Heterogeneous macrolide resistance and gene conversion in the pneumococcus.
A macrolide-resistant clinical isolate of Streptococcus pneumoniae with 23S rRNA mutations showed a heterogeneous phenotype and genotype. The mutant 23S rRNA genes from this isolate transformed susceptible strain R6 to resistance. Culture of resistant strain R6 in the absence of antibiotic pressure showed gene conversion to occur between the four 23S rRNA alleles, resulting in reversion to susceptibility with the resistant phenotype showing a fitness cost. These data explain the disappearance on subculture of heterogeneous macrolide resistance in the pneumococcus.
Wolter
Nicole
N
Respiratory and Meningeal Pathogens Research Unit, National Institute for Communicable Diseases, Private Bag X4, Sandringham, 2131, South Africa. nicolew@nicd.ac.za
Smith
Anthony M
AM
Farrell
David J
DJ
Klugman
Keith P
KP
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005785:Gene Conversion / Q000187:drug effects*; D006801:Humans; D018942:Macrolides / Q000494:pharmacology*; D011008:Pneumococcal Infections / Q000382:microbiology; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics; D012338:RNA, Ribosomal, 23S / Q000737:chemistry / Q000235:genetics*; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism
D000900:Anti-Bacterial Agents; D018942:Macrolides; D012329:RNA, Bacterial; D012338:RNA, Ribosomal, 23S