Journal of Medical Microbiology and Infectious Diseases
Volume:7 Issue: 4, Autumn 2019

Despite considerable efforts to control AIDS pandemic, it is still one of the significant infectious concerns worldwide. The advance in medical research has led to the development of highly active antiretroviral therapy with a considerable effect to suppress the disease. However, an effective vaccine capable of eradication the HIV pandemic is not available yet. Failure to develop a prophylactic vaccine diverted the efforts to clinical trials of therapeutic vaccines.

Here, we review different approaches to dendritic cell-based HIV therapeutic vaccines. We have summarized the dendritic cell-based trials as HIV therapeutic vaccination, registered in the United States clinical trial database. Results and

The strategies applied in the clinical trials were mostly of low success rates; however, by using dendritic cell therapy, they could trigger the host immune response against HIV-1 infections.

Some strains of Escherichia Coli, including intestinal pathogenic strains, commensal strains, and extra intestinal pathogenic E. coli (ExPEC) have a significant impact on human health status. A standard vaccine designed based on conserved epitopes can stimulate a protective immune response against these pathogens. Additionally, enhanced expression at the infection site as a pathogenesis factor in disease is crucial for an ideal vaccine candidate. The IroN protein plays a role in severe infections of E. coli. Hence, this protein will assist in developing the novel and more efficient treatments for E. coli related infections. A better understanding of protein tertiary structure can help to percept their functions and also their interactions with other molecules. There is a growing interest in using bioinformatics tool to make accurate predictions about the functional, immunological, and biochemical features of target antigens.

Herein, we aimed to predict the structure of the IroN protein upon its folding and determine their immunological properties.

In the present study, using bioinformatics analyses, we identified the highly antigenic regions of IroN protein. Our designed vaccine candidate had the highest immunological properties and folded into a typical beta-barrel structure.

The approach of assigning structural and immunological properties of the target antigen to design the vaccine candidate could be deployed as an efficient strategy to circumvent the challenges ahead of empirical methods without dealing with ethical concerns of animal usage and human participants. Although the obtained results are promising, further experimental studies could bring about more insights on the efficiency of the designed vaccine.

The Nef accessory protein is an attractive antigenic candidate in the development of HIV-1 DNA- or protein-based vaccines. The most crucial disadvantage of DNA and protein-based vaccines is their low immunogenicity, which can be improved by cell-penetrating peptides (CPPs) as effective carrier molecules.

In this study, the HIV-1 Nef protein was generated in the Escherichia coli expression system for in vitro delivery using a novel CPP, Latarcin 1 peptide, in a non-covalent manner. Also, the Histidine-rich nona-arginine peptide was utilized to transfer the HIV-1 Nef gene. The size, morphology, and zeta potential of the complexes were evaluated by scanning electron microscopy (SEM) and Zetasizer. The efficiency of cell transfection was studied using a fluorescence microscopy and flow cytometry for the DNA/CPP complexes and western blot analysis for the protein/CPP complexes.

The Nef protein generated in the BL21 strain migrated as a dominant band of ~30 kDa in SDS-PAGE. The SEM data confirmed the formation of stable complexes with a size below 200 nm. MTT assay demonstrated that the complexes did not represent any considerable cytotoxic effect compared to untreated HEK-293T cells. The results of fluorescence microscopy, flow cytometry, and western blotting revealed that the Nef DNA and protein constructs could be significantly transfected into HEK-293T cell line using these CPPs.

These data suggest that the Histidine-rich nona-arginine peptide and Latarcin 1 peptide as CPPs can be considered as a promising approach in the development of the HIV-1 vaccine for gene or protein delivery.

Brucellosis is one of the most common zoonotic infections worldwide. The clinical symptoms of brucellosis are similar to a wide range of diseases; hence, reliable diagnostic and laboratory methods are required to identify the causative agent. Iran is an endemic region of brucellosis, and many patients are misdiagnosed due to the nature of the infection. In this study, we aimed to evaluate and compare the use of the conventional Wright test and quantitative polymerase chain reaction (qPCR) for the diagnosis of brucellosis.

Diagnosis of brucellosis was performed using serological tests and PCR amplification of a gene encoding 31-kDa immunogenic Brucella abortus protein (BCSP31). Data were analyzed using the Chi-square test.

