Macrolides(Erythromycin ) 【Antibacterial activity 】 Erythromycin is bacteriostatic It is effective against gram-positive organisms It is active against some gram-negative organisms Mycoplasma, Chlamydiae, Legionella are susceptible

Vancomycins 【Antibacterial activity 】 It is bactericidal agent It is primarily active against gram-positive bacteria (MRSA),but enterococci are resistant 3. Gram-negative bacilli are resistant to vancomycin

Aminoglycosides

【Mechanism of action】 interfere with the initiation complex Decoding P A interfere with the initiation complex nonfunctional or toxic protein synthesis aminoglycosides(30S,A) breakup of polysomes into nonfunctional monosomes P A P A

Tetracyclines and Chloramphenicol Section 1 Tetracyclines

【Adverse effect 】 Gastric discomfort: Nausea, vomiting, and diarrhea Bony structures and Teeth :discoloration and hypoplasia of the teeth and a temporary stunting of growth Fatal hepatotoxicity: in pregnant women Phototoxicity: severe sunburn

4. Vestibular problems: dizziness, nausea, vomiting 5. Pseudotumor cerebri: Benign intracranial hypertension , headache , blurred vision 6. Superinfections: pseudomembranous enterocolitis Vancomycin:

Section 2 Chloramphenicol 【 Antibacterial action】 Chloramphenicol is either bacteriostatic or bactericidal It is active against both aerobic and anaerobic gram-positive and gram-negative organisms It has effective against rickettsiae, helicoids, Chlamydia and mycoplasma.

【Mechanism of action】 Chloramphenicol(50S,A) Peptidyl transferase P A

【pharmacokinetics】 Chloramphenicol may be administered either intravenously or orally It penetrate blood-brain barrier, placental barrier, blood-ocular barrier It is inactivated by conjugation with glucuronic acid in liver, secreted by the renal tubule

【Clinical uses】 Bacterial meningitis: meningococcal meningitis Rickettsial infections: typhus or Rocky Mountain spotted fever Eye infection: outer eye infection, intraocular infection, eyeball infection Anaerobic infection: peritoneal abscess, pelvic inflammation and peritonitis

【Adverse effect】 Bone marrow depression Aplastic anemia Gray baby syndrome: poor feeding, depressed breathing, cardiovascular collapse, cyanosis and death

【Drug resistance 】 Produce inactivator： acetyl coenzyme A transferase Membrane permeability is decreased, chloramphenicol penetrate the organism less

Artificial Synthetic antibacterial drugs Section I Quinolones

The second generation: The third generation: The fourth generation: The first generation : nalidixic acid, pipemidic acid The second generation: norfloxacin, ofloxacin, ciprofloxacin The third generation: sparfloxacin, levofloxacin, grepafloxacin The fourth generation: clinafloxacin, gatifloxacin.

Fluorequionlones: The second generation The third generation The fourth generation

【antibacterial action】 All of the quinolones are bactericidal First generation only has active against some gram-negative bacteria Second generation expend gram-negative bacteria spectrum Third generation have active against gram-positive organisms, chlamydia, mycoplasma, Legionella and Bacillus tuberculosis The fourth generation have active against anaerobic bacterium

Inhibit the replication of bacterial DNA 【Mechanism of action】 Inhibit the replication of bacterial DNA interfering with the action of DNA gyrase: gram-negative bacteria interfering with the action of topoisomerase IV: gram-positive bacteria

【Clinical uses】 1. Genitourinary tract infections : Urinary tract infections, prostatitis, cervicitis 2. Intestinal infection: gastroenteritis, bacillary dysentery, diarrhea 3. Respiratory infection: bronchitis, nasosinusitis ,pneumonia 4. Skeletal system infection: medullitis and arthrosis

【adverse effect】 Gastrointestinal discomfort: poor appetite, nausea, vomiting, diarrhea 2. CNS problems: dizziness, headache, insomnia, convulsion 3. Allergies： angioneurotic edema，skin rash Contraindications: pregnancy, nursing mothers and children

【drug resistance 】 1. Altered target: modifications in the bacterial DNA gyrase 2. Decreased accumulation: decreased number of porin proteins increased energy-dependent efflux system

norfloxacin This agent is effective against both gram-negative and gram-positive organisms in treating urinary tract infections and prostatitis, but not in systemic infections

ciprofloxacin Ciprofloxacin is the most potent, used to treat many systemic infections with the exception of serious infections caused by MRSA, the enterococci and pneumococci. It is particularly useful in treating infections caused by gram-negative bacilli.

