Photoinactivation Effects of Curcumin, Nano-curcumin, and Erythrosine on Planktonic and Biofilm Cultures of Streptococcus mutans

Introduction: This in vitro study was conducted to assess the phototoxic effects of curcumin, nano-curcumin, and erythrosine on the viability of Streptococcus mutans (S. mutans) in suspension and biofilm forms. Methods: Various concentrations of curcumin (1.5 g/L, 3 g/L), nano-curcumin (3 g/L), and erythrosine (100 μM/L, 250 μM/L) were examined for their impact on planktonic and biofilm cultures of S. mutans, either individually or in conjunction with light irradiation (photodynamic therapy or PDT). A blue light-emitting diode (LED) with a central wavelength of 450 nm served as the light source. The results were compared to 0.12% chlorhexidine digluconate (CHX) as the positive control, and a solution containing neither a photosensitizer (PS) nor a light source as the negative control group. The dependent variable was the number of viable microorganisms per experiment (CFU/mL). Results: Antimicrobial PDT caused a significant reduction in the viability of S. mutans in both planktonic and biofilm forms, compared to the negative control group (P<0.05). The highest cell killing was observed in PDT groups with curcumin 3 g/L or erythrosine 250 μmol/L, although the difference with PDT groups using curcumin 1.5 g/L or erythrosine 100 μmol/L was not significant (P>0.05). Antimicrobial treatments were more effective against planktonic S. mutans than the biofilm form. Conclusion: PDT with either curcumin 1.5 g/L or erythrosine 100 μmol/L may be suggested as an alternative to CHX to inactivate the bacteria in dental plaque or deep cavities. Nano-curcumin, at the selected concentration, exhibited lower efficacy in killing S. mutans compared to Curcumin or erythrosine.

Production and Evaluation of Ag85B:HspX:hFcγ1 Immunogenicity as an Fc Fusion Recombinant Multi-Stage Vaccine Candidate Against Mycobacterium tuberculosis

An urgent need is to introduce an effective vaccine against Mycobacterium tuberculosis (M.tb) infection. In the present study, a multi-stage M.tb immunodominant Fcγ1 fusion protein (Ag85B:HspX:hFcγ1) was designed and produced, and the immunogenicity of purified protein was evaluated. This recombinant fusion protein was produced in the Pichia pastoris expression system. The HiTrap-rPA column affinity chromatography purified and confirmed the fusion protein using ELISA and Western blotting methods. The co-localisation assay was used to confirm its proper folding and function. IFN-γ, IL-12, IL-4, and TGF-β expression in C57BL/6 mice then evaluated the immunogenicity of the construct in the presence and absence of BCG. After expression optimisation, medium-scale production and the Western blotting test confirmed suitable production of Ag85B:HspX:hFcγ1. The co-localisation results on antigen-presenting cells (APCs) showed that Ag85B:HspX:hFcγ1 properly folded and bound to hFcγRI. This strong co-localisation with its receptor can confirm inducing proper Th1 responses. The in vivo immunisation assay showed no difference in the expression of IL-4 but a substantial increase in the expression of IFN-γ and IL-12 (P ≤ 0.02) and a moderate increase in TGF-β (P = 0.05). In vivo immunisation assay revealed that Th1-inducing pathways have been stimulated, as IFN-γ and IL-12 strongly, and TGF-β expression moderately increased in Ag85B:HspX:hFcγ1 group and Ag85B:HspX:hFcγ1+BCG. Furthermore, the production of IFN-γ from splenocytes in the Ag85B:HspX:hFcγ1 group was enormously higher than in other treatments. Therefore, this Fc fusion protein can make a selective multi-stage delivery system for inducing appropriate Th1 responses and is used as a subunit vaccine alone or in combination with others.

Sustain-release lipid-liquid crystal formulations of pexiganan against Helicobacter pylori infection: in vitro evaluation in C57BL/6 mice

INTRODUCTION

The Gram-negative bacterium Helicobacter pylori, H. pylori, is associated with significant digestive disorders. However, the effectiveness of bacterial eradication is declining due to drug resistance. A potent anti-H. pylori activity is shown by the natural antimicrobial peptide pexiganan.

OBJECTIVE

The current study aimed to evaluate the effectiveness of pexiganan and its lipid-liquid crystals (LLCs) in inducing Helicobacter pylori in mice.

METHODS

In this experimental study, H. pylori infection was first induced in C57BL/6 mice. Secondly, the antibacterial efficacy of pexiganan and its LLCs formulations was investigated to eliminate H. pylori infection.

RESULTS

The H. pylori infection could not be completely eradicated by pexiganan peptide alone. However, incorporating pexiganan within the LLC formulation resulted in an increased elimination of H. pylori. Under the H&E strain, the pexiganan-LLCs formulation revealed minimal mucosal alterations and a lower amount of inflammatory cell infiltration in the stomach compared to the placebo.

CONCLUSION

Clarithromycin was more effective than pexiganan at all tested concentrations. Furthermore, the pexiganan-loaded LLCs exhibited superior efficacy in curing H. pylori infection in a mouse model compared to pexiganan alone. This formulation can enhance H. pylori clearance while mitigating the adverse effects, typically associated with conventional drugs, leading to a viable alternative to current treatment options.

Effects of probiotic yogurt, casein phosphopeptide-amorphous calcium phosphate, and xylitol chewing gums on the salivary count of Streptococcus mutans: A single-blinded randomized controlled clinical trial

Background

Dental caries is a preventable multifactorial disease, with Streptococcus mutans being suggested to be its primary pathogen. Our study aim was to compare the effects of three different low-cost and easy-to-use regimens with that of the gold standard (chlorhexidine [CHX] mouthwash) on the count of salivary S. mutans in dental students over 30 days.

