Antibacterial agents

chemotapeutic agents

Antibacterial agents

Substances that are used to kill or inhibit the growth of bacteria.

Protein synthesis

The process by which cells build proteins using information from DNA.

30s subunit

A component of the ribosome that is involved in protein synthesis.

Tetracyclines

Doxycycline (second generation):A type of antibiotic that belongs to the tetracycline class, specifically doxycycline which is a second-generation tetracycline.

Mechanism of Action

The specific way in which a drug or substance produces its effect in the body.

Spectrum of activity

The range of bacteria or microorganisms that a drug is effective against.

Pharmacokinetics

The study of how a drug is absorbed, distributed, metabolized, and excreted by the body.

Resistance

The ability of bacteria or microorganisms to withstand the effects of a drug and continue to grow or multiply.

Aminoglycosides

Streptomycin:A class of antibiotics that includes streptomycin, which is used to treat bacterial infections.

Bactericidal

A term used to describe drugs or substances that kill bacteria.

Side effects

Unintended or undesirable effects of a drug or substance.

50s subunit

A component of the ribosome that is involved in protein synthesis.

Chloramphenicol

An antibiotic that inhibits protein synthesis by binding to the 50s subunit of the ribosome.

Macrolides

Erythromycin:A class of antibiotics that includes erythromycin, which is used to treat bacterial infections.

Nucleic synthesis

The process of building nucleic acids, such as DNA and RNA.

Actinomycin D

An antibiotic that inhibits nucleic acid synthesis by binding to DNA and preventing transcription.

Metronidazole

An antibiotic that disrupts DNA synthesis in anaerobic bacteria.

Inhibition of DNA gyrase

Fluoroquinolones:A class of antibiotics that inhibit DNA gyrase, an enzyme involved in DNA replication and repair.

Ciprofloxacin

A commonly used antibiotic primarily effective against Gram-negative bacteria, such as chlamydia.

Levofloxacin

An antibiotic used specifically against Streptococcus pneumoniae and can cause side effects such as gastrointestinal issues, CNS effects, allergic reactions, and joint and bone problems.

Antibiotic Resistance

The ability of bacteria to develop defenses against antibiotics, limiting the effectiveness of medical treatments for infections.

Sulphonamides

A group of antibiotics that inhibit the synthesis of folic acid in bacteria, leading to their death. They can cause side effects such as gastrointestinal disturbances and hypersensitivity reactions.

Tyrocidines & Gramicidin

Antibiotics that disorganize the structure of bacterial cell membranes, leading to cell death. They contain the amino acid ornithine, which is not found in human proteins.

Beta-lactams

A class of antibiotics, including penicillin and cephalosporins, that interfere with the synthesis of peptidoglycan, a component of bacterial cell walls. They are bactericidal and can cause side effects such as hypersensitivity reactions and gastrointestinal disturbances.

Antibiotic Resistance Mechanisms

Enzymatic inactivation of the drug, altered drug binding site, decreased drug accumulation, and development of alternative resistance pathways are the main biochemical mechanisms bacteria use to become resistant to antibiotics.

Conjugation

A mechanism of antibiotic resistance transfer between bacteria through direct cell-to-cell contact using pili. It can occur across species barriers.

Transduction

The transfer of antibiotic resistance genes from one bacterium to another of the same species through a bacteriophage.

Transformation

A gene transfer mechanism where bacteria take up "naked DNA" from the environment and incorporate it into their genome. It is less commonly used for sharing antibiotic resistance genes.

Enzymatic Inactivation of the Drug

Bacteria produce enzymes like beta-lactamases and acetyltransferases to inactivate antibiotics such as penicillins, cephalosporins, and chloramphenicol.

Altered Drug Binding Site

Bacteria mutate their drug binding sites to reduce the affinity for antibiotics like aminoglycosides, macrolides, quinolones, and rifampicin.

Decreased Drug Accumulation

Bacteria develop mechanisms like increased efflux and altered permeability to pump out or prevent the entry of antibiotics, leading to resistance against drugs like tetracyclines, erythromycins, fluoroquinolones, and ampicillin.

Development of Alternative Resistance Pathways

Bacteria modify enzymes or pathways targeted by antibiotics, making them unrecognizable or ineffective. Examples include changes in dihydrofolate reductase for trimethoprim resistance.