1. Proteins (The actual efflux pumps)

• Rule: Capitalized, NOT italicized.
• Examples: AdeABC, AdeIJK, CraA, AdeA, AdeB.
• Usage in your text: “Chloramphenicol was selected because previous studies have established AdeABC, AdeIJK, and CraA as the principal determinants of chloramphenicol resistance…” (Correct!)

2. Genes (The DNA sequences)

• Rule: Lowercase, italicized.
• Examples: adeABC, adeIJK, craA, adeA.
• Usage in your text: *”Expression of adeABC and adeIJK is controlled by transcriptional regulators…” or “The craA gene was upregulated…”*

3. Mutants / Deletions

• Rule: The Greek letter delta (Δ) is non-italicized, followed by the lowercase, italicized gene name.
• Examples: ΔadeAB, ΔadeIJ, ΔcraA.
• Usage in your text: *”Isogenic ΔadeAB and ΔadeIJ mutants were constructed…”*

Summary Checklist for your manuscript:

• If you are talking about the physical pump / protein complex $\rightarrow$ AdeABC, AdeIJK, CraA (No italics, capitalized)
• If you are talking about the DNA / gene / transcription $\rightarrow$ adeABC, adeIJK, craA (Italics, lowercase)
• If you are talking about the knockout strain $\rightarrow$ ΔadeAB, ΔadeIJ, ΔcraA (Delta non-italic, gene italicized & lowercase)

So, in the sentence you are asking about, leaving AdeABC, AdeIJK, and CraA as non-italicized is exactly correct!