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Table 3 Minimal inhibitory and bactericidal concentrations of different sub-fractions

From: Bark extract of Cassia sieberiana DC. (Caesalpiniaceae) displayed good antibacterial activity against MDR gram-negative phenotypes in the presence of phenylalanine-arginine β-naphthylamide

Bacterial strains Sub-fractions and concentrations (μg/mL)
CSBc1 CSBc2 CSBc3
MIC MBC R MIC MBC R MIC MBC R
Escherichia coli
 ATCC8739 256 > 2 64 64 1 256 > 2
 AG102 nt nd 256 > 2 64 > 8
Klebsiella pneumoniae
 ATCC11296 64 > 8 128 > 4 nt nd
 KP55 nt nd nt nd nt nd
Enterobacter aerogenes
 ATCC13048 512 > 1 256 > 2 nt nd
 EA27 nt nd nt nd nt nd
Providencia stuartii
 ATCC29916 nt nd 256 > 2 256 > 2
 PS2636 nt nd 256 > 2 nt nd
Pseudomonas aeruginosa
 PA01 nt nd nt nd nt nd
 PA124 nt nd 128 128 1 nt nd
 PSBS (%) 30    70    30   
  1. MIC minimal inhibitory concentration, MBC minimal bactericidal concentration R: MBC / MIC ratio (a sample is considered as bacteriostatic or bactericidal when this ratio is > 4 or ≤ 4 respectively) (−): MIC or MBC > 512 μg/mL nt: not tested nd: not determined (as no MIC and MBC values were not observed till 512 μg/mL) PBSS: percentage of susceptible bacteria to substances CSBc1, CSBc2 and CSBc3 are sub-fractions from fraction CSBc