Materials and Methods

In this single-blinded parallel randomized controlled clinical trial, a total of 120 dental students were included and randomly allocated into four intervention groups: (1) CHX mouthwash (control(, (2) probiotic yogurt, (3) casein phosphopeptide-amorphous calcium phosphate chewing gum, and (4) xylitol chewing gum. Salivary S. mutans counts were evaluated at baseline, 15 days, and 30 days after initiation of the study and compared at different times and among different groups using the repeated measures analysis of variance design analysis and least significant difference test with SPSS software version 20. The level of significance was determined to be 0.05.

Results

The microorganism count variable at baseline, first, and second follow-ups was significantly different for all groups except the probiotic yogurt group (P = 0.340). S. mutans count was significantly different when comparing the first follow-up and baseline values in the CHX and xylitol gum groups (P = 0.027, P = 0.037). When comparing the second follow-up with baseline values, a significant difference was observed in the xylitol gum group (P = 0.003).

Conclusion

Xylitol chewing gum seems to be a viable alternative to the gold standard (CHX mouthwash) in reducing the salivary count of S. mutans.

Antimicrobial photodynamic therapy against Lactobacillus casei using curcumin, nano-curcumin, or erythrosine and a dental LED curing device

This study aimed to investigate the photodynamic effects of curcumin, nanomicelle curcumin, and erythrosine on Lactobacillus casei (L. casei). Various concentrations of curcumin (1.5 g/L, 3 g/L), nano-curcumin (3 g/L), and erythrosine (100 µM/L, 250 µM/L) were tested either alone or combined with light irradiation (PDT effect) against L. casei in planktonic and biofilm cultures. The light was emitted from a light-emitting diode (LED) with a central wavelength of 450 nm. A 0.12% chlorhexidine digluconate (CHX) solution served as the positive control, and a solution containing neither photosensitizer nor light was the negative control group. The number of viable microorganisms was determined using serial dilution. There was a significant difference in the viability of L. casei in both planktonic and biofilm forms (P < 0.05). In the planktonic culture, the antibacterial effects of CHX and PDT groups with curcumin 3 g/L and erythrosine 250 µM/L were significantly greater than the other groups (P < 0.05). For L. casei biofilms, the greatest toxic effects were observed in CHX and PDT groups with curcumin 3 g/L, erythrosine 250 µmol/L, erythrosine 100 µmol/L, and nanomicelle curcumin 3 g/L, with a significant difference to other groups (P < 0.05). The antibacterial effects of all photosensitizers (except erythrosine 250 µmol/L at planktonic culture) enhanced significantly when combined with light irradiation (P < 0.05). PDT with curcumin 3 g/L or erythrosine 250 µmol/L produced comparable results to CHX against L. casei at both planktonic and biofilm cultures. Alternatively, PDT with erythrosine 100 µmol/L or nanomicelle curcumin 3 g/L could be suggested to kill L. casei biofilms.

Novel approaches to overcome Colistin resistance in Acinetobacter baumannii: Exploring quorum quenching as a potential solution

Acinetobacter baumannii is responsible for a variety of infections, such as nosocomial infections. In recent years, this pathogen has gained resistance to many antibiotics, and thus, carbapenems were used to treat infections with MDR A. baumannii strains in clinical settings. However, as carbapenem-resistant isolates are becoming increasingly prevalent, Colistin is now used as the last line of defense against resistant A. baumannii strains. Unfortunately, reports are increasing on the presence of Colistin-resistant phenotypes in infections caused by A. baumannii, creating an urgent need to find a substitute way to combat these resistant isolates. Quorum sensing inhibition, also known as quorum quenching, is an efficient alternative way of reversing resistance in different Gram-negative bacteria. Quorum sensing is a mechanism used by bacteria to communicate with each other by secreting signal molecules. When the population of bacteria increases and the concentration of signal molecules reaches a certain threshold, bacteria can implement mechanisms to adapt to a hostile environment, such as biofilm formation. Biofilms have many advantages for pathogens, such as antibiotic resistance. Different studies have revealed that disrupting the biofilm of A. baumannii makes it more susceptible to antibiotics. Although very few studies have been conducted on the biofilm disruption through quorum quenching in Colistin-resistant A. baumannii, these studies and similar studies bring hope in finding an alternative way of treating the Colistin-resistant isolates. In conclusion, quorum quenching has the potential to be used against Colistin-resistant A. baumannii.

Characterization of carbapenem-resistant Escherichia coli and Klebsiella: a role for AmpC-producing isolates

Aim: This study aimed to investigate the role of AmpC enzymes in carbapenem resistance among AmpC/extended-spectrum β-lactamase (ESBL)-producing clinical isolates of Escherichia coli and Klebsiella spp. Methods: Fifty-six bacterial strains that were AmpC producers were examined. The antibiotic susceptibility test was performed by the disk diffusion and E-test. The prevalence of the plasmid carbapenemase was determined using PCR. Results: The resistance to meropenem in the AmpC⁺/ESBL⁺ group was 64%, higher than that reported for the AmpC^-/ESBL⁺ group. Ten isolates of the carbapenem-resistant AmpC producers were negative for carbapenemase-encoding genes. Conclusion: Carbapenem resistance among AmpC-producing isolates with negative results for carbapenemase-encoding genes potentially demonstrates the role of AmpC enzymes among these isolates.

Genotyping of Mycobacterium tuberculosis complex isolated from humans and animals in northeastern Iran

The objective of this study was to genotype Mycobacterium tuberculosis complex isolated from humans and cattle in northern Iran. Over the course of one year, a total of 120 human and 21 cattle isolates were tested using region of difference (RD)-based polymerase chain reaction (PCR) and mycobacterial interspersed repetitive unites-variable number tandem repeats (MIRU-VNTR). In M. tuberculosis, out of 120 isolates investigated, the most common genotype detected was NEW-1 (53.3%), followed by CAS/ Delhi (24.1%), Haarlem (5%), Beijing (4.16%), Uganda I (4.16%), S (3.3%), Ural (0.83%), TUR (0.83%), Uganda II (0.83%), Lam (0.83%) and Cameroon (0.83%). The HGDI rate was 0.9981 and the clustering rate was 10.83. Of the isolates, QUB26 had the highest allele diversity (h: 0.76), while the loci Mtub29 and MIRU24 had the lowest (h: 0). In M. Bovis, out of 123 collected tissue samples, 21 (17%) grew on culture media. The HGDI rate was 0.71 and clustering rate was 85.7%. The locus ETRC had the highest allele diversity (h: 0.45). The findings of this study suggest that there is high genetic diversity among M. tuberculosis isolates in Khorasan Razavi Province, which is consistent with similar results from other studies in other provinces in Iran and neighboring countries. This indicates that the prevalent genotypes in this study are spreading in the Middle East region. Furthermore, considering that M. Bovis isolates were identified in two clusters, it seems that all of them have a common origin and are circulating among the livestock farms in the province.

Gene Expression Study of Host and Mycobacterium tuberculosis Interactions in the Manifestation of Acute Tuberculosis

Mycobacterium tuberculosis (M.tb) could induce type IV hypersensitivity. The chemotaxis of the leukocytes toward the site of infection and producing matrix metalloproteinases (MMPs) are key factors in the immune pathogenesis of tuberculosis (TB). Mononuclear cells were isolated from bronchoalveolar lavage (BAL) specimens, and the target from genomic DNA was used for qPCR TB diagnosis and cDNA for specific RT-qPCR gene expression. The subjects were then classified into TB⁺ and TB^- groups, and the expression levels of CFP-10, ESAT-6, CCR1, CCR12 and MMP3,9 were evaluated. The mean level of CCR1 expression in TB⁺ and TB^- patients' BAL was 1.71 ± 0.78 and 0.5 ± 0.22, respectively, which was statistically different (p = 0.01). The CCR2 level, in TB⁺ (2.07 ± 1.4), was higher than in TB^- patients (1.42 ± 0.89, p = 0.01). The MMP9 expression in TB⁺ was 2.56 ± 0.68, also higher than in TB^- patients (1.13 ± 0.35), while MMP3 was lower in TB⁺ (0.22 ± 0.09) than in TB^- (0.64 ± 0.230, p = 0.05). The CCR2/CCR1 and MMP3/MMP9 balance in TB⁺ were reduced, compared to the TB^-. The CFP-10 and ESAT-6 were highly expressed in TB⁺ patients. The CFP-10 expression had a strong negative correlation with albumin (r =  - 0.93, p = 0.001), and a negative correlation with neutrophil (r =  - 0.444, p = 0.1 with 90% CI). The MMP-9 expression showed a positive correlation with WBC count (r = 0.61, p = 0.02), in TB⁺, and had a negative correlation with BMI (r = 0.59, p = 0.02) in TB^-. The M.tb CFP-10 might be implicated in lowering CCR2 and MMP3 expression in favour of M.tb dissemination. Moreover, the balance of CCR2/CCR1 and MMP3/MMP9 can be used as prognostic factors in the severity of TB.

Mucosal and systemic immunization against tuberculosis by ISCOMATRIX nano adjuvant co-administered with alginate coated chitosan nanoparticles

Objectives

BCG vaccine has no longer been appreciated to immunize against tuberculosis, worldwide, so novel appropriate adjuvants have been dedicated to improve immune responses. This study aimed to evaluate the immunomodulatory effects of ISCOMATRIX as an adjuvant to stimulate potent humoral and cellular immune responses of the PPE17 loaded alginate coated nanoparticles through subcutaneous and intranasal vaccination.

Materials and Methods

Size, polydispersity index, and morphology of the resulting colloidal particles were explored by dynamic light scattering (DLS). The cellular and/or humoral immune stimulation properties of ISCOMATRIX adjuvant were measured by measuring the level of IFNγ, IL-4, IL-17, and TGFβ in spleen cell cultures and IgG1 and IgG2a in serum and sIgA in nasal lavage of immunized mice, respectively.

Results

The spherical cage-like particles of ISCOMATRIX adjuvant have optimal size of 59±6 nm appropriate for an immune adjuvant vaccine. ISCOMATRIX induced robust Th1 (IFN-γ) and IL-17 cytokine response also significant IgG2a and IgG1antibodies in both subcutaneous and intranasal routes and elicited mucosal sIgA response when administered intranasally. As a booster for BCG, ISCOMATRIX induced immune responses only in subcutaneous route.

Conclusion

These findings indicate that ISCOMATRIX is a promising adjuvant with the potential for increasing cellular and humoral immunity both after subcutaneous and intranasal administration.

Anticancer activity of Pseudomonas aeruginosa derived peptide with iRGD in colon cancer therapy

Objectives

Colon cancer is well-known as a life-threatening disease. Since the current treatment modalities for this type of cancer are powerful yet face some limitations, finding novel treatments is required to achieve better outcomes with fewer side effects. Here we investigated the therapeutic potential of Azurin-p28 alone or along with iRGD (Ac-CRGDKGPDC-amide) as a tumor-penetrating peptide and 5-fluorouracil (5-FU) for colon cancer.

Materials and Methods

Inhibitory effect of p28 with or without iRGD/5-FU was studied in CT26 and HT29, as well as the xenograft animal model of cancer. The effect of p28 alone or along with iRGD/5-FU on cell migration, apoptotic activity, and cell cycle of the cell lines was assessed. Level of the BAX and BCL2 genes, tumor suppressor genes [(p53 and collagen type-Iα1 (COL1A1), collagen type-Iα2 (COL1A2)] were assessed by quantitative RT-PCR.

