TABLE 1.

Ribosomal mutations observed in spontaneous Azmr isolates of C. caviaea

Day (postinoculation) of recovery from animalWild-type clonal strainbFrequency of spontaneous AZM resistancecNo. of isolates with mutation at indicated position in 23S rRNA gene (representative strain)
A2058CA2058GA2059CA2059G
9SP1(4.3 ± 7.1) × 10−96 (SP1AZ1)000
SP2(2.7 ± 7.1) × 10−9001 (SP2AZ1)0
SP510−9003 (SP5AZ1)0
SP610−91 (SP6AZ1)01 (SP6AZ2)0
12SP3(2.9 ± 3.4) × 10−823 (SP3AZ1)000
SP47.7 × 10−101 (SP4AZ1)000
SP710−901 (SP7AZ1)00
SP8(2.0 ± 2.8) × 10−94 (SP8AZ1)001 (SP8AZ3)
SP9(4.5 ± 6.3) × 10−9001 (SP9AZ1)0
SP102.0 × 10−91 (SP10AZ2)01 (SP10AZ1)0
  • a Strains in bold were used in in vitro and in vivo studies.

  • b Infectious particles from a single plaque were expanded during three to four developmental cycles to obtain clonal populations of C. caviae.

  • c The frequencies of appearance of resistant mutants are relative to the total number of PFU infecting a confluent mouse fibroblast monolayer growing in a 60-mm dish ± the standard deviation.