The high cross-transmission in methicillin resistant Staphylococcus aureus between healthy and patient communities.

Background and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the main causes of high mortality and morbidity in hospitals. This study was aimed to examine virulence factors, molecular typing, and the antibiotic resistance pattern of MRSA isolates in hemodialysis patients and healthy communities. Materials and Methods: Total of 231 and 400 nasal samples were obtained from hemodialysis patients and healthy communities, respectively. Virulence factors profile was examined in two groups by PCR reaction. Enterobacterial Repetitive Intergenic Consensus (ERIC-PCR) was used as a molecular typing approach. Results: Overall, 35.49% (82/231) of hemodialysis patients were positive for S. aureus, and 47.56% (39/82) of isolates were positive for mecA. In a healthy community, 15% (60/400) of samples were positive for S. aureus, and 36.66% (22/60) were positive for mecA. The frequency of MDR was significantly higher in patients group (p-value < 0.00001). The frequency of pvl (p.value = 0.003932, P<0.05) and tsst-1 (p.value = 0.003173, p < .05) were significantly higher in patients group. The highest frequency virulence factors in healthy individuals were related to hla (68.33%, 41/60), hlb (53.33%, 32/60), and Acme/arcA (46.66%) genes. Two groups were clustered by the ERIC-PCR method into 7 clusters and 2 single isolate with a 0.74 similarity index. Based on the results, each cluster was combination with healthy and patient isolates. Conclusion: Our findings indicate a notable variation in the frequency of virulence factors between S. aureus isolates obtained from dialysis patients and the healthy community.

Effect of aberrant DNA methylation on cancer stem cell properties.

DNA methylation, as an epigenetic mechanism, occurs by adding a methyl group of cytosines in position 5 by DNA methyltransferases and has essential roles in cellular function, especially in the transcriptional regulation of embryonic and adult stem cells. Hypomethylation and hypermethylation cause either the expression or inhibition of genes, and there is a tight balance between regulating the activation or repression of genes in normal cellular activity. Abnormal methylation is well-known hallmark of cancer development and progression and can switch normal stem cells into cancer stem cells. Cancer Stem Cells (CSCs) are minor populations of tumor cells that exhibit unique properties such as self-regeneration, resistance to chemotherapy, and high ability of metastasis. The purpose of this paper is to show how aberrant DNA methylation accumulation affects self-renewal, differentiation, multidrug-resistant, and metastasis processes in cancer stem cells.

The molecular characterization of colistin-resistant isolates of Acinetobacter baumannii from patients at intensive care units.

Background and Objectives: The objective of this study was to determine molecular characterization and genetic diversity of colistin-resistant A. baumannii clinical isolates in Intensive Care Unit hospitalized patients. Materials and Methods: A total of 127 A. baumannii clinical isolates were evaluated for antimicrobial susceptibility. PCR reaction and sequencing were performed for the detection of mutations in pmrAB and lpx ACD genes. Results: Based on antimicrobial susceptibility testing, 40.94% and 33.85% of the isolates were MDR and XDR respectively whereas 3.93% of them were found to be PDR. Results of agar dilution MIC and E-test indicated that 76% of the isolates were sensitive to colistin. All of the isolates were positive for bla OXA-51 and 50% of them were positive for both bla OXA-23 -like and bla OXA-143 -like genes while only 25% of the isolates were positive for bla OXA-72 . None of them were positive for the bla OXA-58 -like gene. There is no mutation in pmrA. The V162A substitution for pmrB gene was repeated in two isolates, and E394D and Y292H substitutions in lpxA were observed in two isolates; also, C120R and F165L substitutions in lpxC gene was repeated in two isolates. Analysis of phylogenetic tree based on alterations in lpxACD and pmrB genes indicated the appearance of new isolates compared to the reference strain ATCC17978 A. baumannii isolates. Conclusion: The present study indicated the prevalence of MDR and XDR A. baumannii isolates and the emergence of PDR isolates in the northwest portion of Iran. The appearance of colistin-resistant isolates with new mutations in pmrB, lpxACD genes indicates new resistance mechanisms.

Astaxanthin protects mesenchymal stem cells from oxidative stress by direct scavenging of free radicals and modulation of cell signaling.