Results

These findings show that using p28 with or without iRGD and 5-FU raised the level of p53 and BAX but decreased BCL2, compared with control and 5-FU groups in tissues of the tumor, which result in raising the apoptosis.

Conclusion

It seems that p28 may be used as a new therapeutic approach in colon cancer therapy that can enhance the anti-tumor effect of 5-FU.

Antimicrobial peptides: natural or synthetic defense peptides against HBV and HCV infections

According to the literature, treatment of HCV and HBV infections faces challenges due to problems such as the emergence of drug-resistant mutants, the high cost of treatment, and the side effects of current antiviral therapy. Antimicrobial peptides (AMPs), a group of small peptides, are a part of the immune system and are considered as an alternative treatment for microbial infections. These peptides are water-soluble with amphiphilic (hydrophilic and hydrophobic surfaces) characteristics. AMPs are produced by a wide range of organisms including both prokaryotic and eukaryotic cells. The antiviral mechanisms of AMPs include inhibiting virus entry, inhibiting intracellular virus replication, inhibiting intracellular viral packaging, and inducing immune responses. In addition, AMPs are a new generation of antiviral biomolecules that have very low toxicity for human host cells, particularly liver cell lines. AMPs can be considered as one of the most important strategies for developing new adjuvant drugs in the treatment of HBV and HCV infections. In the present study, several groups of AMPs (with a net positive charge) such as Human cathelicidin, Claudin-1, Defensins, Hepcidin, Lactoferrin, Casein, Plectasin, Micrococcin P1, Scorpion venom, and Synthetic peptides were reviewed with antiviral properties against HBV and HCV.

Evaluation of Mutations Related to Streptomycin Resistance in Mycobacterium tuberculosis Clinical Isolates

Drug resistance to streptomycin in the clinical isolates of Mycobacterium tuberculosis (MTB) needs special consideration. It can mostly be caused by mutations in four genes with the names rpsL, rrs, gidB, and whiB7. The main objective of this study was the evaluation of the type and frequency of mutations in these mentioned genes using the PCR-sequencing method. This study was performed on 15 streptomycin-resistant and five streptomycin-sensitive isolates. Among resistant isolates, 11 samples contained mutations in codon 43 of the rpsL gene, which caused the lysine to be converted to arginine. Additionally, all of the isolates had mutations in the gidB. Missense mutations in codons 92 and 20 of this gene result in the amino acids Glutamic acid or Arginine being changed to Aspartic acid or Proline, respectively. No mutations in the rrs or whiB7 were found in any of the samples. Simultaneous mutations of rpsL and gidB were found in 10 isolates, the majority of which were Beijing strain. The results showed that the mutations of rpsL and gidB genes are mostly responsible for the streptomycin resistance in the evaluated MTB isolates. Furthermore, the discovery of dual mutations in Beijing strains highlights the strain's considerable potential for developing Tuberculosis drug resistance.

Bacterial Peptides and Bacteriocins as a Promising Therapy for Solid Tumor

The conventional treatment is faced with limitations in treating solid tumors due to their specific pathophysiology. Several novel therapeutics have been introduced in recent decades to treat solid tumors. Among these new methods, tumor therapy using bacterial products like bacteriocins and peptides has been of great interest due to their unique characteristics and advantages of them in comparison to the conventional treatment, including that they can precisely target tumor cells, selective toxicity for tumor cells, low side effect on normal cells, toxicity activity for MDR cancer cells, used as the target delivery vehicles and enhancing drug delivery. Moreover, their small size and low molecular weight have made them easy to synthesize and modify. Furthermore, in recent years, genetic engineering has expanded the therapeutic ability of peptides to treat solid tumors, which results in overcoming the peptide drawbacks. The present review mainly focuses on the new advances in applying bacterial peptides and bacteriocins in treating human solid tumors.

Assessment of antibiotic resistance changes during the Covid-19 pandemic in northeast of Iran during 2020-2022: an epidemiological study

Background

The coronavirus disease 2019 seems to change antibiotic resistance pattern. Certain conditions in the Covid-19 era may be contributing to the rise of antimicrobial resistance (AMR). Due to the limited information on the impact of Covid-19 on antimicrobial resistance (AMR), the purpose of this research was to investigate the trend in antimicrobial resistance changes of E. coli, P. aeruginosa, K. pneumoniae, and A. baumannii in Hasheminezhad hospital. This hospital was a Corona center in Mashhad at the onset of this epidemic.

Methods

1672 clinical samples were collected between January 21, 2020 and January 30, 2022from patients hospitalized at Hasheminezhad Hospital in Mashhad, Conventional microbiological procedures for identifying gram-negative bacteria and antibiotic susceptibility testing were used, according to the clinical and laboratory standards institute (CLSI) 2021. The two years of the pandemic, from the initial stage of the outbreak until the 6th peak, (January 2020 to and January 2022) were divided into 9 periods according to the seasons.

Results

Highest resistance rates were seen in E. coli (615 samples), K. pneumoniae (351 samples), P. aeruginosa (362 samples) and A. baumannii (344 samples) to Ampicillin (89.6%), Ampicillin (98%), Imipenem (91.8%), and Ceftazidime (94.6%), respectively. The largest change in antibiotic resistance was seen between Summer 2020 and Summer 2021 for K. pneumoniae with about a 30% rise in antibiotic resistance to Ceftriaxone.

Conclusions

All 4 species evaluated in this study, have shown rising AMR rates during the first year of the pandemic in the northeast of Iran. This study revealed that E. coli, P. aeruginosa, K. pneumoniae, and A. baumannii strains in Northern Iran have a higher level of antibiotic resistance than what was measured in similar studies conducted before the pandemic. This will further restrict treatment choices and jeopardize global public health.

