Mycoplasma pneumoniae infections pneumonia

Many microorganisms minimize the effects of the host s defence system against them by mimicking the antigenic stmcture of the host tissne. The eventual immunological response of the host to infection then leads to the autoimmune destmction of itself. Thus, infections with Mycoplasma pneumoniae can lead to production of antibody against normal Group 0 erythrocytes with concomitant haemolytic anaemia. 

Streptococcus pneumoniae remains the commonest cause of pneumonia and responds well to penicillin. In addition, a number of atypical infections may cause pneumonia and include Mycoplasma pneumoniae, Legionella pneumophila, psittacosis and occasionally Q fever. With psittacosis there may be a history of contact with parrots or budgerigars while Legionnaires disease has often been acquired during hotel holidays... 

Broad intravenous antibiotic coverage for the encapsulated organisms can include ceftriaxone or cefotaxime. For patients with true cephalosporin allergy, clindamycin may be used. If staphylococcal infection is suspected owing to previous history or the patient appears acutely ill, vancomycin should be initiated. Macrolide antibiotics, such as erythromycin and azithromycin, may be initiated if Mycoplasma pneumonia is suspected. While the patient is receiving broad-spectrum antibiotics, their regular use of penicillin for prophylaxis can be suspended. Fever should be controlled with acetaminophen or ibuprofen. Because of the risk of dehydration during infection with fever, increased fluid may be needed.6,27... 

The major precipitants of exacerbations of COPD are acute airways infections. The role of bacteria in precipitating exacerbations is controversial. Bacteria may have a primary role in the development of an exacerbation or represent a secondary superinfection of an initial viral process. The major bacterial organisms that have been associated with exacerbations are Haemophilus influenzae. Streptococcus pneumoniae, and Moraxella (Branhamella) catarrhalis. Mycoplasma pneumoniae and Chlamydia pneumoniae may play a part. In COPD patients with a FEVi < 35% predicted gram-negative bacteria, especially Enterobacteriaceae and Pseudomonas spp. play an important part in acute exacerbations. 

Although erythromycin is a well-established antibiotic, there are relatively few primary indications for its use. These indications include the treatment of Mycoplasma pneumoniae infections, eradication of Corynebacterium diphtheriae from pharyngeal carriers, the early preparox-ysmal stage of pertussis, chlamydial infections, and more recently, the treatment of Legionnaires disease, Campylobacter enteritis, and chlamydial conjunctivitis, and the prevention of secondary pneumonia in neonates. 

Respiratory tract infection Bronchitis, pneumonia and other lower respiratory tract infections due to susceptible strains of Strep, pneumoniae, H. influenzae, K. pneumoniae and other organisms including Mycoplasma pneumoniae. Upper respiratory tract infections including sinusitis, otitis, mastoiditis. 

A combination of trimethoprim-sulfamethoxazole is effective treatment for a wide variety of infections including P jiroveci pneumonia, shigellosis, systemic salmonella infections, urinary tract infections, prostatitis, and some nontuberculous mycobacterial infections. It is active against most Staphylococcus aureus strains, both methicillin-susceptible and methicillin-resistant, and against respiratory tract pathogens such as the pneumococcus, Haemophilus sp, Moraxella catarrhalis, and Klebsiella pneumoniae (but not Mycoplasma pneumoniae). However, the increasing prevalence of strains of E coli (up to 30% or more) and pneumococci that are resistant to trimethoprim-sulfamethoxazole must be considered before using this combination for empirical therapy of upper urinary tract infections or pneumonia. 

Bebear CM, Pereyre S. Mechanisms of drug resistance in Mycoplasma pneumoniae. Curr Drug Targets Infect Disord. 2005 5 263-271. 

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). 

Due to its powerful specific activity against commonly isolated community-acquired respiratory tract pathogens [33,149-158], including penicillin-sensitive and -resistant Streptococcus pneumoniae, methicillin-sensitive Staphylococcus aureus, Haemophilus spp., Moraxella catarrhalis and atypical pathogens such as Mycoplasma pneumoniae, Chlamydia pneumoniae and Legionella pneumophila and Klebsiella pneumoniae and anaerobic bacteria [159-162], moxifloxacin was developed as a respiratory tract anti-infective [163-168]. 

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. 

Clarithromycin is indicated for the treatment of mild to moderate upper and lower respiratory tract infections as well as skin infections caused by susceptible strains of Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, H. influenzae, Legionella pneumophila, and Mycoplasma pneumoniae. The usual dosage is 250 to 500 mg twice a day for 7 to 14 days. 

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. 

Ang CW, Tio-Gillen AP, Groen J, Herbrink P, Jacobs BC, van Kon-ingsveld R, Osterhaus ADME, van der Meche FGA, Van Doom PA (2002) Cross-reactive anti-galactocerebroside antibodies and Mycoplasma pneumoniae infections in Guillain-BaiTe syndrome. J Neuroimmunol 130 179—183. 

Griillich, C., Baumert, T.F., Blum, H.E. Acute Mycoplasma pneumoniae infection presenting as cholestatic hepatitis. J. Clin. Microbiol. 2003 41 514-515... 

A 38-year-old woman took norfloxacin (300 mg/day) and tiaramide hydrochloride (300 mg tds) for an infection with Mycoplasma pneumoniae. One day after the start of treatment, her symptoms of cough and fever worsened and she developed lumbago and hematuria. The diagnosis was confirmed by percutaneous renal biopsy. She slowly improved without specific treatment. Lymphocyte stimulation tests were negative, but rechallenge with norfloxacin was followed by bilateral lumbago. 

Maaolides are appropriate antibiotics for the management of respiratory tract infections because they are active against Streptococcus pneumoniae. Streptococcus pyogenes (group A streptococci), and atypical organisms such as Legionella pneumophila. Mycoplasma pneumoniae, and Chlamydia pneumoniae. The newer generation macrolides such as clar-... 

The macrolide antibiotics include erythromycin, clarithromycin, azithromycin, tylosin, tilmicosin and tiamulin. Clindamycin and lincomycin are related lincosamides. Susceptible bacteria include staphylococci, streptococci, Campylobacter jejunii, Clostridium spp., R. equi, Mycoplasma pneumoniae and Chlamydia spp. Drugs in this group are only effective against a few Gram-negative bacteria in cattle, namely some strains of Pasteurella and Haemophilus spp. Macrolides and lincosamides are associated with causing colitis in horses, so their use is usually restricted to p.o. erythromycin for the treatment of R. equi infections in foals. Subantimicrobial doses of erythromycin are administered i.v. to horses for gastrointestinal prokinetic action. 

The answer is a. (Murray, pp 452-467. Scriver, pp 3-45. Sack, pp 1-40. Wilson, pp 101—120.) Virulent strains of bacteria that cause severe, life-threatening respiratory tract infections can often be successfully treated with erythromycin. These include Mycoplasma pneumoniae, various Legionella species, and Bordetella pertussis. The mechanism of action of erythromycin is to specifically bind the 50S subunit of bacterial ribosomes. Under normal conditions, after mRNA attaches to the initiation site of the 30S subunit, the 50S subunit binds to the 30S complex and forms the 70S complex that allows protein chain elongation to go forward. Elongation is prevented in the presence of erythromycin. 

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