
Full text loading...
Category: Clinical Microbiology; Environmental Microbiology
Antimicrobial Resistance in Mycoplasma spp., Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555819804/9781555819798_Chap20-1.gif /docserver/preview/fulltext/10.1128/9781555819804/9781555819798_Chap20-2.gifAbstract:
Mycoplasmas belong to the phylum Firmicutes (Gram-positive bacteria with low G+C content), to the class Mollicutes (from Latin: mollis, soft; cutis, skin), to the order Mycoplasmatales, and to the family Mycoplasmataceae. They presumably evolved by degenerative evolution from Gram-positive bacteria and are phylogenetically most closely related to some clostridia. Mycoplasmas are the smallest self-replicating prokaryotes (diameter of approximately 0.2 to 0.3 μm) with the smallest genomes (500 to 1,000 genes). They are characterized by the lack of a cell wall. The mycoplasma cell contains the minimum set of organelles essential for growth and replication: a plasma membrane, ribosomes, and a genome consisting of a double-stranded circular DNA molecule ( 1 ). The mycoplasma genome is characterized by a low G+C content and by the use of the universal stop codon UGA as a tryptophan codon. As a result of their limited genetic information, mycoplasmas express a small number of cell proteins and lack many enzymatic activities and metabolic pathways ( 1 ). Their nutritional requirements are therefore complex, and they are dependent on their host for many nutrients. This phenomenon explains the great difficulty of in vitro cultivation of mycoplasmas, with complex media containing serum (as a source of fatty acids and cholesterol) and a metabolizable carbohydrate (as a source of energy, for example, glucose, arginine, or urea).
Full text loading...
Main pathogenic Mycoplasma species in humans and livestock animals a
Examples of methods used (culture media, methods and measurement, expression of results) for the determination of antimicrobial activities toward animal mycoplasmas a
MIC values (range in μg/ml) for various antimicrobials against avian Mycoplasma species (M. gallisepticum and M. synoviae)
MIC values (range in μg/ml) for various antimicrobials against swine Mycoplasma species (M. hyopneumoniae, M. hyorhinis, and M. hyosynoviae)
MIC values (range in μg/ml) for various antimicrobials against ruminant Mycoplasma species (M. bovis and M. agalactiae)
Mutations in the 23S rRNA genes and in the ribosomal proteins L4 and L22 conferring resistance in animal Mycoplasma species
Mutations in DNA-gyrase (GyrA and GyrB) and topoisomerase IV (ParC and ParE) associated with fluoroquinolone resistance in animal Mycoplasma species