عنوان مقاله [English]
Due to inappropriate use of antibiotics, the bacterial species have become resistant to antimicrobial medicines and treatments to health problems. Medicinal plants and derivatives are a good source for treatment and are effective against drug resistance. In this study, the effect of Aloe vera on biochemical properties and cell structure of drug-resistant E. coli was studied by electron microscopy. Aloe vera aqueous extract was produced by distillation method and the minimum growth inhibitory concentration (MIC) was determined by diffusion disk method and dilution microplate for drug-resistant E. coli. The effect of extract on biochemical properties of bacterial cultures was analyzed using blood agar, eosin methylene blue (EMB), biochemical tests IMVIC, citrate test, SIM test and urease test. The possible change in cell structure compared with control, was assessed in consecutive extract concentrations using scanning optical microscopy, and the first concentration altering the structure was determined. At this concentration, the exact structure of drug-resistant and sensitive
E. coli strains was studied using TEM, negative staining and section methods. Kirby-Bauer method results demonstrated that drug-resistant E. coli (ESBL) was resistant to the studied antibiotics. MIC of 4 mg of drug-resistant E. coli was determined. At this concentration, up to 30 minutes of combination of extract and bacteria, the results of all biochemical tests were unchanged. After this time, tests of citrate, indole, mobility and OF were negative and TSI was without gas production and alk/alk. Optical microscopy results showed that the extract can destroy, reduce size and assembly of bacteria, induce to form cocobacilli and change the staining. Comparison of stained-resistant isolates and negative control samples in electron microscopy indicated the visibility of the bacterial assembly and asymmetric divisions from the cell pole. The results of two different morphology in cross-section of Escherichia showed an ordinary and dull form that is larger and has a thickness of 2.3nm.. The aqueous extract prepared from the plant Aloe vera, had an equivalent effect to or a better effect than the commonly used antibiotics on bacteria isolated from patients with infectious matters. Therefore, appropriate drugs made of plants may be used to treat resistant infections..