Table 2.

Sequences of mutant marR genes in six clinical Mar mutants with different ofloxacin susceptibilities

StrainaOfloxacin MIC (μg/ml)Cyclo- hexane tolerancebMutation inmarR (nucleotide changed) at amino acidc:
S200.25+Ser (1724C→A)Ser (1751G→A)His (1853T→C)
M192+Stop codon inserted (1535G→T)Ser (1751G→A)His (1853T→C)
NH528Frameshift (Δ1751d)
HO1732+His (1725G→A)Ser (1751G→A)His (1853T→C)
HO9932+Met (1676C→A)
E2264+Ser (1590T→G)
  • a See Materials and Methods for strain designations.

  • b Cyclohexane tolerance of strains was tested on LB agar overlaid by the organic solvent and grown for 24 h at 30°C (33).

  • c See reference 10.

  • d Δ1751, nucleotide 1751 deleted.