Brucellosis was diagnosed in 45 (69.23%) and 22 (38.8%) patients using the Wright test and qRT-PCR, respectively. The results of Wright and qRT-PCR assays were consistent in patients with negative results (90%). Moreover, qRT-PCR detected brucellosis in 25% of patients with Wright test titers <1/160, while 55.2% of the patients were positive with titers ≥1/160. No significant association was detected between positive PCR results and age, gender, and clinical symptoms.

qRT-PCR showed a reliable diagnostic method capable of detecting the infection in suspected individuals with negative Wright results or with Wright test titers <1/160. Also, the positive qRT-PCR assays were in agreement with the Wright test titer. Regarding the financial and availability issues as well as technical problems, the agglutination test remains the preferred method in Iran.

Antibiotic resistance, especially in Gram-negative uropathogens such as Escherichia coli, is the main barrier to treat urinary tract infection (UTI). In recent years, the dramatically increased resistance of E. coli to quinolones, a group of widely used antibiotics, has become a significant concern.

In this descriptive cross-sectional study, we collected 261 E. coli isolates from the urine and stool samples of patients, referred to or hospitalized at Loghman hospital in Tehran, Iran, with either acute or recurrent UTI. The susceptibility testing for quinolones was performed by the disk diffusion method according to the recent protocols.

The frequency of resistant E. coli isolates was higher against nalidixic acid than ciprofloxacin and norfloxacin (67.8% vs. 48.7% and 44.1% respectively). When comparing acute and recurrent phases of UTI, in the urine samples, no significant difference was seen in the frequency of resistant isolates against nalidixic acid and norfloxacin, while this frequency against ciprofloxacin was significantly higher in recurrent UTI (68% vs. 48.2%). However, in the stool samples, the frequency of resistant isolates against nalidixic acid was higher in recurrent UTI (77.1% vs. 55.7%), while no significant difference was seen against ciprofloxacin and norfloxacin in these phases.

Regarding the antibiotic type and frequency of the administration, the resistance pattern of E. coli to quinolones seems to differ in acute and recurrent phases of UTI.

Pseudomonas aeruginosa is an opportunistic pathogen of clinical importance, particularly in immunocompromised and burn patients. This bacterium is becoming resistant to many antibiotics via intrinsic or acquired mechanisms. Mutations in anti-mutator genes, such as pfpI, can be a potential intrinsic mechanism of antibiotic resistance. This study aimed to evaluate the possible effects of mutations of this gene on coding proteins of multi-drug resistant P. aeruginosa isolates.

The antibiotic resistance pattern of 50 P. aeruginosa isolates against 9 anti-pseudomonas antibiotics was determined by the disk diffusion method. PCR, followed by sequencing, detected the mutations in the pfpI gene. The retrieved sequences were translated to the corresponding amino acid sequences using an online protein database. The amino acid sequences in mutated isolates were compared with the reference sequence using a multiple alignment method.

Out of 50 isolates, 43 (86%) were resistant to all antibiotics. Sequencing and multiple alignment analyses showed that amino acids in positions 21, 24, and 57 of pfpI gene were changed in resistant isolates, and all these mutations were observed in each isolate. Homology modeling showed that these amino acids were part of a cleft on the protease. The other point mutations resulted in amino acid changes were in positions 67, 83, and 165.

The data obtained in this study showed that the pfpI gene of P. aeruginosa might have a significant effect on response to antibiotics. Further epidemiologic and comprehensive studies are required to confirm these findings.

Staphylococcus aureus is a source of nosocomial infections and one of the significant concerns in patients with indwelling devices. Lysostaphin is a bacterially produced endopeptidase with a unique activity on S. aureus. Plasma, the fourth state of the material, consists of charged ions, free electrons, and activated neutral species. Biomedical applications of cold plasma are rapidly growing due to its capacity to treat heat-sensitive objects such as polymeric materials and biological samples. It activates surfaces by etching them to stabilize proteins. The direct effect of cold atmospheric plasma on the eradication of microorganisms have been investigated. However, there is no report on immobilizing antibiotic agents.

In this study, the lysostaphin protein was expressed and purified using Ni-NTA column, then the purified enzyme was immobilized on glass surfaces pretreated with cold atmospheric plasma for 150 s, 200 s, and 300 s. The antimicrobial activity of immobilized lysostaphin on S. aureus was approved by in vitro analysis.

The 300 s plasma treatment confirmed to be the best time arrangement for more lysostaphin immobilization, shown by Atomic Force Microscopy.

Our results showed that passive adsorption to the treated surface does not affect the structure and subsequent antimicrobial function of the recombinant protein compared to the standard proteins.