In vitro interaction of certain antimicrobial agents in combination with plant extracts against some pathogenic bacterial strains

Combinational Effect of Selected Medicinal Plants and Antibiotics Against Pathogenic Bacteria

<b>Background and Objective:</b> The emergence of antibiotic resistance is a primary global health concern. As a result, there is an urgent need for new strategies to combat antibiotic-resistant bacteria. One of these essential strategies is the combination of medicinal plants and antibiotics as an alternative to using antibiotics alone which was the objective of this article. <b>Materials and Methods:</b> Nine plant materials were collected from different Egypt localities and then extracted by water. Water extracts were filtered and added with Mueller-Hinton agar during preparation. Nine test bacteria and 13 standard antibiotics were used in the disc diffusion sensitivity method. <b>Results:</b> The activity of Amikacin was increased when combined with most different plant extracts against <i>Escherichia coli</i> while antagonistic against <i>Pseudomonas aeruginosa</i>. Aztreonam, Ceftriaxone, Gentamicin and Nalidixic acid antibiotics showed antagonistic or indifferent effects when combined with most different plant extracts against <i>E. coli</i>, <i>Klebsiella pneumonia</i> and <i>P. aeruginosa</i>. The synergistic effect was achieved in Aztreonam when combined with all plant extracts, while Nalidixic acid showed antagonistic when combined with most plant extracts against <i>Proteus mirabilis</i>. The antagonistic effect was achieved in Aztreonam, Ceftriaxone and Nalidixic acid when combined with <i>Achillea fragrantissima</i>, <i>Artemisia monosperma</i> and <i>Leptadenia pyrotechnica</i>, also Aztreonam with <i>Lycium shawii</i> extract against <i>Salmonella typhimurium</i>. The <i>A. fragrantissima</i> and <i>A. monosperma</i> increase the activity of Novobiocin and Vancomycin against <i>Bacillus cereus</i> and Ampicillin and Cefazolin against <i>Staphylococcus aureus</i> but Novobiocin activity increased with most plant extracts against <i>S. aureus</i>. <b>Conclusion:</b> The combinations of antibiotics with the extracts of medicinal plants displayed varying degrees of effects, synergistic, antagonistic and indifferent according to antibiotic type, plant extract and test organism.

Antibacterial activity of Lamiaceae plant extracts in clinical isolates of multidrug-resistant bacteria

The antibacterial activity of plant extracts of the Lamiaceae family was evaluated against clinical isolates of multi-resistant Gram-negative bacteria by broth microdilution technique. Promising results were obtained considering that all extracts were active for at least two bacterial species with MIC ranging from 0.5 to 2.0 mg/mL.

Phytosterols on growth performance, antioxidant enzymes and intestinal morphology in weaned piglets

BACKGROUND

Plant extracts have been used widely to improve growth, lower cholesterol, and exert antioxidative defense and antimicrobial activities in animal production. The present study aimed to investigate the effects of dietary phytosterols (PS) on growth performance, antioxidant enzymes and intestinal morphology in weaned piglets.

RESULTS

A total of 120 crossbred piglets, weighing 9.58 ± 0.26 kg, were randomly allocated to three treatments: control, PS (0.2 g kg^-1 ) and polymyxin E (0.04 g kg^-1 , antibiotic control). Compared to the control, PS or polymyxin E supplementation decreased diarrhea rate, serum cholesterol and malondialdehyde (MDA) of the piglets (P < 0.05). Liver MDA was significantly decreased in PS-fed piglets compared to the control (P < 0.05), although there was no difference between the control and polymyxin E-fed piglets. PS increased the villous height/crypt depth ratio of the duodenum and jejunum compared to the control (P < 0.05). Polymyxin E supplementation in piglets did not alter the villous height/crypt depth ratio but raised the villous height and crypt depth of the duodenum compared to the control (P < 0.05).

CONCLUSION

The results of the present study indicated that PS could decrease diarrhea rate, lower serum cholesterol, reduce lipid peroxidation and ameliorate intestinal morphology in weaned piglets. In addition, PS exerted better amelioration on intestinal morphology than polymyxin E in piglets. © 2017 Society of Chemical Industry.

Characterization, antifungal and cytotoxic evaluation of green synthesized zinc oxide nanoparticles using Ziziphus nummularia leaf extract

Zinc oxide nanoparticles (ZnO NPs) were synthesized using Ziziphus nummularia leaf extract. The characterization was done by various spectral analysis and antifungal (anti-candidal) activity against multidrug resistant clinical isolates and their cytotoxic potential was evaluated. The ZnO NPs were 17.33 nm in size and were spherical/irregular in shape. The antifungal activity of ZnO NPs was better than four standard azole antibiotics and they also showed potent cytotoxic effect against HeLa cancer cell line. The results strongly suggest the applicability of green synthesized ZnO NPs as antifungal agent and also its use in cancer diagnosis and treatment.

Antibacterial Effects of Cissus welwitschii and Triumfetta welwitschii Extracts against Escherichia coli and Bacillus cereus

Antibiotic resistance has increased sharply, while the pace for the development of new antimicrobials has slowed down. Plants provide an alternative source for new drugs. This study aimed to screen extracts from Cissus welwitschii and Triumfetta welwitschii for antibacterial activity against Escherichia coli and Bacillus cereus. The tests conducted included a susceptibility determination test, analysis of the effect of T. welwitschii on cell wall integrity, and transport across the membrane. It was found that the T. welwitschii methanol extracts were more effective than the water extracts and had the lowest minimum inhibitory concentration and minimum bactericidal concentration at 0.125 mg/mL and 0.5 mg/mL, respectively, against E. coli and B. cereus. The C. welwitschii extract caused the most drug accumulation in E. coli. In B. cereus, no significant drug accumulation was observed. Nucleic acid leakage in B. cereus and E. coli and protein leakage in E. coli were observed after exposure to the T. welwitschii extract. The extracts from T. welwitschii had greater antibacterial activity than the extracts from C. welwitschii. T. welwitschii may be a potential source of lead compounds for that could be developed into antibacterial agents.