Tetracycline mycoplasma infections

The answer is b. (Hardman, p 1128.) Tetracycline is one of the drugs of choice in the treatment of Rickettsia, Mycoplasma, and Chlamydia infections. The antibiotics that act by inhibiting cell-wall synthesis have no effect on Mycoplasma because the organism does not possess a cell wall penicillin G, vancomycin, and bacitracin will be ineffective. Gentamicin has little or no antimicrobial activity with these organisms. 

Tetracycline Prevents bacterial protein synthesis by binding to the 30S ribosomal subunit Bacteriostatic activity against susceptible bacteria Infections caused by mycoplasma, chlamydiae, rickettsiae, some spirochetes malaria H pylori acne Oral mixed clearance (half-life 8 h) dosed every 6 h divalent cations impair oral absorption Toxicity Gastrointestinal upset, hepatotoxicity, photosensitivity, deposition in bone and teeth... 

Tetracyclines, as broad-spectrum antibiotics, are the drugs of choice in treating Mycoplasma pneumoniae infections. Most tetracyclines are absorbed to various degrees (30 to 100%) from the gastrointestinal tract, primarily from the stomach and upper small intestine. The absorption of tetracyclines is hindered by milk and milk products, by numerous antacids such as aluminum hydroxide, sodium bicarbonate, and calcium carbonate, and by iron preparations such as ferrous sulfate. Therefore, these and similar substances should not be administered orally together with tetracycline (Figure 3.4). 

Although the clinical usefulness of tetracyclines is limited for most of the common microbial pathogens, they remain drugs of choice (or very effective alternative therapy) for a wide variety of infections caused by less common pathogens. These include brucellosis rickettsial infections such as Rocky Mountain spotted fever, typhus, and Q fever Mycoplasma pneumonia cholera plague Ureaplasma urethritis Chlamydia infections and Lyme disease. Oral doxycycline, 100 mg orally twice a day for 7 days, is a recommended treatment for chlamydial sexually transmitted disease. 

SJS was for many years considered a severe variant of erythema multiforme major (EMM) however, over the past decade some experts have reclassified SJS as a less severe variant of toxic epidermal necrolysis (TEN) rather than a form of EMM. However, this perspective is not universally accepted. SJS occurs acutely in all ages, with 20% in children and a peak incidence in adults between the second and fourth decades of life. SJS is a potentially fatal disorder with a mortality of approximately 5%.TEN has a mortality rate of approximately 30%. About 50% of cases of these disorders are idiopathic. Identifiable causal factors include microbial infection, particularly with Mycoplasma pneumoniae and HS Vj and medications, including sulfonamides, tetracycline, penicillin, nonsteroidal anti-inflammatory drugs (NSAIDs), psychotropic agents, antiepileptics, and immunizing vaccines. Recent research suggests that HSV infection is a principal fector in the genesis of EMM, whereas medications are a more likely precipitant of SJS and TEN. 

Methacycline is a broad-spectrum tetracycline antibiotic that is synthetically derived from oxytetracycline. Methacycline (600 mg/day) is indicated in infections caused by Gram-positive bacteria, Rickettsia, Mycoplasma, Amoeba, and Chlamydia. It binds to the 308 subunit of the bacterial... 

Tetracyclines, which are bacteriostatic, have the broadest spectrum of activity and are effective against infections with Gram-positive and Gram-negative bacteria Rickettsia, Mycoplasma, amoeba, and Chlamydia. These agents consist of ... 

Primary uses Tetracyclines are drugs of first choice in the treatment of infections caused by Mycoplasma pneumoniae (in adults), chlamydia, rickettsia, and vibrios. 

Tetracycline (Achromycin) Doxycycline (Vibramycin) Demeclocycline (Dedomycin) Minocycline (e.g., Minocin) Inhibits protein synthesis. Binds to 30s subunit blocking amino acid-linked tRNA from binding to the A site of the ribosome. Most Staphylococcus and Streptococcus strains, enterics, mycoplasma, spirochetes, rickettsiae. Not DOC for any microorganism. Used for acne and chlamydial infections in teens. 

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