Ofloxacin Ofloxacin is primarily used in the treatment of prostatitis. It may be used as alternative therapy in patients with gonorrhea. It has some benefit in the treatment of skin and lower respiratory tract infections.

Section II Sulfonamides classification oral, absorbable oral, nonabsorbable topical

【Antibacterial action】 The sulfonamides are bacteriostatic; These drugs inhibit both gram-positive and gram negative bacteria; They have active against nocardia, Chlamydia trachomatis, and some protozoa; They have no effective against mycoplasma, Rickett's organism, helicoid

【Mechanism of action】 PABA + Pteridine Sulfonamides Dihydropteroate synthase Sulfonamides Dihydropteroic acid Glutamate Dihydrofolate Dihydrofolate reductase(DHFR) Tetrahydrofolate Purine、 pyrimidine nucleotide precursor

【Clinical uses 】 Systemic infections: oral and absorbable sulfonamides 2. Intestinal infection: oral and nonabsorbable sulfonamides 3. Wound infection: topical sulfonamides

【adverse effect 】 1. Crystalluria: crystallura, hematuria, obstruction adequate hydration and alkalinization of urine 2. Kernicterus: sulfonamides displace bilirubin from binding sites on serum albumin 3. Hypersensitivity: rashes, angioedema 4. Hemopoietic disturbances: Hemolytic anemia, Granulocytopenia thrombocytopenia

Contraindications: newborns and infants less than 2 months old as well as pregnant women

【drug resistance 】 Increased PABA synthesis: overcome the inhibition of the dihydropteroate synthetase by the sulfas 2. Altered enzyme: decreased affinity for the sulfonamides 3. Decreased uptake: decreased permeability of membrane

Oral, absorbable agents Sulfisoxazole Sulfamethoxazole Sulfadiazine

Sulfisoxazole and sulfamethoxazole are used almost exclusively to treat urinary tract infections. Sulfadiazine achieves high concentrations in cerebrospinal fluid, therefore it has preventative and therapeutic effective against Epidemic meningitis

Oral nonabsorbable agents Sulfasalazine is widely used in ulcerative colitis, enteritis, and other inflammatory bowel disease.

Topical Agents Sodium sulfacetamide Mafenide acetate

Sodium sulfacetamide ophthalmic solution or ointment is effective treatment for bacterial conjunctivitis and as adjunctive therapy for trachoma. Mafenide acetate is used topically to prevent bacterial colonization and infection of burn wounds.

Trimethoprim 1. The antibacterial spectrum is similar to that of sulfamethoxazole It inhibited dihydrofolate reductase It is used alone in acute urinary tract infections and in the treatment of bacterial prostatitis It induce megaloblastic anemia, leukopenia, and granulocytopenia It altered dihydrofolate reductase, resulting in drug resistance

Co-trimoxazole Co-trimoxazole is combination of trimethoprim- sulfamethoxazole It shows greater antimicrobial activity than equivalent quantities of either drug used alone It inhibits two sequential steps in the synthesis of tetrahydrofolic acid

pyrimidine nucleotide precursor PABA + Pteridine Dihydropteroate synthase sulfamethoxazole Dihydropteroic acid Glutamate Dihydrofolate Trimethoprim (TMP) Dihydrofolate reductase(DHFR) Tetrahydrofolate Purine、 pyrimidine nucleotide precursor

4. Co-trimoxazole is used to treat upper respiratory infection, urinary tract infection， intestinal infection，typhoid fever 5. It is less frequently encountered than resistance to either of the drugs alone