PCR-Based Diagnosis of Leishmania Species in Chronic Granulomatous Dermatitis in Mashhad, Iran

Background

Cutaneous leishmaniasis (CL) is a chronic granulomatous dermatitis (CGD). Approximately, 90% of CL patients are from seven countries including Iran. We explain polymerase chain reaction (PCR) diagnostic technique for chronic granulomatosis dermatoses including CL in Mashhad, Iran.

Methods

This study enrolled 64 patients within 2009-2013 with chronic granulomatosis dermatitis referred to dermatology and pathology departments of Imam Reza Hospital, affiliated to Mashhad University of Medical Sciences (MUMS), Mashhad, Iran. We gathered demographic data from archived folders. Histological light microscopic evaluation and parasitological tests were done on selected specimens. We used PCR diagnostic test on specimens. Statistical analysis was done by SPSS version 15.

Results

Generally, 7 out of 64 specimens had Leishmania DNA and other samples had no Leishmania DNA. The mean age of patients was 46 ± 18.77 years; disease duration was 7 ± 6.73 months ranging from 1-24 months. Most of the lesions were located on face and upper limb. Totally, 5 out of 7 samples were Leishmania major and 2 out of 7 samples were L. tropica. Tuberculoid granuloma was present in L. tropica samples and 3 of L. major samples. Other light microscopic changes were as follow: 42 suppurative granuloma, and epidermal changes including atrophy, pseudoepitheliomatous hyperplasia, and parakeratosis with dermal changes including, plasma cell, involvement of papillary and reticular dermis, and distribution of granuloma to hypodermis.

Conclusion

Our results addressed PCR-based diagnosis of chronic cutaneous leishmaniasis, which is resulted from L. major and L. tropica.

Effects of Magnesium Oxide Nanoparticles Incorporation on Shear Bond Strength and Antibacterial Activity of an Orthodontic Composite: An In Vitro Study

This study aimed to evaluate the effects of magnesium oxide (MgO) nanoparticle (NP) incorporation on shear bond strength (SBS) and antibacterial property of orthodontic composites. A total of 100 mounted premolar teeth were randomly divided into five groups. In group 1 (control), the brackets were bonded to the teeth using the GC Ortho Connect orthodontic composite, while the brackets of groups 2 to 5 were bonded by the GC Ortho Connect orthodontic composite that contained 0.5%, 1%, 2%, and 4% weight percentages (w/w) of MgO NPs, respectively and then the SBS was measured. In the following, we evaluated the antibacterial properties of the MgO NP-containing composite on Streptococcus mutans (S. mutans) bacteria by the direct contact test method. According to results, there were no significant changes in the SBS as the MgO NP concentration was increased up to 1%, while the SBSs of the 2% and 4% MgO NPs were decreased when compared to the other three groups. The outcomes of the direct contact test indicated the case of 1% as being the minimum ratio of MgO NPs, which almost caused the entire annihilation of the S. mutans bacteria. In conclusion, the orthodontic composite containing 1% MgO NPs can display a significant antibacterial effect against S. mutans bacteria without inducing any negative effect on the SBS.

Conceptual framework of antibiotic stewardship programs in reducing ESBL-producing Enterobacteriaceae: a systematic review and meta-analysis

Today, the phenomenon of antibiotic resistance has become one of the main concerns of health system around the world. Antimicrobial stewardship programs (ASPs) are considered as the most important strategy in optimizing antibiotic consumption, which in turn reduce the emergence of multidrug/extensively drug-resistant (MDR/XDR) microorganisms, as well as reducing mortality and healthcare costs. However, the effectiveness of APSs in controlling the spread of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae has not been investigated. The pooled odds ratio for the effectiveness of ASPs in reducing ESBL-producing Enterobacteriaceae was 0.82 (95% CI: 0.70-0.98; P value: 0.03); our results showed that in group with implemented ASPs, the prevalence of infection associated with these bacteria had been reduced by 11.8%. Overall, antimicrobial stewardship strategies are significantly effective in reducing ESBL-producing Enterobacteriaceae infections. The present study concluded that a comprehensive stewardship program will certainly reduce the mortality rate, as well as hospitalization stay and treatment costs. In general, our findings strongly support the performance of ASPs in healthcare centers.

Evaluation of phenotypic and genotypic patterns of aminoglycoside resistance in the Gram-negative bacteria isolates collected from pediatric and general hospitals

The purpose of the current study was to evaluate the phenotypic and genotypic patterns of aminoglycoside resistance among the Gram-negative bacteria (GNB) isolates collected from pediatric and general hospitals in Iran. A total of 836 clinical isolates of GNB were collected from pediatric and general hospitals from January 2018 to the end of December 2019. The identification of bacterial isolates was performed by conventional biochemical tests. Susceptibility to aminoglycosides was evaluated by the disk diffusion method (DDM). The frequency of genes encoding aminoglycoside-modifying enzymes (AMEs) was screened by the PCR method via specific primers. Among all pediatric and general hospitals, the predominant GNB isolates were Acinetobacter spp. (n = 327) and Escherichia coli (n = 144). However, E. coli (n = 20/144; 13.9%) had the highest frequency in clinical samples collected from pediatrics. The DDM results showed that 64.3% of all GNB were resistant to all of the tested aminoglycoside agents. Acinetobacter spp. and Klebsiella pneumoniae with 93.6%, Pseudomonas aeruginosa with 93.4%, and Enterobacter spp. with 86.5% exhibited very high levels of resistance to gentamicin. Amikacin was the most effective antibiotic against E. coli isolates. In total, the results showed that the aac (6')-Ib gene with 59% had the highest frequency among genes encoding AMEs in GNB. The frequency of the surveyed aminoglycoside-modifying enzyme genes among all GNB was found as follows: aph (3')-VIe (48.7%), aadA15 (38.6%), aph (3')-Ia (31.3%), aph (3')-II (14.4%), and aph (6) (2.6%). The obtained data demonstrated that the phenotypic and genotypic aminoglycoside resistance among GNB was quite high and it is possible that the resistance genes may frequently spread among clinical isolates of GNB.

