Lecture 4: Vaccination & Drug Resistance

What is drug resistance?

The ability of an organism to resist the growth-suppressing or microbicidal effects of particular antimicrobial agents.

What historical event marked the introduction of sulfonamides?

Sulfonamides were introduced in the mid 1930s, leading to staphylococcal resistance within a few years.

When was penicillin introduced and what was its impact?

Penicillin was introduced in the early 1940s, with staphylococcal resistance demonstrated in 1941.

What are some consequences of antibiotic resistance?

Treatment failure, increased hospital mortality, longer hospital stays, decreased quality of life, and higher costs.

Why are hospitals particularly problematic for antibiotic resistance?

Due to compromised patient populations, antibiotic selection pressure, and failure of hygiene and sanitation.

What factors influence drug resistance?

Dosage, duration and compliance, route of administration, type of organism, and interaction with other organisms.

What is the sequence of susceptibility in organisms?

Susceptible -> Persistent -> Resistant.

What are some mechanisms of antibiotic resistance?

Alteration of target molecules, enzymatic degradation of antibiotics, exclusion from cell entry, and active efflux.

How can antibiotic resistance be prevented?

Public education, accurate diagnosis, restriction on antimicrobial availability, and infection prevention programs.

What are the two major classes of immunization?

Passive immunization (preformed antibodies) and active immunization (host's immune system response).

What is the goal of active immunization?

To protect an individual from infection or from products produced during an infection.

Why are childhood vaccines given multiple times over a 5-year period?

To ensure passive immunity, multiple responses, and improved response to individual vaccines.

What are the types of active immunization vaccines?

Living (heterologous, modified live, vector) and non-living (killed, purified antigens, DNA/RNA).

What are the advantages of living vaccines?

Fewer doses required, no adjuvants needed, less chance of hypersensitivity, and relatively cheap.

What are the advantages of non-living vaccines?

Stable on storage, unlikely to cause disease through reversion, and unlikely to cause secondary disease.

What is the process of attenuation in modified live vaccines?

Modifying an organism so it can grow transiently in the host but not cause disease.

How are killed (inactivated) vaccines produced?

By killing the organism using heat or chemical methods, requiring several re-vaccinations.

What is a subunit vaccine?

A vaccine that uses an expression system to mass produce an antigenic protein.

How do DNA/RNA vaccines work?

They insert genetic information into the host's cells to express antigenic peptides/proteins.

What is the significance of vaccines in controlling infectious diseases?

Vaccines are the most efficient and cost-effective method of controlling infectious diseases.