Mycoplasm pneumoniae

The most serious pulmonary disease of cattle is contagious bovine pleuropneumonia (or mycoplasmal pneumonia). It is caused by Mycoplasma mycoides, a bacteria-like microorganism, —0.01 fjim in diameter (cf. bacterial diameter, —1 p,m). It has no rigid cell wall. The disease has been eliminated from Europe and USA for many years, but is still prevalent in South America, Australia, Asia and Africa. Mortality can be as high as 70% amongst untreated animals. 

Tetracycline has been administered to subjects exposed to mycoplasmal pneumonia, but the effectiveness of such treatment has not been documented. The answer is (A). 

Erythromycin has much the same spectrum of antibacterial activity as penicillin. Because erythromycin-resistant strains of the commoner bacteria abound, the use of this antibiotic is becoming confined to three diseases mycoplasmal pneumonia, diphtheria, and Legionnaires disease. 

Differential Diagnosis Q fever usually presents as an undifferentiated febrile illness, or a primary atypical pneumonia, which must be differentiated from pneumonia caused by mycoplasm, Tegionnaires disease, psittacosis or Chlamydia pneumoniae. More rapidly progressive forms of pneumonia may look like bacterial pneumonia including tularemia or plague. 

Fig. 8. Principal component analysis of the distribution of the predicted folds in bacterial, archaeal, and eukaryotic proteomes. (a) First and second principal components (b) third and fourth principal components. Aae, Aquifex aeolicus Mge, Mycoplasm genitalium Mpn, Mycoplasma pneumoniae Rpr, Rickettsia prowazekii Bbu, Borrelia burgdorferi Bsu, Bacillus subtilis, Hin, Haemophilus influenzae, Hpy, Helicobacter pylori Tma, Thermotoga mari-...

Deaths in rats resulting from single-exposure concentration/duration combinations expected to produce 50%-90% mortality usually occurred within 24 hours. These deaths were attributed to cardiac or respiratory failure and were probably a direct effect of 1,2-dibromoethane toxicity. Deaths resulting from exposure concentration/duration combinations expected to produce 0.01%-50% mortality occurred as long as 12 days after exposure and were due to pneumonia. The authors attributed pneumonia to 1,2-dibromoethane-induced lung injury, but this lesion could also have been due to intercurrent bacterial or mycoplasmal pulmonary infection. Rats free of enzootic respiratory infections were not available in 1952. More contemporary inhalation studies of 1,2-dibromoethane using commercially produced rats (Nitschke et al. 1981 NTP 1982) did not report pneumonic lesions or pneumonia-related mortality. 

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