Recent evidence has shown that mesenchymal stem cells (MSCs) play vital roles in cell therapy of ischemia/hypoxia damaged tissues. However, after the transplantation, they might undergo apoptosis due to oxidative stress. Thus, some strategies have been developed to support stem cells in harsh conditions, including pre-treatment of the cells with antioxidants. Of various antioxidants, in this study, astaxanthin (ATX) was used to protect adipose-derived MSCs against oxidative stress. The MSCs were exposed to different doses of hydrogen peroxide, and then the expression of key genes involved in the redox signaling pathway was studied, including nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NADPH quinine oxidoreductase 1 (NQO1). The balance of intracellular reactive oxygen species was detected with the H2DCFDA molecular probe. Additionally, for the detection of apoptosis and protective effect of ATX, the DAPI/Phallacidin and annexin V cell staining were performed. The results of cellular studies revealed that ATX reduced the H2O2-induced cell apoptosis and oxidative stress. Furthermore, after the induction of oxidative stress, the cells' native antioxidants (HO-1 and NQO1) were overexpressed but they were modulated with ATX treatments (p < 0.023). Based on our findings, ATX could increase the expression of Nrf2 as a key transcription factor of antioxidant enzymes (p < 0.05). These findings support the notion that ATX can act as an effective antioxidant in the pre-treatment of MSCs before cell therapy. Thus, to enhance the viability of stem cells during the transplantation in harsh conditions, the concurrent use of ATX in cell therapy modalities is proposed.

Protective effect of bacterial lipase on lipopolysaccharide-induced toxicity in rat cardiomyocytes; H9C2 cell line.

Introduction: Cardiovascular system is highly sensitive to LPS-induced oxidative damage. This study aimed to show the inhibitory effect of bacterial Lipase on LPS-induced cardiomyoblasts toxicity. Methods: Rat cardiomyoblasts H9C2 were classified into Control, LPS (cells received 0.1, 1 and 10 µg/mL LPS) and LPS+ Lipase groups. In LPS+Lipase group, different concentrations of lipopolysaccharide were pre-incubated with 5 mg/mL bacterial lipase at 37˚C overnight prior to cell treatment. After 72 hours, cell viability was assessed by MTT assay. The expression of key genes related to toll-like receptor signaling pathways was assessed by real-time PCR assay. Percentage of fatty acids was evaluated in each group using gas chromatography assay. The levels of NO was also measured using the Griess reaction. Results: Data showed H9C2 cells viability was decreased after exposure to LPS in a dose-dependent manner (P < 0.05). Incubation of LPS with lipase increased cell survival rate and closed to near-to-control levels (P < 0.05). Lipase had the potential to blunt the increased expression of IRAK and NF-κB in cells after exposure to the LPS. Compared to the LPS group, lipase attenuated the increased level of NO-induced by LPS (P < 0.05). Gas chromatography analysis showed the reduction of saturated fatty acids in cells from LPS group while the activity of lipase prohibited impact of LPS on cell fatty acid composition. LPS decreased the ability of cardiomyoblasts to form colonies. Incubation of LPS with lipase enhanced clonogenic capacity. Conclusion: Reduction in lipopolysaccharide-induced cytotoxicity is possibly related to lipase activity and reduction of modified lipopolysaccharide with toll-like receptor.

Nasal and extra nasal MRSA colonization in hemodialysis patients of north-west of Iran.

OBJECTIVES: Methicillin resistant Staphylococcus (S.) aureus colonization is one of the main causes of serious infections in hemodialysis patients. This cross-sectional study was performed to examine prevalence of MRSA colonization and evaluation of risk factors in hemodialysis patients. A total of 560 swab samples from nasal, the skin around catheter and throat were collected from 231 hemodialysis patients in Tabriz. The standard biochemical tests were used for identification of S. aureus isolates. Antimicrobial susceptibility profile was determined against 11 antibiotics by the disk diffusion method. Phenotypic test of S. aureus was performed using novobiocin 30 µg/disc, and methicillin sensitivity test was performed by cefoxitin 30 µg/disc. RESULTS: Overall, 50.65% (118/231) hemodialysis patients were positive for S. aureus which 34.93% (80/231) of patients were MRSA carriage. The MRSA colonization in patients with a catheter (44.06%) was more than individuals utilizing a fistula (24.57%, p = 0.030). Among sampling sites, the highest MRSA was related to nasal samples (30.70%, p < 0.00001). Extra nasal colonization of S. aureus was observed in 12.71% patients. The highest rates of resistance were observed against ampicillin (93.98%) and the highest sensitivity was against linezolid antibiotic (5.42%). These findings highlight the necessity of prophylaxis against S. aureus in individuals under dialysis.

Culture filtrate ether extracted metabolites from Streptomyces levis ABRIINW111 increased apoptosis and reduced proliferation in acute lymphoblastic leukemia.

