45 CFR 75 (eCFR link) is HHS's (and thus CDC's) implementation of the OMB Uniform Guidance at 2 CFR 200.
As noted on About 2 CFR 200, HHS has taken the approach of codifying the Uniform Guidance (UG) in its entirety in a separate regulation. HHS needed to reserve sections within the regulation for future insertions, and this made it necessary to change the numbering scheme of the sections in the UG. So it's important for organizations that are subject to HHS's version of the guidance to cite the correct sections in 45 CFR 75.
HHS explains and describes these changes in its commentary on the (19 DEC 2014 FR publication of interim final rule (79 FR 75871 et seq.)). Note that HHS's commentary begins on page 75875 and the full text of 45 CFR 75 begins on page 75889 of 79 FR.