Explain the use of and the mode of action for the antibiotic, Tetracycline?
name 5 antibiotics аnd thеіr uses. οf thе 5 antibiotics, ехрlаіn thеіr mode οf action. Antibiotics аrе: Tetracycline, Streptomycin, Polymyxin B, Pencillin аnd Cephalosporin
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well,here is a useful brief answer:
A-Tetracycline:
# mode of action:
1.Bacteriostatic.
2.Prevents bonding of tRNA to mRNA on ribosome.
# uses:
1.Treats intestinal amebiasis.
2.Effective against Rickettsia and Chlamydia.
3.Against syphilis and gonorrhea.
B-Streptomycin:
# mode of action:
1.Bacteriostatic
2.Inhibits peptide bond formation.
# uses:
1.Tuberculosis.
2.Used for tularemia,plague.
2.Urinary tract infections.
3.Enteric infections.
4.Nosocomial infections.
5.Against penicillin-resistant gonorrhea
C-Polymyxin B:
# mode of action:
1.Bacteriocidal
2.Causes disorientation of lipoprotein constituents resulting in a distortion.
# uses:
1.Against Pseudomonal infection.
2.Against Gram -ve in wounds,abrasions,and burns.
3.Against E.Coli infection.
D-Pencillin:
# mode of action:work by inhibiting the formation of peptidoglycan cross links in the bacterial cell wall.
# uses:
1.STD:like syphilis & gonorrhea.
2.Cardiac infection:Bacterial Endocarditis.
3.Brain infectins:Meningitis,Encephalitis.
4.Respiratory infections:Pneumonia,Lung abscess.
5.Miscellanous:Tonsilitis,Pharyngitis.
6.Skin infections.
7.Prophylasis:Rheumatic Fever .
8.Septicemia in children.
E-Cephalosporins:
# mode of action:work by inhibiting the formation of peptidoglycan cross links in the bacterial cell wall.
# uses:
1.Against Staphylococcal & Streptococcal infections.
2.Against Escherichia coli,Klebsiella pneumoniae and Proteus mirabilis.
3.Hospital-acquired infections.
The tetracyclines are broad-spectrum antibiotics whose value has decreased owing to increasing bacterial resistance. They remain, however, the treatment of choice for infections caused by chlamydia (trachoma, psittacosis, salpingitis, urethritis, and lymphogranuloma venereum), rickettsia (including Q-fever), brucella (doxycycline with either streptomycin or rifampicin), and the spirochaete, Borrelia burgdorferi (Lyme disease). They are also used in respiratory and genital mycoplasma infections, in acne, in destructive (refractory) periodontal disease, in exacerbations of chronic bronchitis (because of their activity against Haemophilus influenzae), and for leptospirosis in penicillin hypersensitivity (as an alternative to erythromycin).
Microbiologically, there is little to choose between the various tetracyclines, the only exception being minocycline which has a broader spectrum; it is active against Neisseria meningitidis and has been used for meningococcal prophylaxis but is no longer recommended because of side-effects including dizziness and vertigo (see section 5.1, table 2 for current recommendations). Deteclo® (a combination of tetracycline, chlortetracycline and demeclocycline) does not have any advantages over preparations containing a single tetracycline.
Oral infections
In adults, tetracyclines can be effective against oral anaerobes but the development of resistance (especially by oral streptococci) has reduced their usefulness for the treatment of acute oral infections; they may still have a role in the treatment of destructive (refractory) forms of periodontal disease. Doxycycline has a longer duration of action than tetracycline or oxytetracycline and need only be given once daily; it is reported to be more active against anaerobes than some other tetracyclines.
For the use of doxycycline in the treatment of recurrent aphthous ulceration, oral herpes, or as an adjunct to gingival scaling and root planing for periodontitis.
Cautions
Tetracyclines should be used with caution in patients with hepatic impairment (Appendix 2) or those receiving potentially hepatotoxic drugs. Tetracyclines may increase muscle weakness in patients with myasthenia gravis, and exacerbate systemic lupus erythematosus. Antacids, and aluminium, calcium, iron, magnesium and zinc salts decrease the absorption of tetracyclines; milk also reduces the absorption of demeclocycline, oxytetracycline, and tetracycline. Other interactions: Appendix 1 (tetracyclines).
Contra-indications
Deposition of tetracyclines in growing bone and teeth (by binding to calcium) causes staining and occasionally dental hypoplasia, and they should not be given to children under 12 years, or to pregnant (Appendixes 4) or breast-feeding women (Appendix 5). However, doxycycline may be used in children for treatment and post-exposure prophylaxis of anthrax when an alternative antibacterial cannot be given [unlicensed indication]. With the exception of doxycycline and minocycline, the tetracyclines may exacerbate renal failure and should not be given to patients with kidney disease.
Side-effects
Side-effects of the tetracyclines include nausea, vomiting, diarrhoea (antibiotic-associated colitis reported occasionally), dysphagia, and oesophageal irritation. Other rare side-effects include hepatotoxicity, pancreatitis, blood disorders, photosensitivity (particularly with demeclocycline), and hypersensitivity reactions (including rash, exfoliative dermatitis, Stevens-Johnson syndrome, urticaria, angioedema, anaphylaxis, pericarditis). Headache and visual disturbances may indicate benign intracranial hypertension (discontinue treatment); bulging fontanelles have been reported in infants.
Captaincook missed 80% of your question! Tetracycline works by inhibiting protein synthesis. Streptomycin works in a similar way. I don’t know the mechanism for polymyxin but both penicillin all cephalosporins inhibit bacterial cell wall synthesis by binding to something in the bacterial cell wall called "penicillin binding protein".
Tetracyclines are used most commonly for rare rickettsial infections and acne. They are used for little else because of resistance and photosensitivity. Streptomycin is used pretty much only for tuberculosis. Polymyxin B is used topically (on the skin), it is one of the ingredients in Neosporin. It can also be used in combination with other antibiotics as antibiotic ear and eye drops. Penicillin is not used much at all any more except for cases of syphillis and when a brave person is trying to treat strep throat (brave because the patient probably won’t take it). Cephalosporins are used for lots of things, pneumonias, abdominal infections, urinary tract infections, meningitis, skin infections, etc. They things they are not used for is pneumonia caused by a select few organisms (chlamydia, mycoplasma, etc.), tuberculosis, and a few others.