Green synthesis of selenium nanoparticles using Rosmarinus officinalis and investigated their antimicrobial activity

The interest of many has been attracted by plant-mediated synthesizing procedures for nanoparticles since they provide certain qualities including being cost-effective, quick, and compatible with the environment. In this regard, this work introduces the production of selenium-nanoparticles (Se-NPs) in a biological manner utilizing aqueous extracts of Rosmarinus officinalis (R. officinalis). Production of Se-NPs was confirmed using UV-visible (UV-Vis) spectrophotometry. Also, dynamic light scattering (DLS) analysis was used for determination particle size distribution, while we distinguished the identification of crystalline construction of nanoparticles through the means of X-ray diffraction (XRD) pattern, DLS, and transmission electron microscopy (TEM) examination indicated that Se-NPs are often spherical with a size about 20 to 40 nm. The minimum inhibitory concentration (MIC) of the synthesized Se-NPs by R. officinalis extract against Mycobacterium tuberculosis (M. tuberculosis), Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Escherichia coli (E. coli), and Pseudomonas aeruginosa (P. aeruginosa) was 256, 16, 32, 128, and 64 µg/mL, respectively. The synthesized Se-NPs had no significant effect on Mycobacterium simiae (M. simiae) and had exhibited a strong antimicrobial functionality towards the gram-positive and gram-negative bacteria and can stand as a potent antibacterial agent.

Levofloxacin-based therapy as an efficient alternative for eradicating Helicobacter pylori infection in Iran: a systematic review and meta-analysis

OBJECTIVES

Despite excessive resistance of Helicobacter pylori to clarithromycin among Iranian population, unfortunately, clarithromycin-based therapy is still prescribed in Iran. Recent studies have shown high rates of H. pylori eradication in patients treated with levofloxacin. The main purpose of this study was to compare the effect of levofloxacin with clarithromycin on the eradication of H. pylori infection in Iranian population.

METHODS

A comprehensive meta-analysis was done for the relevant cohort studies and clinical trials to compare the therapeutic effects of levofloxacin with clarithromycin in Iranian population. We pooled the data using odds ratio corresponding to 95% confidence intervals to find the clinical efficacy of levofloxacin versus clarithromycin to treat H. pylori infection. The heterogeneity and publication bias were also measured for the included studies.

RESULTS

A total of 13 studies were included in the quantitative synthesis. Eradication rate in patients receiving levofloxacin and clarithromycin were 75% and 66.3%, respectively (OR: 1.76; 95% CI: 1.40-2.20). In addition, in the subgroup analysis, it was confirmed that cure rate is relatively higher in levofloxacin-treated cases. However, there is significant heterogeneity as well as publication bias, thus, the results need to be interpreted with caution.

CONCLUSIONS

We found that the success of levofloxacin treatment was significantly higher than that of clarithromycin. Therefore, it is suggested that clarithromycin-based triple therapy be replaced by levofloxacin-based triple therapy in countries with high resistance rate to clarithromycin such as Iran. Nevertheless, findings of the present study need to be approved with larger investigation on Iranian population.

Game theory applications in host-microbe interactions toward disease manifestation: Mycobacterium tuberculosis infection as an example

OBJECTIVES

Game theory describes the interactions between two players and the pay-off from winning, losing, or compromising. In the present study, Mycobacterium tuberculosis (Mtb)-host interactions were used as an example for the application of game theory to describe and predict the different outcomes of Mtb-infection and introducing target molecules for use in protection or therapy.

MATERIALS AND METHODS

The gene expression for eight main markers (CCR1, CCR2, IDO, Tbet, TGFβ, iNOS, MMP3, MMP9) of host response and three Mtb virulence factors (Ag85B, CFP-10, ESAT-6) were assessed in broncho-alveolar lavage of TB⁺ and TB^- patients.

RESULTS

The players' strategies in the "Nash equilibrium", showed that Ag85B is the main virulence factor for Mtb in active phase, and also the most immunogenic factor, if the host can respond by high expression of T-bet and iNOS toward a Th1 response. In this situation, Mtb can express high levels of ESAT-6 and CFP10 and change the game to the latency, in which host responses by medium expression of T-bet and iNOS and medium level of TGF-β and IDO. Consistently, the IDO expression was 134-times higher in TB⁺s than the TB^-s,and the T-bet expression,~200-times higher in the TB^-s than the TB⁺s. Furthermore, Mtb-Ag85B had a strong positive association with CCR2, T-bet and iNOS, but had a negative correlation with IDO.

CONCLUSION

Ag85B and maybe ESAT6 (without its suppressive C-terminal) should be considered for making subunit vaccines. And, preventing IDO formation in dendritic cells might be a novel target for immunotherapy of tuberculosis, to reduce the pressure of immune-suppression on Th1 responses.

Mycobacterium tuberculosis typing using Allele-specific oligonucleotide multiplex PCR (ASO-PCR) method

Mycobacterium tuberculosis (M. tuberculosis) genotyping provides valuable information related to the origin and the evolution of the isolates. This study aimed to evaluate the applicability of single-nucleotide polymorphisms (SNPs) technique for lineages identification of M. tuberculosis and compare it with mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) method. The lineages of 162 clinically isolates were evaluated using six pair primers by Multiplex-PCR based on SNPs. Among 162 isolates, 70 (43.2%) isolates were lineage 4, following that 62 (38.3%) and 22 (13.6%) isolates were lineage 3 and 2, respectively. The method could not type 8 (4.9%) isolates. Moreover, we could identify 71 out of 79 unknown isolates resulted from the MIRU-VNTR method. The results showed that the SNP typing method has the potential to determine the lineages of M. tuberculosis as a rapid laboratory screening test.

