I believe that any good organic chemist must have strength in physical chemistry (both to excel in the field, plus it's typically a degree requirement), and physical chemists are well-informed of quantum mechanics (also typically a degree requirement, with at least an introduction to QM in most introductory chemistry courses in the unit about atomic bonding).
However, it's more plausible to believe the claim (re-interpreted) that many microbiologists don't have a strong foundation in organic chemistry or modern physics. Still, I'm skeptical that those who make it to a tenured professorship can still have these weaknesses, as I'm under the impression that the field is cross-disciplinary with collaborations with biochemists, who can then bring in their stronger background in chemistry (and thus organic chemistry, physical chemistry, and physics). Leading microbiologists (e.g. those tenured at MIT and other top institutions) who influence the field should also have familiarity with these subjects.