Table 2.

Susceptibilities of selected S. pneumoniae mutants to fluoroquinolonesa

StrainGenerationDescriptionMIC (μg/ml) of:
CIPCIP-RESSPARCLINGATGREPLEVMOXTROV
M3ParentWild type0.50.50.250.060.50.50.50.250.12
M26First stepParC Ser79→Alabmutant42.50.250.121120.50.25
M27Second stepParC Ser79→Ala efflux mutant643240.5816160.54
M30Second stepParC Ser79→Ala efflux mutant641620.5816484
M31Second stepParC Ser79→Ala efflux mutant161640.5816844
M4ParentWild typec 110.120.120.50.520.250.12
M16First stepEfflux mutant62.50.50.121120.250.25
M22First stepEfflux mutant1210.50.251120.50.25
  • a Abbreviations: CIP, ciprofloxacin; RES, reserpine; SPAR, sparfloxacin; CLIN, clinafloxacin; GAT, gatifloxacin; GREP, grepafloxacin; LEV, levofloxacin; MOX, moxifloxacin; and TROV, trovafloxacin.

  • b Ser-to-Ala mutation at position 79.

  • c Silent mutations at Val157 and Asp159 ingyrB.