Association of Chlamydia and Mycoplasma infections with susceptibility to ovarian cancer: A systematic review and meta-analysis

BACKGROUND

Ovarian cancer is one of the most prevalent cancers with a high mortality rate in women. Published studies indicate that inflammation, DNA damage, and pelvic inflammatory disease (PID) are the most important risk factors for ovarian cancer and this could be induced and exacerbated by infectious agents such as Chlamydia trachomatis and Mycoplasma genitalium. The aim of this study was to determine the association between Chlamydia and Mycoplasma infections and the risk of ovarian cancer.

METHODS

We carried out a comprehensive search of PubMed, Scopus, Web of Science, Embase, and Google Scholar without limitation on publication date. All relevant studies which investigatived probable potential connection between Chlamydia and Mycoplasma infection and development of ovarian cancer were included.

RESULTS

Eighteen studies comprising a total of 8207 patients were evaluated in the study and this showed that the frequency of infection with Chlamydia and Mycoplasma among ovarian cancer patients was 32.6 % and 23 %, respectively. The results suggested that Chlamydia trachomatis infection increased the overall risk for ovarian cancer by 1.344 fold (OR: 1.344; 95 %CI: 1.19-1.50). Moreover, infection with Mycoplasma infections showed a week but not significant increased risk of ovarian cancer (OR: 1.12; 95 %CI: 0.86-1.44). However, the test for heterogeneity was significant among these studies.

CONCLUSION

This study confirmed the clinical relevance of Chlamydia and Mycoplasma infection and development of the ovarian cancer risk, although the significance was marginal and study heterogeneity was significant. This highlights the need for further studies in this area.

In vitro and in vivo toxicity and antibacterial efficacy of melittin against clinical extensively drug-resistant bacteria

BACKGROUND

Melittin is one of the most studied antimicrobial peptides, and several in vitro experiments have demonstrated its antibacterial efficacy. However, there is evidence showing melittin has non-promising effects such as cytotoxicity and hemolysis. Therefore, concerns about unwanted collateral toxicity of melittin lie ahead in the path toward its clinical development. With these considerations, the present study aimed to fill the gap between in vitro and in vivo studies.

METHODS

In the first step, in vitro toxicity profile of melittin was assessed using cytotoxicity and hemolysis tests. Next, a maximum intraperitoneal (i.p.) sub-lethal dose was determined using BALB/c mice. Besides toxicity, antimicrobial efficacy of melittin against extensively drug-resistant (XDR) Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus (MRSA), and KPC-producing Klebsiella pneumonia (KPC-KP) pathogens were tested using both in vitro and in vivo methods.

RESULTS

Melittin showed extensive hemolysis (HD50 = 0.44 µg/mL), and cytotoxicity (IC50 = 6.45 µg/mL) activities with i.p. LD50 value of 4.98 mg/kg in BALB/c mice. In vitro antimicrobial evaluation showed melittin MIC range from 8 to 32 µg/mL for the studied pathogens. Treatment of infected mice with repeated sub-lethal doses of melittin (2.4 mg/kg) displayed no beneficial effect on their survival and peritoneal bacterial loads.

CONCLUSIONS

These results indicate that melittin at its safe dose could not exhibit antimicrobial activity, which hinders its application in clinical practice.

T helper type 1 biased immune responses by PPE17 loaded core-shell alginate-chitosan nanoparticles after subcutaneous and intranasal administration

PURPOSE

Tuberculosis, a cost and life threatening disease, was being subjected for improving vaccine strategies beyond BCG. Thus, a novel particulate delivery system using alginate-coated chitosan nanoparticles including PPE17 protein and CpG were administered through intranasal (IN) and subcutaneous (SC) routes.

METHODS

The encapsulated nanoparticles were first characterized for size, surface charge, encapsulation efficiency and in vitro release of PPE17 antigen. The nanoparticles were then administered intranasal and subcutaneously to evaluate the induction of systemic and/or mucosal immune responses in mice.

RESULTS

According to our result, the mean size of nanoparticles was measured about 427 nm, and exhibited a negative zeta potential of -37 mV. Following subcutaneous and intranasal administration, the results from cytokines assay showed that an increasing in the level of IFN-γ, and adversely a decrease in the level of IL-4 (presumptive Th1 biased immune response) was happened and also a notable elicitation in IL-17 cytokine was observed.

CONCLUSION

In conclusion, our study demonstrated that alginate-coated chitosan nanoparticles showed to be an effective way to improve BCG efficiency as booster strategy for subcutaneous vaccine, and also can induce strong immune responses as prime strategy through intranasal vaccination.

Practical Methods for Expression of Recombinant Protein in the Pichia pastoris System

One of the most critical challenges of genetic engineering is the expression of recombinant proteins using biological expression systems. Nowadays, different expression systems from bacteria to mammalian tissue culture cells are available for the production of recombinant proteins for medical and industrial purposes. Among various choices, yeast expression systems such as Pichia pastoris are promising candidates. The P. pastoris expression system is a standard tool for the production of biopharmaceuticals and industrial enzymes. It is also considered a unique host for the expression of subunit vaccines which could significantly affect the growing market of medical biotechnology. Using P. pastoris as an expression system for heterologous proteins, this article provides detailed basic protocols for cloning of a recombinant cassette into a suitable expression vector, the transformation of foreign vector DNAs into the yeast by electroporation, and expression and purification of desired recombinant protein. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Cloning of a recombinant cassette into a suitable expression vector Basic Protocol 2: Transformation of P. pastoris and selection of transformants Basic Protocol 3: Optimization and large-scale expression of recombinant proteins Basic Protocol 4: Purification of recombinant proteins.

