Macrolide Antibiotics Comparison

·         Structure

·         Mechanism of action

·         Spectrum of activity

·         Indications and uses

·         Pharmacologic properties

·         Drug interactions

·         Key differences

·         Conclusions

·         Brief comparison

Cephalosporin Antibiotics

Cephalosporins are the most frequently prescribed class of antibiotics. They are structurally and pharmacologically related to the penicillins. Like the penicillins, cephalosporins have a beta-lactam ring structure that interferes with synthesis of the bacterial cell wall and so are bactericidal (which means that they kill bacteria).

Aminoglycosides

Aminoglycosides are derived from various species of Streptomyces.

In 1943, Selman Waksman, together with his co-workers, discovered that a fungus Streptomyces griseus produced an antibiotic substance which they named "streptomycin." Selman Waksman was awarded the Nobel Prize in Physiology or Medicine in 1952 for his discovery of streptomycin.

Macrolides

The macrolide antibiotics are derived from Streptomyces bacteria, and got their name because they all have a macrocyclic lactone chemical structure. The macrolides are bacteriostatic, binding with bacterial ribosomes to inhibit protein synthesis. Erythromycin, the prototype of this class, has a spectrum and use similar to penicillin. Newer members of the group, azithromycin and clarithyromycin, are particularly useful for their high level of lung penetration. Macrolide antibiotics are used to treat respiratory tract infections (such as pharyngitis, sinusitis, and bronchitis), genital, gastrointestinal tract, and skin infections.

Tetracyclines

Tetracyclines got their name because they share a chemical structure that has four rings. They are derived from a species of Streptomyces bacteria. Tetracycline antibiotics are broad-spectrum bacteriostatic agents, which inhibit bacterial protein synthesis. Tetracyclines may be effective against a wide variety of microorganisms, including rickettsia and amebic parasites.

Fluoroquinoloness

Fluoroquinolones (fluoridated quinolones) are the newest class of antibiotics. Their generic name often contains the root "floxacin". They are synthetic antibiotics, and not derived from bacteria. Fluoroquinolones belong to the family of antibiotics called quinolones. The older quinolones are not well absorbed and are used to treat mostly urinary tract infections. The newer fluoroquinolones are broad-spectrum bacteriocidal drugs that are chemically unrelated to the penicillins or the cephalosporins. Because of their excellent absorption fluoroquinolones can be administered not only by intravenous but orally as well.

Cephalosporins

Cephalosporins have a mechanism of action identical to that of the penicillins. However, the basic chemical structure of the penicillins and cephalosporins differs in other respects, resulting in some difference in the spectrum of antibacterial activity. Like the penicillins, cephalosporins have a beta-lactam ring structure that interferes with synthesis of the bacterial cell wall and so are bactericidal. Cephalosporins are derived from cephalosporin C which is produced from Cephalosporium acremonium.

Penicillins

The penicillins are the oldest class of antibiotics. Penicillins have a common chemical structure which they share with the cephalosporins. Penicillins are generally bactericidal, inhibiting formation of the cell wall. Penicillins are used to treat skin infections, dental infections, ear infections, respiratory tract infections, urinary tract infections, gonorrhea.

There are four types of penicillins:

Antibiotic resistance

Antibiotics are extremely important in medicine, but unfortunately bacteria are capable of developing resistance to them. Antibiotic-resistant bacteria are germs that are not killed by commonly used antibiotics. When bacteria are exposed to the same antibiotics over and over, the bacteria can change and are no longer affected by the drug.

Antibiotic Resistance Mechanisms

Bacteria develop ability to hydrolyze these drugs using β lactamase confers resistance to penicillin e.g. E. coli, Staph epidermidis, Pseudomonas aeruginosa, Klebsiella pneumoniae add β lactamase inhibitor e.g. clavulanic acid in amoxicillin-clavulanate (Augmentin) Genetic mutation of mecA

Bacteria Overview

Gram Postive Cocci
Staphylococcus	Staph. aureus MSSA MRSA Staph. epidermis Staph saprophyticus
Streptococcus	Strep pneumoniae Strep pyogenes (Group A) Strep agalacticae (Group B) Strep viridans Strep Bovis (Group D)
Enterococci	E. faecalis (Group D strep)
Gram Positive Bacilli

Antibiotic Classification & Indications

Inhibits Cell Wall Synthesis Penicillins (bactericidal: blocks cross linking via competitive inhibition of the transpeptidase enzyme) Class/Mechanism Drugs Indications (**Drug of Choice) Toxicity Penicillin Penicillin G Aqueous penicillin G Procaine penicillin G Benzathine penicillin G Penicillin V Strep. pyogenes (Grp.A)** Step. agalactiae (Grp.B)** C. perfringens(Bacilli)** Hypersensitivity reaction Hemolytic anemia Aminopenicillins Ampicillin Amoxicillin Above + ↑ Gram-negative: E. faecalis** E. Coli**  Above Penicillinase-resistant-penicillins Methicillin Nafcillin Oxacillin Cloxacillin Dicloxacillin Above + PCNase-producingStaph. aureus Above + Interstitial nephritis Antipseudomonal penicillins Carbenicillin Ticarcillin Piperacillin Above + Pseudomonas aeruginosa**  Above

Antibiotic Grouping By Mechanism

Antibiotic Grouping By Mechanism
Cell Wall Synthesis	Penicillins Cephalosporins Vancomycin Beta-lactamase Inhibitors Carbapenems Aztreonam Polymycin Bacitracin
Protein Synthesis Inhibitors	Inhibit 30s Subunit Aminoglycosides (gentamycin) Tetracyclines Inhibit 50s Subunit Macrolides Chloramphenicol Clindamycin Linezolid Streptogramins
DNA Synthesis Inhibitors	Fluoroquinolones  Metronidazole
RNA synthesis Inhibitors	Rifampin
Mycolic Acid synthesis inhibitors	Isoniazid
Folic Acid synthesis inhibitors	Sulfonamides Trimethoprim

What are Antibiotics?

What are Antibiotics?

The word "antibiotics" comes from the Greek anti ("against") and bios ("life"). The noun “antibiotic” was suggested in 1942 by Dr. Selman A. Waksman, soil microbiologist ⁴.

An antibiotic is a drug that kills or slows the growth of bacteria. Antibiotics are one class of antimicrobials, a larger group which also includes anti-viral, anti-fungal, and anti-parasitic drugs. Antibiotics are chemicals produced by or derived from microorganisms (i.e. bugs or germs such as bacteria and fungi). The first antibiotic was discovered by Alexander Fleming in 1928 in a significant breakthrough for medical science. Antibiotics are among the most frequently prescribed medications in modern medicine.

Antibiotics are used to treat many different bacterial infections.

Types of calcium oxalate

Calcium oxalate is great importance in identification and differentiation of different plants, react between calcium absorbed from soil and oxalate is the result of metabolism          ca.oxalate.

 Calcium oxalate precipitates in cell in different shapes & sizes: