Final answer:
Narrow-spectrum antibiotics target specific bacteria, preserving normal flora and reducing resistance risk. They are chosen based on the infection, pathogen susceptibility, and patient status, considering the medication's selective toxicity, bacteriostatic or bactericidal nature, and spectrum of activity.
Step-by-step explanation:
Narrow-spectrum antibiotics are antimicrobial drugs that target specific types of bacteria, often either gram-positive or a limited number of gram-negative species, and are designed to minimize collateral damage to the host's normal microbiota. When the causative agent of an infection is known, the ideal antibiotic is narrow-spectrum, which can more effectively target the pathogen and reduce the likelihood of developing antibiotic resistance. Narrow-spectrum antibiotics are typically preferred over broad-spectrum antibiotics in order to avoid the negative effects of broad-spectrum antibiotic use, such as superinfection or the development of resistance. Selective toxicity is a crucial characteristic of an effective antimicrobial drug, which ensures that the drug selectively inhibits or kills microbial targets while causing minimal harm to the host. Depending on various factors, such as the specific pathogen, its susceptibility to drugs, and the patient's condition, physicians may opt to use bacteriostatic (inhibiting bacterial growth) or bactericidal (killing bacteria) drugs.