Susceptibility Assessment of Multidrug Resistant Bacteria to Natural Products.

OBJECTIVE: The aim of this study was to examine the effect of some natural compounds against multidrug-resistant bacteria. METHODS: Forty-three bacterial strains were collected. Disc diffusion and minimum inhibitory concentration (MIC) tests were carried out for natural compounds including quercetin, Acacia nilotica, Syzygium aromaticum, and Holothuria atra. Scanning electron microscope analysis and bacterial DNA apoptosis assays were performed. RESULTS: Staphylococcus aureus strains were resistant to imipenim, ampicillin, and penicillin. Most Escherichia coli strains were resistant to amoxicillin, clavulanat, and ampicillin. Finally, tigecycline was effective with Klebsiella pneumoniae and was resistant to all antibiotics. Only S aromaticum had an antibacterial effect on K pneumoniae. Most S aureus strains were sensitive to S aromaticum, A nilotica, and quercetin. All examined natural extracts had no effect on E coli. Holothuria atra had no effect on any of the strains tested. Minimum inhibitory concentration and minimum bactericidal concentration values for examined plants against S aureus were 6.25 to 12, 1.6 to 3.2, and 9.12 to 18.24 mg/mL, respectively. Syzygium aromaticum was active against K pneumoniae with an MIC of 12.5 mg/mL. Scanning electron microscope analysis performed after 24 and 48 hours of incubation showed bacterial strains with distorted shapes and severe cell wall damage. Syzygium aromaticum, quercetin, and A nilotica showed clear fragmentations of S aureus DNA. CONCLUSIONS: Current findings confirmed the beneficial effect of using natural products such as clove (S aromaticum), quercetin, and A nilotica as a promising therapy to overcome multidrug resistant bacteria.

Modulatory effects of levamisole and garlic oil on the immune response of Wistar rats: Biochemical, immunohistochemical, molecular and immunological study.

Levamisole (LEVA) and garlic are prevalent immunomodulators in humans and animals. Therefore, the present study aimed to examine the immunomodulatory effects of LEVA and garlic oil (GO) alone or in combination on the immune response of Wistar rats. A total of 24 male Wistar rats were allocated into four equal groups: Control group, which was given ad libitum access to food and water; and groups 2­4, which were orally administered LEVA [2.5 mg/kg body weight (BW) every 2 days], GO, (5 ml/kg BW daily), or LEVA plus GO, respectively for 4 consecutive weeks. Serum immunoglobulin (Ig)G and IgM levels were measured using a radial immunodiffusion assay. Serum cytokine levels, including interferon (IFN)-γ, interleukin (IL)-5 and tumor necrosis factor (TNF)-α, were measured using enzyme­linked immunosorbent assay kits. Total blood counts were measured automatically using a cell counter. Serum lysozyme enzymatic activity was determined by measuring the diameters of the zones of clearance relative to lysozyme. Immunohistochemical detection of CD4 and CD8 was carried out using the streptavidin-biotin-peroxidase method. Furthermore, the mRNA expression levels of IL­4, IL­5 and IL­12 were measured in the leukocytes and thymus gland by semi-quantitative polymerase chain reaction. The results revealed that LEVA increased serum levels of IFN­Î³, IL­5 and TNF­α cytokines, whereas co­administration of LEVA and GO decreased the stimulatory action of LEVA alone. LEVA and GO alone increased the serum levels of IgG, IgM and total blood cell counts, and co­administration of GO and LEVA inhibited the effects of LEVA. At the cellular level, in the spleen, LEVA increased immunoreactivity of CD4 and CD8, whereas co­administration of GO with LEVA decreased this strong expression. At the molecular level, in leukocytes, LEVA upregulated the mRNA expression levels of IL­2, IL­4 and IL­5, whereas GO alone downregulated mRNA expression. Co­administration of GO with LEVA inhibited the LEVA­induced upregulation of IL­2, IL­4 and IL­5 mRNA expression. In the thymus, both LEVA and GO upregulated the mRNA expression levels of IL­4 and IL­5, whereas LEVA alone did not affect IL­12 mRNA expression. Co­administration of GO with LEVA inhibited LEVA­induced upregulation of IL­4 and GO­induced upregulation of IL­12 expression, and had an additive upregulatory effect on IL­5 expression. In conclusion, LEVA stimulated T­helper (Th)1 cytokines, whereas GO stimulated a Th2 response, and co­administration of GO with LEVA inhibited the stimulatory effects of LEVA and balanced the Th1/Th2 response.