Antibiotics are substances produced by microorganisms effective in killing or inhibiting the growth of other microorganisms
Antiprotozoal Agents
Drugs used to treat protozoal diseases
First-generationcephalosporins are active primarily against Gram-positive bacteria
Natural penicillins are produced and can be purified directly from cultures of Penicillium moulds
Antifungal Agents
Used to treat fungal diseases
Antimicrobial Agents
Chemotherapeutic agents used to treat infectious diseases
Any chemical (drug) used to treat an infectious disease
Either by inhibiting or by killing pathogens in vivo
Antimicrobial agents are antibiotics
Chemotherapy
Use of any chemical (drug) to treat any disease or condition
Antiviral Agents
Used to treat viral diseases
All antibiotics are antimicrobial agents, but not all antimicrobial agents are antibiotics
Semisynthetic antibiotics are chemically modified to kill a wider variety of pathogens or reduce side effects
Major categories of antibacterial agents
Penicillins
Cephalosporins
Penicillins interfere with the synthesis of bacterial cell walls and have a maximum effect on actively dividing bacteria, making them bactericidal drugs
Second-generation cephalosporins have increased...
Third-generationcephalosporins
Greater activity against Gram negatives, including Pseudomonas aeruginosa
First-generationcephalosporins
Active primarily against Gram-positive bacteria
Tetracyclines
Broad-spectrum drugs
Target bacterial ribosomes
Bacteriostatic
Effective against a wide variety of bacteria
Aminoglycosides
Bactericidal broad-spectrum drugs
Inhibit bacterial protein synthesis
Toxicity limits their use
Effective against a wide variety of bacteria
Fifth-generationcephalosporins
Expanded activity against aerobic Gram-positive cocci, including MRSA and MRSE
Macrolides
Inhibit protein synthesis
Bacteriostatic at lower doses and bactericidal at higher doses
Effective against chlamydias, mycoplasmas, T. pallidum, Legionella spp.
Fluoroquinolones
Bactericidal drugs
Inhibit DNA synthesis
Effective against Enterobacteriaceae and P. aeruginosa
Antibioticsproducedbymoulds
Penicillin
Glycopeptides
Target the cell envelope
Excellent activity against most aerobic and anaerobic Gram-positive bacteria
Enterococci becoming resistant to these drugs
Have toxic side effects
Carbapenems
Powerful antibacterial
Target the cell envelope
Excellent activity against a broad spectrum of bacteria
Synergism involves using two antimicrobial agents together to produce a greater degree of pathogen killing than achieved by either drug alone
Antifungal agents are more difficult to use than antimicrobial drugs
Sulfonamide
Inhibit production of folic acid in bacteria
Bacteriostatic
Called competitive inhibitors
Effective against bacteria requiring PABA to synthesize folic acid
Fourth-generation cephalosporins
Active against both Gram positives and Gram negatives, including P. Aeruginosa
Second-generationcephalosporins
Increased activity against Gram-negative bacteria
Sulfonamide
Sulfamethoxazole + Trimethoprim
Macrolides
Erythromycin, Clarithromycin, Azithromycin
Tetracyclines
Doxycycline, Tetracyclines
Penicillin
Interfere with cell wall synthesis
Bactericidal
Classified as first, second, third, fourth, and fifth-generation cephalosporins
Carbapenems
Imipenem, Meropenem
Antimicrobialagents in therapy may require multidrug therapy to destroy all pathogens and prevent resistant mutant pathogens from emerging