No, not all of them.
- Actinomycin is a polypeptide antibiotic and has a -mycin suffix
- Erythomycin and Azithromycin are macrolide antibiotics and have a -mycin suffix
- Rifamycins are not aminoglycosides and have a -mycin suffix
- Vancomycin is a glycopeptide antibiotic and has a -mycin suffix
Most probably, the suffix -mycin comes form the genus of bacteria from which those drugs were isolated (some modified after isolation);
Streptomyces
