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Table 5 MIC of antibiotics after the association of the extract of Newbouldia laevis and Polysicas fulva at MIC/2 and MIC/5 against selected MDR bacteria

From: In vitro antibacterial and antibiotic-potentiation activities of the methanol extracts from Beilschmiedia acuta, Clausena anisata, Newbouldia laevis and Polyscias fulva against multidrug-resistant Gram-negative bacteria

Antibioticsa Extract and concentration Bacterial strainsb, MIC (μg/mL) of antibiotics in the absence and presence of the extract and FIC in parenthesis PBSS (%)
   AG102 AG100ATET EA27 CM64 KP55 NAE16 BM67 PA01 PA124  
  Newbouldia laevis           
CIP 0 4 64 4 64 4 128 32 16 32  
  MIC/2 4 (1)I 64 (1)I 2 (0.50)S 32 (0.50)S 4 (1)I 128 (1)I 16 (0.50)S 16 (1)I 32(1)I 3/9 (27.27 %)
  MIC/5 4 (1)I 64 (1)I 2 (0.50)S 64 (1)I 4 (1)I 128 (1)I 32 (1)I 16 (1)I 32(1)I 1/9 (11.11 %)
TET 0 8 64 64 32 2 64 32 64 16  
  MIC/2 4 (0.50)S 16 (0.25)S 32 (0.50)S 4 (0.13)S 2 (1)I 32 (0.50)S 16 (0.50)S 32 (0.50)S 8(0.50)S 8/9 (88.89 %)
  MIC/5 8 (1)I 32 (0.50)S 64 (1)I 8 (0.25)S 0.50 (0.25)S 64 (1)I 32 (1)I 64 (1)I 8(0.50)S 4/9 (36.36 %)
KAN 0 - 16 128 4 16 16 64 4 128  
  MIC/2 4 (˂0.03)S 8 (0.50)S 64 (0.50)S 2 (0.50)S 16 (1)I 8 (0.50)S 32 (0.50)S 2 (0.50)S 32(0.25)S 8/9 (88.89 %)
  MIC/5 64 (˂0.50)S 16 (1)I 128 (1)I 4 (1)I 1 (0.06)S 8 (0.50)S 32 (0.50)S 4 (1)I 64(0.50)S 5/9 (55.55 %)
AMP 0 - - - - - - - - -  
  MIC/2 -(≥1) -(≥1) 256 (˂1)S -(≥1) -(≥1) 256 (˂1)S -(≥1) -(≥1) -(>1) 2/9 (22.22 %)
  MIC/5 -(≥1) -(≥1) -(≥1) -(≥1) 256 (˂1)S - (≥1) -(≥1) -(≥1) -(>1) 1/9 (11.11 %)
CHL 0 32 64 64 - 8 64 128 16 128  
  MIC/2 16 (0.50)S 32 (0.50)S 64 (1)I 64 (˂0.25)S 4 (0.50)S 16 (0.25)S 32 (0.25)S 4 (0.25)S 128(1)I 7/9 (77.78 %)
  MIC/5 32 (1)I 64 (1)I 64 (1)I 128 (˂0.50)S 1 (0.13)S 32 (0.50)S 64 (0.50)S 16 (1)I 128(1)I 4/9 (36.36 %)
  Polyscias fulva           
CIP 0 4 64 4 64 4 128 32 16 32  
  MIC/2 4 (1)I 64 (1)I 2 (0.50)S 64 (1)I 4 (1)I 128 (1)I 2 (0.06)S 8 (0.50)S 32(1)I 3/9 (27.27 %)
  MIC/5 4 (1)I 64 (1)I 2 (0.50)S 64 (1)I 4 (1)I 128 (1)I 4 (0.13)S 16 (1)I 32(1)I 2/9 (22.22 %)
TET 0 8 64 64 32 2 64 32 64 16  
  MIC/2 2 (0.25)S 32 (0.50)S 32 (0.50)S 4 (0.13)S <0.50 (<0.25)S 32 (0.50)S 8 (0.25)S 2 (0.03)S 8(0.50)S 9/9 (100 %)
  MIC/5 4 (0.50)S 64 (1)I 32 (0.50)S 16 (0.50)S 2 (1)I 32 (0.50)S 32 (1)I 32 (0.50)S 8(0.50)S 6/9 (66.67 %)
KAN 0 - 16 128 4 16 16 64 4 128  
  MIC/2 8(˂0.06)S 8 (0.50)S 64 (0.50)S 2 (0.50)S 2 (0.13)S 8 (0.50)S 32 (0.50)S <1 (<0.25)S 64(0.50)S 9/9 (100 %)
  MIC/5 64 (˂0.50)S 16 (1)I 128 (1)I 4 (1)I 16 (1)I 8 (0.50)S 32 (0.50)S 4 (1)I 64(0.50)S 4/9 (36.36 %)
AMP 0 - - - - - - - - -  
  MIC/2 128 (˂0.50)S -(≥1) 256 (˂1)S -(≥1) 256 (˂1)S 256 (˂1)S -(≥1) 256 (˂1)S -(>1) 5/9 (55.55 %)
  MIC/5 256 (˂1)S -(≥1) -(≥1) -(≥1) -(≥1) -(˃1) -(≥1) -(≥1) -(>1) 1/9 (11.11 %)
CHL 0 32 64 64 - 8 64 128 16 128  
  MIC/2 16 (0.50)S 64 (1)I 64 (1)I 128 (˂0.50)S 4 (0.50)S 8 (0.13)S 64 (0.50)S 2 (0.13)S 64(0.50)S 7/9 (77.78 %)
  MIC/5 32 (1)I 64 (1)I 64 (1)I 256 (˂1)S 4 (0.50)S 16 (0.25)S 64 (0.50)S 16 (1)I 64(0.50)S 5/9 (55.55 %)
  1. aAntibotics [TET tetracycline, CIP ciprofloxacin, KAN kanamycin, CHL chloramphenicol, AMP ampicillin]. bBacterial strains: Escherichia coli [AG102, AG100Atet], Pseudomonas aeruginosa [PA01, PA124], Enterobacter aerogenes [CM64, EA27], Enterobacter cloacae [BM67], Klebsiella pneumoniae [KP55], Providencia stuartii [NAE16]. cPBSS percentage of bacteria strain on which synergism has been observed, NA not applicable
  2. (): fold increase in MIC values of the antibiotics after association with plants extract, S synergy, I indifference, na not applicable, FIC fractional inhibitory concentration, (−): >256 μg/mL, 0: no extract (only antibiotic tested)