Final answer:
For antibiotics affecting the bacterial cell wall, intramuscular or intravenous injections are preferred to ensure direct bloodstream delivery, especially if high plasma levels are needed quickly for serious infections.
Step-by-step explanation:
The proper injection technique for administering antibiotics that affect the bacterial cell wall is typically either intramuscular injection or intravenous injection. This preference for parenteral routes, like intravenous or intramuscular administration, ensures that the antibiotic is directly delivered into the bloodstream, bypassing the gastrointestinal (GI) tract where the drug may not be easily absorbed. Antibiotics such as amoxicillin and doxycycline are effective in the early stages of an infection and they can be given intravenously in later stages when high plasma levels are required quickly to treat serious infections. For home administration, oral antibiotics could be more convenient for treating systemic infections, but in a healthcare setting where immediate high plasma levels of the drug are necessary, the intravenous route is preferred.