Despite the advances in the discovery of various types of anticancer drugs for curing acute lymphoblastic leukemia (ALL), their toxicity and unfavorable side effects remained as big limitations for therapeutical applications. In this regard, natural products such as Streptomyces -derived agents have shown potential applications as anticancer drugs. The present study deals with evaluating the anti-carcinogenic activity of the ether extracted metabolites derived from Streptomyces on nalm-6 and molt-4 ALL cell lines. MTT assay was performed to evaluate the cytotoxicity effect of Streptomyces sp on nalm-6 and molt-4 cell lines. Apoptosis and proliferation were evaluated by Flow cytometry. Quantitative real-time RT-PCR (qRT-PCR) and western blot were performed to investigate the effect of these metabolites on the mRNA and protein expression levels of P53, Bax, and Bcl2. In both cell lines, extracted metabolites significantly inhibited cell growth and increased apoptosis. Although P53, Bax mRNA and protein expressions were increased, Bcl-2 expression decreased in treated cells compared with control. In addition, the G0/G1 arrest of Nalm-6 cells was induced. These findings of this work show that the ether-extracted metabolites from Streptomyces levis ABRIINW111 can be used as an anti-carcinogenic for acute lymphoblastic leukemia cells.

Extracted metabolite from Streptomyces Levis ABRIINW111 altered the gene expression in colon cancer.

AIM: In this study we attempt to indicate anti-carcinogenic influence of ether extracted metabolites of Streptomyces Levis sp. on gene expression in colon cancer. BACKGROUND: Colon cancer is one of the most prevalent cancers worldwide. In recent decades, researchers have been seeking the treatment for cancer. Natural products are valuable compounds with fewer side effects in comparison to chemotherapy drugs. METHODS: Secondary metabolites were extracted with the inoculation of bacterial sample in Mueller Hinton Broth. MTT assay was done to evaluate the cytotoxicity effect of metabolites on SW480 cells. qRT-PCR was performed to observe effects of metabolites on Bcl-2, P53, SOX2, KLF4, ß-Catenin, SMAD4, K-ras, BRAF genes expression in colon cancer. RESULTS: The metabolites exhibited cytotoxic effects on colon cancer in a dose/time dependent manner (P < 0.001). After 48 h treatment, fold expression of Bcl-2, SOX2, ß-catenin, K-ras, BRAF genes fold of expression were decreased, whereas P53, KLF4, SMAD4 genes were increased in treated cells (P < 0.001). CONCLUSION: These findings indicate that ether extracted metabolites of Streptomyces Levis ABRIINW111 have anti-carcinogenic effects on colon cancer.

Novel Recombinant Traceable c-Met Antagonist-Avimer Antibody Mimetic Obtained by Bacterial Expression Analysis.

BACKGROUND: Avimers are originally types of artificial proteins with multiple binding sites for specific binding to certain antigens. Various radioisotopes and nanoparticles link these molecules, which are widely used in early detection in tissue imaging, treatment and study on carcinogenesis. Among these, c-Met antagonist avimer (C426 avimer), with ability to bind the c-Met receptor of tyrosine kinase (RTK) is an attractive candidate for targeted cancer therapy. In this study, a novel traceable C426 avimer gene was designed and introduced by adding the 12nt tracer binding site encoded four specific amino acid residues at the C-terminal region of C426 avimer coding sequence. METHODS: The 282 bp DNA sequence encoded 94aa avimer protein was synthesized and sub-cloned into prokaryotic pET26b expression vector. The expression of the mature peptide encoding the traceable avimer molecule was carried out in Escherichia coli strain BL21 using IPTG (Isopropyl ß-D-1-thiogalactopyranoside) induction process. The expression level of the 11 kDa traceable avimer was studied by SDS-PAGE, western blot and ELISA analysis. RESULTS: Docking analysis of C426 avimer protein and its ligand c-Met showed that the traceability related changes happened at the best conformation and optimal energy. The SDS-PAGE, western blotting and ELISA analysis results demonstrated that the expression of the 11 kDa C426 avimer molecule was detectable without any degradation compared with the control group. CONCLUSION: Concerning the consequences of this work, this new approach can be widely used in the medical field and provide an opportunity to evaluate the affinity and traceability features.

Streptomyces Levis ABRIINW111 Inhibits SW480 Cells Growth by Apoptosis Induction.

