Mycoplasmas

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Mycoplasmas

The smallest prokaryotic microorganisms that are able to grow on cell-free artificial media. Their genome size is also among the smallest recorded in prokaryotes, about 5 × 108 to 109 daltons. The mycoplasmas differ from almost all other prokaryotes in lacking a rigid cell wall and in their incapability to synthesize peptidoglycan, an essential component of the bacterial cell wall.

Taxonomically, the mycoplasmas are assigned to a distinct class, the Mollicutes, containing two orders, Mycoplasmatales and Acholeplasmatales. The distinction between the orders is based primarily on differences in nutritional criteria: members of the Mycoplasmatales require cholesterol or other sterols for growth whereas those of the second order do not. The term mycoplasmas is generally used as the vernacular or trivial name for all members of the class Mollicutes, irrespective of the classification in a particular genus.

The mycoplasmas are almost ubiquitous in nature. Several species are important pathogens of humans, animals and plants, while others constitute part of the normal microbial flora of, for example, the upper respiratory and lower urogenital tracts of humans. Mycoplasma pneumoniae was found to be the cause of cold agglutinin-associated primary atypical pneumonia. This disease is particularly frequent in the 5–15-year age group; it is probably endemic almost all over the world and often reaches epidemic proportions at intervals of 4 to 5 years.

Mycoplasmas are generally highly resistant to benzyl penicillin and other antibiotics which act by interfering with the biosynthesis of peptidoglycan. They are usually susceptible to antibiotics that specifically inhibit protein synthesis in prokaryotes, such as tetracyclines and chloramphenicol. Susceptibility to other antibiotics, such as erythromycin and other macrolides, is variable. See Antibiotic, Bacterial physiology and metabolism, Plant pathology, Pneumonia

References in periodicals archive ?
Mycoplasma genitalium (MG) was detected by Anyplex II STI-7 in 2/110 (1.81%), one of which was also detected by MWD-ONE as Mycoplasma species because the latter assay cannot discriminate between MG and Mycoplasma species.
The US FDA's marketing authorisation of the Aptima Mycoplasma genitalium Assay was awarded to Hologic Inc.
ovipneumoniae and illustrates the divergence from the other Mycoplasma spp.
The swabs were cultured in pleuropneumonia-like organisms (PPLO) broth media at 37[degrees]C for 24 h., and then inoculated in PPLO media agar plate at 37[degrees]C for 1 week to examine the presence of Mycoplasma colonies (Evans et al., 2009).
MM cluster specific PCR showed 49 (16.3%) samples were found positive, of which 34 (11.3%) were found positive for Mycoplasma mycoides subsp.
Comparison of culture and PCR to detect Mycoplasma agalactiae and Mycoplasma mycoides sub sp.
There was no doubt the decision to attempt to eradicate Mycoplasma bovis from New Zealand was going to cause pain and anguish for more farmers, Federated Farmers president Katie Milne said.
Next, PCR assays were carried outusing specific primers for Ma (FS1:5'-AAAGGTGCTTGAGAAATGCC-3' and FS2: 5'-GTTGCAGAAGAAAGTCCAATCA-3', which amplify a 375-bp fragment) and for the Mycoplasma mycoides cluster (F-REAP:5'-GAAACGAAAGATAATACCGCATGTAG-3'and R-REAP:5'-CCACTTGTGCGGGTCCCCGTC-3', which amplify a 785-bp fragment).
In recent years, researchers worldwide have identified Mycoplasma pneumoniae as one of the most common pathogens causing adult community-acquired pneumonia (CAP).