TABLE 3.

Increases in ceftriaxone and cefixime resistancea

StrainCeftriaxoneCefixime
MIC (μg/ml)Fold increasebMIC (μg/ml)Fold increaseb
FA190.00060.0012
FA19 penA350.012200.12100
FA6140 penA350.24200.54.2
FA19 → FA6140 penA35400420
  • a The MICs of ceftriaxone and cefixime for FA19 (which is an antibiotic-susceptible strain), FA19 penA35 (which has an increase in resistance solely because of the penA35 allele), and FA6140 penA35 (which has an increase in resistance because of both penA35 and other resistance determinants) are shown.

  • b The increase was determined by dividing the MIC for the indicated strain by the MIC for FA19.