TABLE 1.

23S and L4 mutations and characterization of mutated isolatese

Strain no.Mutation in 23S rRNA gene at:No. of mutated genesfMutation in protein L4 (position 69GTG71b)Acquired macrolide resistance genePFGE subtypecSero- typeSpecimen typeMIC (μg/ml) of:
A2059aC2611aAzithromycinErythromycinClarithromycinClindamycinLincomycinSpiramycinTelithromycin (HMR 3647)HMR3004Dalfopristin (streptogramin A)Quinupristin (streptogramin B)Quinupristindalfopristin (RP59500)Chloramphenicol
r330dwtwt0wtSNDNDEar0.50.06310.12520.50.0310.063>64814
r744dwtwt0wterm(B)ND23FEar>512>512>512>64>128>5120.0630.125>6432216
r490Cwt4wtNoneA14Sinus1282565120.5165120.0630.25321612
r678Cwt4wtNoneA14Ear512>512>512116>5120.0630.5643222
r684Cwt4wtNoneL14Ear512>512>512116>5120.1250.5643212
r733Cwt4wtNoneA14Not known512>512>512116>5120.1250.5643222
r1152Cwt4wtNoneA14Nose512512>5121165120.1250.5643222
r1317Cwt3wtNoneF23Sinus512>512>512232>5120.1250.5>643222
r506Cwt2wtNoneA14Ear128256512185120.0630.25643222
r771Gwt2wtNoneI15Sputum>512256>512232>5120.250.5643244
r1341Gwt2wtNoneH14Blood>512642561165120.0630.125641622
r1045wtG4wtNoneN6BEar128>512>51218160.528>6424
r791wtwt0TPSNoneJ19AThroat>512>512>5120.252640.250.5>641624
ATCC 49619dwtwt0NDNone0.50.1250.50.12510.50.0160.12564412
  • a Nucleotides in the wild-type 23S rRNA gene.

  • b Amino acids in the wild-type L4 protein.

  • c Different PFGE subtypes are listed in alphabetical order.

  • d Control strain.

  • e Abbreviations: S, erythromycin-susceptible strain; wt, wild type; ND, not done.

  • f Out of four examined.