Prediction of resistance to erythromycin in the genus Rickettsia by mutations in L22 ribosomal protein.
OBJECTIVE
Typhus group (TG) rickettsiae are naturally susceptible to erythromycin whereas spotted fever group (SFG) rickettsioses are not. The aim of this study was to compare in silico genetic determinants known to be associated with resistance to macrolide compounds.


RESULTS
Available sequences of the 23S RNA gene, and L4 and L22 ribosomal proteins of rickettsial strains were aligned and compared using in silico methods. Although there were no sequence differences in domain V of the 23S RNA gene and in the conserved region of the L4 ribosomal protein gene, we found that TG rickettsiae had a triple amino acid difference in the highly conserved region of the L22 ribosomal protein compared with the SFG rickettsiae.


CONCLUSIONS
We believe that the triple amino acid difference in the L22 ribosomal protein found in this study may explain the difference in susceptibility to erythromycin among the Rickettsia genus. Genome analysis may help to predict possible molecular mechanisms of resistance for fastidious and intracellular bacteria and cloning and expression of such proteins should be investigated in the future in order to prove our hypothesis.
Unité des Rickettsies, CNRS UMR 6020, IFR 48, Faculté de Médecine, Université de la Méditerranée, 27 Bd Jean Moulin, 13385 Marseille Cedex 05, France.
J M
JM
Rolain
D
D
Raoult
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004917:Erythromycin / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009154:Mutation; D011237:Predictive Value of Tests; D012269:Ribosomal Proteins / Q000235:genetics*; D012281:Rickettsia / Q000187:drug effects / Q000235:genetics*; D016415:Sequence Alignment
D001426:Bacterial Proteins; D012269:Ribosomal Proteins; D004917:Erythromycin