After hair transplant, is it necessary to take a antibiotics? (like after lipo or implants surgery)

It is not necessary to take antibiotics after a hair transplant surgery in general.  However your doctor may have a specific reason or a regimen.

Although we give a dose of antibiotic just before and after each hair transplant there is no evidence to show that it needs to be continued.

Actually there is no need to use antibiotics after HT for a couple of days or a week.. I give one dose before and one dose after hair restoration surgery to my patients and think that much is enough .