Can antibiotics ever be needed for a cold?

No. If it's truly just a cold, the answer is no. It's a viral illness, and won't respond to antibiotics. You can sometimes go on to develop bronchitis or sinusitis, but studies show that antibiotics are of no benefit for acute bronchitis, and should only be used for sinusitis when it persists for a long time. Antibiotics are recommended for strep throat, but most sore throats aren't strep throats.