into a full blown infection are increased. Staph flourishes in a warm, moist, airless environment which is exactly what you create when you put a layer of petroleum on top of your new tattoo. If you've ever had a bunch of red bumps, or even small whiteheads form on or around a new tattoo, that was your bodies staph flaring up.
I've had a few clients over the years have no infection problems with their tattoos when using lotion as a moisturizer, but then develop staph outbreaks within a day after trying Aquaphor.
As far as what I know of staph and how it works, the knowledge came from reading a paper written by researchers at Johns Hopkins university about staph, and the most effective cleaning agent to use in the hospital to reduce infections from cross-contamination.
One last thing. You wouldn't use Vaseline on a new tattoo would you? People quit using that stuff on their tattoos decades ago because of the regular infections that came along with the use of it. Aside from being slightly less sticky, and having a very small percentage of other added chemicals added, Aquaphor is nearly identical. A little bit of all vegetable oil based lotion is much better for not only your tattoo, but for your personal health overall.