Antimicrobial Agents

Antimicrobial agents Antibiotics – bacteria Antifungals – fungus Antiprotozoans – protozoa Antihelminths – worms

Infection It has only been in the last 150 years that we have realized that infections were caused by other living organisms residing in the host

Infection Localized – limited to one area like skin, eyes, ears or mucosa Systemic – infection involves the body

Infectious Disease There are many, many disease processes that are caused by infection There are many, many terms to describe infection

Microbiology The study of these microbes is covered in microbiology (microscopic biology).

Basic Micro Terms for Antibiotics Bacteriostatic – prevent bacteria reproduction Bacteriolytic – cause bacteria death

The age of antibiotics Although there have been cultures that used plants and minerals to treat infectious diseases for centuries Our understanding of infectious disease and the scientific use of antibiotics is less than a century old

Many horrible diseases are no longer killing the masses worldwide Learn the history of infectious disease and the human suffering it has caused

Proper sanitation and clean water have done more to combat infectious disease than anything else

Sulfonamides Sulfonamide drugs were the first antimicrobial drugs Paved the way for the antimicrobial revolution in medicine

Sulfonamides The first sulfonamide was trade named Protonsil, which is a prodrug of an active sulfonamide. Experiments with Prontonsil began in 1932 in the laboratories in the laboratories of Bayer AG.

Sulfonamides Prontonsil was the first medicine ever discovered that could effectively treat a range of bacterial infections. It had no effect at all in a test tube or petri dish, exerting its antibacterial action only in live animals.

Sulfonamides Antibacterial sulfonamides act to prevent a key step in folate synthesis Since folate is necessary for cells to synthesize nucleic acids… Preventing folate acid synthesis prevents cells from dividing

Sulfonamides Because the sulfonamide antibacterial prevent reproduction of the bacteria they are…

Sulfonamides Folate is synthesized in mammalian cells, it is a dietary requirement This explains the selective toxicity in bacteria

Sulfonamides Sulfacetamide as topical for bacterial conjunctivitis Silver sulfadiazine cream for burn wounds

Bactrim Septra SMX/TMP Sulfamethoxazole with Trimethoprim are used in combination as a potent antibiotic combination Trimethoprim is also a folate synthesis inhibitor

Sulfonamide Sulfonamides led to the development of many sulfa-based drugs: Sulfonylureas – for diabetes mellitus Thiazide diuretics – for hypertension

Sulfonamide Unfortunately, sulfonamides cause allergic reactions in nearly 5% of the population Is a leading cause of a drug induced Stevens-Johnson syndrom – a type of allergic reaction

Stevens-Johnson syndrom

Polyketides Polyketides are metabolites from bacteria, fungi, plants and animals.

Polyketides Ancient wisdom gave us the knowledge that certain plants and molds were helpful in preventing what we call infection

Penicillin It has been known since the ancients that certain molds had healing properties Modern scientific investigation of these properties emerged as early as 1875.

Penicillin Although the antimicrobial properties of penicillin were well accepted Mass production of penicillin was difficult until 1940s. It was common procedure to collect the urine from patients being treated so that the penicillin could be isolated and reused.

Penicillin Thanks to a lot of researchers, and a moldy cantaloupe in Peoria, Illinois… By 1944, PCN was in full mass production

Penicillin Penicillin was used to treat Gonorrhea before but now it is no longer being used since the bacteria evolved to resist the antibiotic

However… Some bacteria, which had never caused infections before penicillin, emerged as pathogens…

Beta-lactam antibiotics Penicillins Cephalosporins Carbapenems