TABLE 5.

Antimicrobial susceptibilities of transconjugants grouped by presence of the armA or rmtB gene and by plasmid incompatibility groupa

Antimicrobial agentMIC50 for isolates with the indicated gene and Inc plasmidb:
armA (n = 143)rmtB (n = 47)
FIIAs (n = 20)L/M (n = 37)A/C (n = 7)F (n = 7)NI (n = 75)A/C (n = 41)F (n = 6)
Ampicillin512>512>512>512>512>512>512
Aztreonam<18<1<1328<1
Ceftazidime<12<1<1322<1
Cefotaxime<164<1<1464<1
Cefepime<18<1<1<18<1
Cefoxitin324123244
Ciprofloxacin0.250.030.0150.030.250.0150.25
Chloramphenicol4464441284
Streptomycin25645122562562564
Sulfamethoxazole1616>5121616>51216
Trimethoprim<1<1<18<1>512<1
Tetracycline<1<11<1<132<1
  • a Groups with fewer than five strains were excluded from calculations of MIC50s.

  • b Numbers of strains included in each group are shown in parentheses. NI, not identified.