Purpose: Streptomyces sp., a dominant genus in Actinomycetes, is the source of a wide variety of secondary metabolites. Microbial metabolites can be utilized as novel anticancer agents; with fewer side effects. The present article illustrated the anti-carcinogenic effect of the ether extracted organic metabolites derived from Streptomyces bacteria on SW480 colon cancer cell line. Methods: MTT assay was performed in order to investigate the cytotoxicity effect of metabolites on SW480 cells. Apoptosis and cell cycle arrests were measured by flowcytometry. Morphological changes were indicated by Propidium iodide staining andP53 gene expression was evaluated by real-time PCR. Results: Streptomyces Levis ABRIINW111 inhibited cell growth, increased Caspases 3 and reduced Ki67 expression in a concentration/time-dependent manner in SW40 cells. Metabolites increased subG1 phase (apoptosis) and also cell cycle arrest in G1, G---2/M and S phase. P53 gene expression followed Sw480 cells treatment significantly. Conclusion: Streptomyces sp. metabolites have anti-carcinogenic effect on colon cancer cells. Streptomyces Levis ABRIINW111 metabolites are a candidate for Colon cancer treatment.

Efficiency and cytotoxicity analysis of cationic lipids-mediated gene transfection into AGS gastric cancer cells.

In this effort, we provided comparative study on optimization of transfection conditions for AGS human gastric cancer cell line using two commercial non-liposomal cationic lipids. Using reporter vector pEGFP-N1, transfection efficiency of Attractene™ and X-tremeGENE HP™ transfection reagents in terms of cell densities and DNA/reagent ratios was determined in AGS cells by flow cytometry and fluorescence microscopy. In addition, influence of transfection reagents on direct cytotoxicity and cell viability was respectively, measured using lactate dehydrogenase (LDH) leakage and MTT assays. Provided that the transfection rate of 29% and the mean fluorescence intensity of 437.5, the DNA/reagent ratio of 0.4/1.5 was selected as the optimal condition using Attractene™, whereas the optimum condition using X-tremeGENE HP™ was obtained by the ratio of 1/2 with a higher transfection rate of 36.9% and an MFI of 833. Very low direct cytotoxicity (<5% and 6-9% using Attractene™ and X-tremeGENE HP™, respectively) and high cell viability (74.5-95.5% versus 68-75%) showed the biodegradable attribute for both transfection reagents. Altogether, X-tremeGENE HP™ exhibited superiority over Attractene™ as a transfection reagent for AGS cells. In the present research, we have established the optimized protocols for efficient transfection of AGS cells with potential applications in gene function and expression studies as well as gene therapy.

Lactobacillus plantarum induces apoptosis in oral cancer KB cells through upregulation of PTEN and downregulation of MAPK signalling pathways.

Introduction: The oral tumor is the sixth most prevalent type of cancer worldwide and the second leading cause of cancer-related mortality. Although chemotherapy and immunotherapy are the main strategies for the treatment of oral cancer, an emergence of inevitable resistance to these treatment modalities is the major drawback that causes recurrence of the disease. Nowadays, probiotics have been suggested as adjunctive and complementary treatment modalities for improving the impacts of chemotherapy and immunotherapy agents. Probiotics, the friendly microflora in our bodies, contribute to the production of useful metabolites with positive effects on the immune system against various diseases such as cancer. Methods:Lactobacillus plantarum is one of the most important bacteria, which commensally live in the human oral system. In the current study, the impacts of L. plantarum on maintaining oral system health were investigated, and the molecular mechanisms of inhibition of oral cancer KB cells mediated by L. plantarum were evaluated using real-time polymerase chain reaction (PCR) and FACS flow cytometry analyses. Results: Our findings showed that L. plantarum is effective in the signal transduction of the oral cancer cells through upregulation and downregulation of PTEN and MAPK pathways, respectively. Conclusion: Based on the biological effects of oral candidate probiotics candidate bacterium L. plantarum on functional expression of PTEN and MAPK pathways, this microorganism seems to play a key role in controlling undesired cancer development in the oral system. Taken all, L. plantarum is proposed as a potential candidate for probiotics cancer therapy.

The immunomodulatory activity of secondary metabolites isolated from Streptomyces calvus on human peripheral blood mononuclear cells.

