FDA recall classifications are defined by the likelihood and severity of health consequences:

• Class I: Reasonable probability that use/exposure will cause serious adverse health consequences or death (e.g., microbial contamination of a sterile product or a life-threatening wrong drug situation).

• Class II: May cause temporary or medically reversible adverse health consequences, or where the probability of serious adverse consequences is remote.

• Class III: Not likely to cause adverse health consequences; often labeling or packaging issues that do not impact safety/efficacy.

For nystatin suspension:

• Bacterial contamination (A) or fungal contamination (C) represents a clinically significant contamination with potential for harm—this aligns with Class I (or Class II in some limited contexts depending on product/route), but certainly not Class III.

• Wrong active ingredient present (B) (e.g., presence of carbamazepine) is a serious error that can cause significant harm and is typically Class I.

• Incorrect lot number on the label (D) is a labeling defect not likely to cause adverse health consequences, aligning with a Class III recall.