As a general matter, a petty offense is not a misdemeanor or visa versa. This are instead different classes of criminal offense.
Colo. Rev. Stat. 18-1-104(2) provides: "Each offense falls into one of eleven classes. There are six classes of felonies as defined in section 18-1.3-401, three classes of misdemeanors as defined in section 18-1.3-501, and two classes of petty offenses as defined in section 18-1.3-503"
That said, this offense may still appear on the background check so you will need to decide whether this offense was so minor that you want to go beyond the question asked and disclose this offense for the purpose of appearing forthright.
Disclaimer: This answer is for informational purposes only and does not constitute legal advice. This answer does not create an attorney-client relationship.