Final answer:
Broad-spectrum antibiotics significantly disrupt the normal flora by killing beneficial bacteria, leading to possible superinfections and resistance issues, which is why narrow-spectrum antibiotics are favored initially.
Step-by-step explanation:
False, broad-spectrum antibiotics do not have a minimal effect on the normal flora. In fact, they can significantly disrupt the balance of the microbiota by killing both harmful and beneficial bacteria. This disruption can lead to an overgrowth of antibiotic-resistant species like Clostridium difficile, causing severe health issues such as chronic diarrhea. Broad-spectrum antibiotics therefore increase the risk of superinfections, which occur when protective microbiota is destroyed, allowing resistant pathogens to proliferate and cause secondary infections. For this reason, physicians try to use narrow-spectrum antibiotics first to minimize damage to the microbiota and prevent antibiotic resistance.