Antibiotic and Chemotherapeutic agents

Microbiology

1. Antibiotics and other Chemotherapeutic Agents by, Miss Areesha Ahmad Lecturer Microbiology B.Sc (H), M.Sc , M.Phil and Ph.D scholar (Microbiology)

2. Chemotherapy and chemotherapeutic agent The treatment of a disease with a chemical substance is known as chemotherapy. The chemical substance is called a chemotherapeutic agent.

3. Antifungal Antibiotics Nystatin Restricted to yeast and other fungi e.g., Candida, Aspergillus, and Penicillium Fungicidal in action It is polyene antibiotic and its structure, chemistry, mechanism of action and resistance resemble those of Amphotericin B.

4. Griseofulvin Source = Penicillium griseofulvin Treatment of many superficial fungal infection of skin and body surfaces Also effective in the treatment of some systemic mycoses. Drug is administrated orally.

5. Antiviral Chemotherapeutic Agents

6. Acycloguanosine Nucleoside Analog Active against herpes virus in animals Inhibition of Nucleic acid synthesis Prevent the incorporation of thymidine into DNA.

7. A mantadine Effective against influenza A virus Not effective against influenza B virus Interefere with uncoating of virus particles and release of their nucleic acids.

8. Antitumor Antibiotics A type of  antitumor  drug that blocks cell growth by interfering with DNA, the genetic material in cells.  These  medications interfere with DNA replication and often damage the DNA itself, leading to cell death . Antitumor agents  prevent or inhibit the formation or growth of tumors and are known as  antitumor ,  anticancer , chemotherapeutic, or antimetastatic   agents .  Antitumor agents  kill those cells that divide rapidly, which is one of the main property in most types of cancer cells. Antitumor activity e.g., Anthramycin group ( anthramycin , sibromycin , tomaymycin , and neothramycin ) Need high level of specificity

9. Development of Resistance to antibiotics Antibiotic resistance  happens when germs like bacteria and fungi  develop  the ability to defeat the drugs designed to kill them. That means the germs are not killed and continue to grow. Infections caused by  antibiotic - resistant  germs are difficult, and sometimes impossible, to treat . Examples  of bacteria that are  resistant  to  antibiotics  include methicillin- resistant  Staphylococcus aureus (MRSA), penicillin- resistant  Enterococcus, and multidrug- resistant  Mycobacterium tuberculosis (MDR-TB), which is  resistant  to two tuberculosis drugs, isoniazid and rifampicin.

10. Mechanism of antibiotic resistance Competitive inhibition between an essential metabolite and a metabolite analog. Development of an alternative metabolic pathway which bypasses some reaction that would normally be inhibited by drug. Production of an enzyme eg ., penicillinase for penicillin Synthesis of an excess enzyme over the amount that can be inactivated by the antibiotic or drug. Inability of drug to penetrate the cell due to some alteration of cell membrane. Alteration of ribosomal protein structure.

11. Transmission of D rug Resistance

12. Microbial susceptibility to chemotherapeutic agent

13. Thankyou...