Which of the following complaints by a man taking gentamycin would be most indicative that he is experiencing ototoxicity?

A. The patient stops taking the drug when he or she begins to feel better:

This choice refers to the common habit where patients discontinue their prescribed medication once they start to feel improvement in their symptoms, even if they haven't completed the full course of treatment. This premature cessation of medication can leave some microbes alive and potentially resistant to the antibiotic, allowing them to regrow and cause a recurrence of the infection.

B. The patient switches to multiple drug therapy from single drug therapy:

This choice describes a scenario where a patient switches from a single drug therapy to multiple drug therapy. While this may be a valid treatment approach in some cases, it is not directly related to the re-population and re-establishment of microbes causing an infection.

C. The patient uses OTC drugs prophylactically:

This choice involves patients using over-the-counter (OTC) drugs preventively without consulting a healthcare professional. While OTC drugs may have their own set of issues, such as contributing to antibiotic resistance, this behavior isn't specifically linked to the re-population and re-establishment of microbes causing an infection.

D. The patient increases the drug dosage when he or she perceives that the therapeutic effect of the drug is slowing down:

This choice describes a scenario where a patient independently increases the dosage of their medication without consulting a healthcare provider. While inappropriate dosage adjustments can lead to adverse effects, it doesn't directly address the re-population and re-establishment of microbes causing an infection.

A. An infection that is difficult to treat:

This choice describes a challenging infection but does not specifically capture the concept of a superinfection. While superinfections can indeed be difficult to treat, they are defined more specifically as secondary infections that occur due to disruption of the normal microbial flora during the treatment of an initial infection.

B. An infection caused by a weakened immune system:

This choice describes an infection that occurs due to a compromised or weakened immune system, which can indeed increase the risk of developing infections, including superinfections. However, it does not fully encompass the definition of a superinfection, which specifically involves the overgrowth of opportunistic pathogens after the disruption of normal microbial flora by antimicrobial treatment.

C. A secondary infection that occurs when microorganisms normally present in the body are killed by the drug:

This choice accurately describes what a superinfection is. It highlights the key concept that a superinfection is a secondary infection that arises when antimicrobial treatment disrupts or kills the normal microbial flora of the body, allowing opportunistic pathogens to overgrow and cause infection.

D. A drug-resistant infection:

This choice describes an infection caused by microorganisms that are resistant to the effects of antimicrobial drugs. While drug resistance is a significant concern in healthcare, it does not specifically define a superinfection. Superinfections can involve drug-resistant microorganisms, but they are not solely characterized by drug resistance; rather, they are secondary infections resulting from the disruption of normal microbial flora during antimicrobial treatment.