Mycoplasma pneumoniae: Susceptibility and Resistance to Antibiotics

Cécile Bébéar; Sabine Pereyre; Olivia Peuchant


Future Microbiol. 2011;6(4):423-431. 

In This Article

Intrinsic Resistance

Two types of intrinsic resistance are found in mycoplasmas, the first common to all species in the class Mollicutes and the other specific to certain species. These properties have been used to isolate mycoplasmas from specimens contaminated by other bacteria, and to differentiate mycoplasma species within a specimen.[7]

Resistance of to the Class

As they lack a cell wall, all microorganisms in the class Mollicutes are resistant to cell wall synthesis inhibitors, such as b-lactams, glycopeptides and fosfomycin. They are also resistant to polymyxins, sulfonamides, trimethoprim, nalidixic acid and rifampin.[8,9] Rifampin resistance has been studied in the plant mycoplasma Spiroplasma citri and was found to be due to a natural mutation in the rpoB gene of the RNA polymerase β subunit, which prevents the antibiotic from binding to its target.[10] M. pneumoniae, like other human species studied, is resistant to linezolid (Table 1).

Species-specific Resistance

This type of intrinsic resistance concerns mainly the macrolide–lincosamide–streptogramin group and the ketolides (MLSK antibiotics).[8,9] Among human pathogenic mycoplasmas, M. pneumoniae and M. genitalium are susceptible to all MLSK antibiotics, except to lincomycin, which shows modest activity against these two species (Table 1). Ureaplasma spp. is susceptible to macrolides and ketolides, but resistant to lincosamides. The reverse is true for M. hominis, which is resistant to 14- and 15-membered ring macrolides and to telithromycin, but susceptible to the 16-membered ring macrolide josamycin and to lincosamides.[11–14] The genetic basis underlying intrinsic resistance to erythromycin has been studied by comparing the molecular target of macrolides (domains V and II of 23S rRNA) in M. hominis with that of M. pneumoniae, an erythromycin-susceptible species.[13] Resistance is due to a G (M. pneumoniae) to A (M. hominis) transition at position 2057 in the peptidyltransferase loop of the domain V region of 23S rRNA (Escherichia coli numbering). This transition has been found in the two ribosomal operons of M. hominis and is associated with macrolide resistance in other bacteria.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as: