Research Article

Antibacterial and Antibiotic-Modifying Activity of Methanol Extracts from Six Cameroonian Food Plants against Multidrug-Resistant Enteric Bacteria

Table 9

M1IC of different antibiotics after the association of the extract of bark from Persea americana at MIC/2, MIC/4 against ten MDR bacteria strains.

AntibioticBacterial strains and MIC (μg/mL) of antibiotics in the absence and presence of the extrac
Extract
concentration
PA124AG102AG100AtetEA289CM64KP55KP63NEA16PS2636BM47PBS (%)

CHL0128812825625632321664128
MIC/264 (0.5)4 (0.5)128 (1)256 (1)256 (1)32 (1)16 (0.5)16 (1)64 (1)64 (0.5)40
MIC/464 (0.5)8 (1)128 (1)256 (1)256 (1)32 (1)16 (0.5)16 (1)64 (1)128 (1)20

CIP0648>64>64>642<0.548<0.5
MIC/232 (0.5)4 (0.5)>64 (≥1)>64 (≥1)32 (<0.5)<0.5 (<0.25)<0.5 (≥1)4 (1)8 (1)<0.5 (≥1)40
MIC/432 (0.5)8 (1)>64 (≥1)>64 (≥1)>64 (≥1)<0.5 (<0.25)<0.5 (≥1)4 (1)8 (1)<0.5 (≥1)20

TET01616326443224232
MIC/28 (0.5)<1 (<0.062)64 (2)32 (0.5)<0.5 (<0.125)16 (0.5)1 (0.5)<0.5 (<0.125)2 (1)32 (1)70
MIC/48 (0.5)<1 (<0.062)64 (2)32 (0.5)<0.5 (<0.125)32 (1)2 (1)4 (1)2 (1)32 (1)40

ERY012881282568164161616
MIC/2128 (1)4 (0.5)16 (0.5)128 (0.5)8 (1)4 (0.5)4 (1)16 (1)16 (1)8 (0.5)50
MIC/4128 (1)8 (1)128 (1)128 (0.5)8 (1)16 (1)4 (1)16 (1)16 (1)8 (0.5)20

KAN012848323232<216168
MIC/2128 (1)4 (1)4 (0.5)32 (1)16 (0.5)8 (0.25)<2 (≥1)16 (1)4 (0.25)8 (1)40
MIC/4128 (1)4 (1)8 (1)32 (1)16 (0.5)16 (0.5)<2 (≥1)16 (1)16 (1)8 (1)20

STP0256>256>256128864816>25664
MIC/264 (0.25)256 (<1)>256 (≥1)128 (1)4 (0.5)64 (1)4 (0.5)16 (1)256 (<1)32 (0.5)60
MIC/464 (0.25)>256 (≥1)>256 (≥1)128 (1)8 (1)64 (1)8 (1)16 (1)>256 (≥1)32 (0.5)20

AMP0>256>256>256>256>256>256>256>256>256>256
MIC/2256 (<1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)128 (<0.5)>256 (≥1)256 (<1)>256 (≥1)30
MIC/4>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)00

CEF0>256>256>256>256>256>256>256>256>256>256
MIC/2>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)128 (<0.5)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)10
MIC/4>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)>256 (≥1)00

[TET: tetracycline, CIP: ciprofloxacin, STP: streptomycin, KAN: kanamycin, CHL: chloramphenicol, ERY: erythromycin, AMP: ampicillin, and CEF: cefepime]. strains: Escherichia coli [AG102, AG100Atet], Pseudomonas aeruginosa [PA124], Enterobacter aerogenes [CM64, EA27, EA289], Klebsiella pneumonia [KP55, KP63], Providencia stuartii [NAE16], and Enterobacter cloacae [BM47]. : percentage of bacteria strain on which synergism has been observed. Values in parenthesis are fractional inhibitory concentration (FIC) of the antibiotics after association with plants extract; S: synergy; I: indifference. The values in bold represent the cases of synergy between extract and antibiotic.