The decreasing effectiveness of traditional antibiotics against resistant bacteria is a global public health. Combination between plant extract and antibiotics is one of the most important tools in the increasing of the effectiveness of many traditional antibiotics against pathogenic bacteria. The purpose of the current investigation to study the interaction between methanol extract of Moringa oleifera leaves (MML) and β-lactam antibiotics by agar diffusion method. Obtained results showed that MML (1.0 g/ml) had negative antibacterial activity against all tested strains. While its combinations with β-lactam antibiotics exhibited different interactions against them. Furthermore, the combinations of MML/imipenem, cefepime, ceftazidime or piperacillin exhibited indifferent interaction against Klebsiella sp., antagonistic interaction against E. coli &Pseudomonas sp. and synergistic interaction against Acinetobacter sp.. Thus, MML could be used as source for resistance-modifying agents against infectious multi-drug resistant Acinetobacter sp.
