What is the difference between bactericidal drugs and bacteriostatic drugs?

A. Bactericidal and bacteriostatic are used interchangeably.
This statement is incorrect. Bactericidal and bacteriostatic have distinct meanings in pharmacology and microbiology. Bactericidal means the drug kills bacteria, whereas bacteriostatic means the drug inhibits the growth of bacteria without killing them.

B. Bactericidal drugs are directly lethal to bacteria, and bacteriostatic drugs work to slow bacterial growth but do not cause cell death.
This statement is correct. Bactericidal drugs directly kill bacteria, leading to their death. Bacteriostatic drugs inhibit the growth of bacteria without causing their immediate death. Both types of drugs play different roles in the treatment of bacterial infections.

C. Bacteriostatic drugs are directly lethal to bacteria, and bactericidal drugs work to slow bacterial growth but do not cause cell death.
This statement is incorrect. It confuses the roles of bactericidal and bacteriostatic drugs. Bactericidal drugs directly kill bacteria, while bacteriostatic drugs inhibit bacterial growth without immediate cell death.

D. A bactericidal drug can cause death to the host, whereas a bacteriostatic drug only affects bacteria.
This statement is incorrect. Both bactericidal and bacteriostatic drugs primarily affect bacteria, not the host. The difference lies in how they affect bacteria: bactericidal drugs kill bacteria directly, and bacteriostatic drugs inhibit their growth.

A. Delayed hypersensitivity reaction: This type of hypersensitivity reaction, also known as Type IV hypersensitivity, involves a delayed response by the immune system and is mediated by T cells. It does not necessarily involve a failure of self-tolerance.

B. Antibody-mediated reaction: This type of hypersensitivity reaction, also known as Type II hypersensitivity, involves antibodies targeting specific antigens on cell surfaces, leading to cell destruction. It doesn't directly indicate a failure of self-tolerance but rather an immune response against specific cells or tissues.

C. Autoimmune reaction: In autoimmune reactions, the immune system fails to recognize certain body tissues or substances as "self," leading to an immune response against the body's own cells or tissues. This results from a breakdown in self-tolerance, where the immune system mistakenly targets its own body.

D. Immediate hypersensitivity reaction: This type of hypersensitivity reaction, also known as Type I hypersensitivity, involves an immediate response by the immune system to an allergen. It includes conditions like allergies and anaphylaxis, where the immune system reacts strongly to substances that are normally harmless. This response does not necessarily indicate a failure of self-tolerance but rather an exaggerated response to specific antigens.