I don't think it is bad. Not everyone has the opportunity to have their names in a published paper. Whatever research you have done, just be able to explain it well if asked.
You do realize that most people who apply to MD/PhD programs have no publications, right? And I mean top programs (Harvard, Yale, Hopkins). My friend got into Penn's MSTP last year. No pubs.
That.I really can't speak for how an admissions committee would view your application...
But in undergraduate research having your name tagged on a publication is usually due to the generosity of the PI rather than the researcher's talent or intellect, unless you were heavily involved in preparing the manuscript and formulating the hypothesis.