I'm not a PD or on an adcom, but I doubt that any allo program would take an applicant without a USMLE. It's the very basis for applicant selection and not taking it would suggest either that you were ignorant of the requirement or lacked sufficient motivation to complete this basic step. I'm trying to think of a way to find this out and I can't imagine that programs would specifically mention this in their application materials or websites. You'll probably have to contact program administrators/PDs directly to ask.
To the OP, your score is very low. It is nearly 2 SD below the mean, and barely above passing (is 188 still the passing bar?). It is always possible that you'll nail step 2 (statistically, this is unlikely) and that you'll secure enough interviews to get in, but it would be prudent to have a back-up (even just a number of prelim/transitional programs to do an internship from which you could potentially apply for a PGY2 spot that might open up someplace). This isn't meant to sound harsh or discouraging, but banking on the "anything's possible, just go for it" plan doesn't leave all your options open. Preparing yourself now to apply to LOTS of programs and to have a back up in a less competitive specialty will help you match into SOMETHING come match day. Graduating medical school without post-graduate training would be a miserable feeling.