Treatment of Infectious Disease

Antimicrobial agents Chemical substances that either kill microbes or prevent their growth Term “antibiotic” means “destroyer of life: Often refers to drugs used to treat bacterial infections Can be either microbistatic or microbicidal Microbistatic-inhibits or prevents the growth of microbes Microbicidal-kills the microbe

Treatment of Bacterial Diseases These drugs target structural functions and metabolic characteristics of the bacteria. Can be grouped into categories based on mode of action

Mode of Action Inhibit cell wall synthesis Inhibit protein synthesis Inhibit nucleic acid synthesis Or inhibit some other chemical reaction

Penicillins Mode of action: interferes with cell wall snythesis Treats: ear infections, sepsis, wound infections, etc Important to take all of the prescribed medication

Cephalosporins Mode of action: interferes with cell wall synthesis Treats: skin and soft tissue infections, and can be used in place of penicillin if allergy is present

Tetracycline Inhibits protein synthesis Treats: H.pylori, skin infections, UTI’s and STD’s Can have severe side effects including interfering with bone formation in a developing fetus, also causes sun sensitivity

Erythromycin Inhibit protein synthesis Treats: endocarditis, rheumatic fever, and gonorrhea Can make skin more sensitive to sunlight Caution! can be toxic if used in high doses for prolonged periods of time

Rifampicin Inhibits RNA synthesis Treats: Tuberculosis Can stain contact lenses

Sulfonomides Interferes with nucleic acid synthesis Treats: kidney infections and other UTI’s Can have allergic reactions

Treatment of Viral Illnesses Drugs that inhibit viral infections are highly toxic to host cells because viruses use the host’s metabolism Most illnesses due to virus are treated symptomatically until the immune system eliminates the virus

Acyclovir Antiviral: Inhibits nucleic acid synthesis Treats: herpes simplex viruses including Herpes Zoster viruses

Amantadine Antiviral used to prevent or decrease the symptoms of influenza among those that are at risk Inhibit replication of virus

AZT Antiviral: Inhibits the HIV genome Treats the symptoms of HIV Patients are also prescribed proteases that interfere with the packaging of the HIV genome into virus particles

Treatment of Fungal and Parasitic Diseases Challenging due to the toxicity to human tissue These medication target the pathogens’ replicative pathway

Antifungal drugs Inhibit sterol synthesis or disrupt the cell membrane Treats: systemic fungal infections and histoplasmosis Can be toxic to human tissue Amphotericin B used for systemic fungal infections

Antihelminthic drugs Target adult worms that no longer replicate Mode of action: inhibit fundamental processes like muscle function Treats: helminth infectious in animals, trichinella spirialis and avermectins (lice)

Antiprotozoan drugs Malaria was successfully treated for years with Quinine(also Chloroquine) Recently, a certain species has become resistant to this drug In these areas, a combination of sulfonamide and pyrimethamine are used

Robert Koch 1870’s studied Anthrax Developed Koch’s Postulates: Because of this scientists identified the bacterial cause of many disease

Edward Jenner 1798 Jenner noticed patients who had a milder disease of cowpox were immune to smallpox. He scatched the skin of patients with cowpox to immunize against small pox

Louis Pasteur Used heat to sterilize culture media Pasteurization is named in his honor now used to kill bacteria in a variety of beverages

Joseph Lister Sprayed surgical rooms with aqueous phenol to reduce wound infection

Alexander Fleming Discovered substance in Penicillium mold killed staphylococcal bacteria, named it penicillin.

Antimicrobial Resistance What causes antimicrobial resistance? What responsibilities does the medical community have? How can the general public prevent the problem?

Resistance to Antimicrobal Agents Resistance to antimicrobals has been an ongoing problem for decades This phenomenon has existed since antibiotics were introduced by Alexander Fleming-Penicillin Many pathogens are gaining a resistance to multiple drugs

Resistance to Antimicrobal Agents Resistance to antimicrobals results from changing in genes or acquisition of genes This allows the pathogen to resist the mode of action of the drug