Table 4.

Copy numbers of rRNA operons in pathogens for which macrolide resistance mechanisms have not been reporteda

OrganismNo. of rRNA operonsReference(s)
Chlamydia pneumoniae 1 50
Coxiella burnetii 1 3
Mycobacterium leprae 1 118
Mycobacterium tuberculosis 1 13
Mycoplasma genitalium 1 48
Mycoplasma hyopneumoniae 1 130
Rickettsia prowazekii 1 8
Borrelia burgdorferi 2b 33, 115
Chlamydia trachomatis 2 46
Leptospira interrogans 2 49
Mycobacterium celatum 2 102
Mycoplasma gallisepticum 2c 25
Bordetella pertussis 3 89
Campylobacter jejuni-C. coli 3 71, 131
Moraxella catarrhalis 4 91
Neisseria meningitidis 4 153
Pseudomonas aeruginosa 4 108
Bacillus cereusgroup6–10 101
Haemophilus influenzae 6 77
Listeria monocytogenes 6 86
Salmonellaspp.7 78
Vibrio cholerae 9 75
  • a Most of these bacteria are sensitive to macrolide antibiotics, at least in vitro (see, e.g., references12, 15, 24, 65, 72, 81, 100, 114, 127, and135). For M. tuberculosis, some controversy exist about the effect of macrolides in vivo (81,135). It is expected that macrolide resistance conferred by rRNA mutations is more likely to arise in the bacteria in the upper portion of the table (see text).

  • b One 16S RNA gene and two 23S RNA genes.

  • c One operon of rRNA genes plus a separate set of 16S and 23S RNA genes.