Anticancer activity of Helicobacter pylori ribosomal protein (HPRP) with iRGD in treatment of colon cancer

PURPOSE

As the conventional therapeutic approaches were not completely successful in the treatment of colon cancer, there is still a need for finding the most efficient therapeutic agents. Here we investigated the anticancer activity of HPRP-A1 that was derived from the N-terminal region of Helicobacter pylori ribosomal protein L1 (RpL1) alone or in combination with tumor-homing peptide iRGD and 5-Fluorouracil (5FU) on colon cancer cell lines (CT26 and HT29) and isograft models of colon cancer.

METHOD

We assessed the tumor growth inhibitory activity of HPRP-A1 with or without iRGD and 5FU on colon cancer in vitro and in vivo. In the in vitro part, we investigate the effect of HPRP-A1 alone and in combination with iRGD/5FU.

RESULTS

Our results demonstrated that co-administration of HPRP-A1 with iRGD increased the apoptosis, while these two peptides in combination with 5FU increased the intracellular level of p53 that upregulate the pro-apoptotic gene BAX and downregulate the anti-apoptotic gene BCL2. HPRP-A1 blocks the cell cycle progression in G0/G1. Co-administration of two peptides significantly reduced the size and weight of the tumors, while the group that received 5FU in combination with the peptides increased the necrotic and decrease the fibrotic area significantly in the tumor tissues, which also disrupt the oxidant/antioxidant balance.

CONCLUSIONS

Our results indicated that HPRP-A1 could be considered an effective agent toward colon cancer in vitro and in vivo with the ability to enhance the effects of conventional chemotherapy agent 5FU.

Molecular typing and prevalence of extended-spectrum β-lactamase genes in diarrhoeagenic Escherichia coli strains isolated from foods and humans in Mashhad, Iran

AIMS

Present study was aimed to determine ESBL-encoding genes distribution in Diarrhoeagenic Escherichia coli (DEC) isolated from animal-source food products and human clinical samples in Mashhad, Iran. The strains were also further studied to analyse genotypic diversity and find genetic relationships between them.

METHODS AND RESULTS

The number of 85 DEC strains including 52 and 33 strains isolated from 300 food and 520 human stool samples, respectively. Randomly amplified polymorphic DNA (RAPD), and repetitive extragenic palindromic-PCR (rep-PCR) typing methods were used to track their genetic relationships. The ESBL-encoding genes prevalence was approximately 70% in both groups of isolates. The bla_TEM , bla_CTX-M and bla_SHV were prevalent in 67·1, 20 and 10·6% of isolates, respectively. The ESBL-positives showed significantly higher resistance rates to gentamicin, co-trimoxazole, tetracycline, aztreonam and chloramphenicol (P < 0·05). Fingerprinting patterns-based dendrograms divided DEC strains into separate clusters irrespective of their sources and pathotypes. In typing field, rep-PCR provided more discriminatory power (Simpson's index of diversity (SID) = 0·925) than RAPD (SID = 0·812).

CONCLUSION

Molecular similarity between certain animal-sourced food products and clinical sample strains supported food-borne transmission routes for genotypic elements such as ESBL-encoding genes.

SIGNIFICANCE AND IMPACT OF THE STUDY

Findings emphasize the importance of resistance issues, the need to improve treatment guidelines and routine surveillance of hygienic measures during food processing.

Prevalence Determination of m. Hominis and m. Genitalium in the Semen Samples in the Northeast of Iran Using Culture and Multiplex Polymerase Chain Reaction

Infertility has recently become a growing social and economic world problem. Genital mycoplasmas, such as Mycoplasma hominis and M. genitalium, are most frequently associated with several adverse effects on men&amp;rsquo;s fertility. The present study aimed to determine the prevalence of M. hominis and M. genitalium in the semen samples in thenortheast of Iran. During thiscross-sectional study from February to May, 2018, 100 semen samples were collected from 100 infertile men in Mashhad, Khorasan Razavi province, northeast of Iran. The presence of M. hominis and M. genitalium was detected by cultivation, polymerase chain reaction (PCR), and Multiplex PCR assays. The colony of mycoplasma was confirmed by Diene&amp;rsquo;s stain; moreover, arginine hydrolysis, glucose, and urea utilization were evaluated. The following semen indices were analyzed according to World Health Organization guidelines for semen analysis: color, volume, appearance, liquefaction, viscosity, concentration, pH, leukocyte concentration, progressive motility, morphological normality, motile sperm concentration, functional sperm concentration, sperm motility index, and functional sperm. The gene of 16SrRNA (GPO1&amp;amp; MGSO primers) was used as the target gene of the Mycoplasma genus in PCR assay. Multiplex-PCR was performed with a specific primer for conserved regions in the 16SrRNA gene for M. hominis (RNAH1&amp;amp; RNAH2 primers) and the 140-kDa Adhesion Protein Gene for M. genitalium (MG1 &amp;amp; MG2 primers).According to the results,9 (9%) samples were PCR-positive for Mycoplasma spp , while there were 7 (7%) cases isolated by cultivation. M. hominis was detected in 8 (8%) samples by Multiplex PCR, while there was no evidence for M. genitalium. The mean age scores of all infertile and infected men were obtained at 31 and 30 years, respectively. The study could not show any statistical correlation between mycoplasma infection and abnormal semen parameters. The heterogeneity of mycoplasma prevalence in the reports can be ascribed to differences in geographic areas, the sensitivity of the identification method, condition of the group (fertile/infertile), sample size, and operator proficiency. Various results have been reported in numerous studies conducted on the relationship between mycoplasma infection and abnormal semen parameters.