BACKGROUND: The natural products derived from micro-organisms are potential candidates for the discovery of novel drugs. Streptomyces bacteria are prolific sources of secondary metabolites with a wide variety of biological activities. Streptomyces calvus (S. calvus) is one strain of this genus and may be an appropriate candidate for isolating new compounds. In this study, the immunomodulatory effects of S. calvus secondary metabolites on the expression of various cytokine genes by human peripheral blood mononuclear cells (PBMCs) were evaluated. METHODS: A bacterial sample was inoculated in Mueller Hinton Broth and secondary metabolites were extracted. PBMCs were isolated from venous blood and were treated with S. calvus secondary metabolites for 48 h. The cell proliferation was assessed by Methyl tetrazolium bromide (MTT) assay and quantitative real-time polymerase chain reaction (qRT-PCR) assays to survey mRNA expressions of selected pro-inflammatory and inhibitory cytokine genes. RESULTS: Secondary metabolites augmented interleukin-2 and interferon-γ gene expression in PBMCs at low doses and also reduced the levels of immunosuppressive cytokine interleukin-10. In addition, the proliferation of PBMCs substantially increased in response to metabolite treatment in a concentration-dependent manner (p < 0.001). CONCLUSION: This in vitro study revealed that the secondary metabolites from S. calvus can successfully stimulate human PBMCs. Therefore, these metabolites have the potential to serve as robust immunomodulators.

Green Synthesis of Gold Nanoparticles by a Metal Resistant Arthrobacter nitroguajacolicus Isolated From Gold Mine.

Biosynthesis of gold nanoparticles would benefit from the development of clean, nontoxic and environmentally acceptable procedures concerning microorganisms from bacteria to fungi and even algae. Actinobacteria are soil bacteria which have the enormous ability as biotechnological tools. In this paper, we reported the biosynthesis of gold nanoparticles by a member of Arthrobacter genus isolated from Andaliyan gold mine in north-west of Iran. This metal resistance strain obtained from an acidophilic region ( ~ pH 5.6). The UV-vis and XRD spectra of the aqueous medium containing the strain and 1 mM HAuCl 4 for 24 h, demonstrated the formation of gold nanoparticles. TEM micrographs showed intra-extracellular production of gold nanoparticles with spherical shape and average size of 40 nm. The result of morphological and molecular tests revealed that the isolate was belonged to Atrhrobacter and has 100% similarity in 16SrRNA gene sequences to Arthrobacter nitroguajacolicus.

Isolation and Molecular Identification of Streptomyces spp. with Antibacterial Activity from Northwest of Iran.

INTRODUCTION: Streptomyces are a group of prokaryotes that are usually found in all types of ecosystems including water and soil. This group of bacteria is noteworthy as antibiotic producers; so the isolation and characterization of new species seemed to be crucial in introduction of markedly favorable antibiotics. Therefore, in this study we aim to isolate and characterize novel strains of Streptomyces with high antibiotic production capability. METHODS: To achieve this goal, from 140 isolates collected throughout northwest of Iran, 12 selected Streptomyces isolates which exhibited high antibacterial activity against pathogenic bacteria were subjected to PCR reaction for identification via 16S rDNA gene and random amplified polymorphic DNA (RAPD) pattern analysis. RESULTS: Analysis of morphological and biochemical characteristics and the 16S rDNA gene sequence indicated that all 12 selected isolates belonged to the genus Streptomyces. Moreover, screening of the isolates with regard to their antimicrobial activity against indicator bacteria as well as their classification using RAPD analysis revealed that G614C1 and K36C5 isolates have considerable antimicrobial activity and high similarity to Streptomyces coelicolor and Sreptomyces albogriseolus, respectively. CONCLUSION: Since many isolates in this study showed inhibitory effects against pathogenic bacteria, soil of northwest of Iran could be used as a rich source to be explored for novel Streptomyces strains with high potency of antibiotic production.

Identification and characterization of a Streptomyces sp. isolate exhibiting activity against multidrug-resistant coagulase-negative Staphylococci.

The resistance of 220 coagulase-negative Staphylococci (CNS) (associated with animal disease) to 13 antibiotics were determined using the disk diffusion method. 35.9% of multidrug-resistant coagulase-negative Staphylococci (MR-CNS) exhibited resistance to five or more than five antibiotics; all of these bacteria were resistant to methicillin too. The new Streptomyces sp. ABRIINW111 was isolated from the Zagros Mountains Hamadan, Iran. The 16S rDNA sequence of the isolate indicated that it has 98% similarity to S. levis, but some mutations in the alpha and gamma regions of the 16S rDNA sequence emphasize the probability of the existence of a new species. Preliminary and secondary antibacterial screenings revealed that the isolate is active against gram negative and positive bacteria. The diethyl ether extracted metabolite of the Streptomyces sp. ABRIINW111 showed an effective antibacterial activity against MR-CNS. So the diethyl ether extract of the new Streptomyces sp. strain ABRIINW111 can inhibit the MR-CNS in vitro, and it can offer a new approach to treat MR-CNS infectious patients.