Final answer:
Superinfection occurs when antibiotics kill protective normal flora, allowing resistant pathogens to proliferate, such as with a Clostridium difficile infection after broad-spectrum antibiotic use. The normal microbiota, which play a vital role in health, are disrupted, paving the way for opportunistic pathogens to cause secondary infections.
Step-by-step explanation:
A superinfection occurs when the antibacterial treatment intended for a preexisting infection inadvertently kills the protective normal biota (flora), allowing another pathogen, which is resistant to the antimicrobial, to proliferate and cause a secondary infection. This disruption in the balance of normal flora can lead to a decrease in 'good' bacteria which otherwise help in keeping pathogenic microbes in check. Clostridium difficile infection is a classic example of such a superinfection, typically occurring after the use of broad-spectrum antibiotics which kill the healthy gut bacteria, enabling C. difficile to overgrow and cause symptoms like severe diarrhea and other gastric problems.
A normal human body has colonies of bacteria that are beneficial or non-harmful, known as normal microbiota or normal flora. These organisms play an essential role in the processes such as digestion, immunity, and preventing colonization by harmful pathogens. However, when antibiotics or other factors disrupt these colonies, opportunistic pathogens may take advantage of the situation and cause an infection.