دو ماهنامه میکروب شناسی پزشکی ایران
سال چهاردهم شماره 6 (آذر و دی 1399)

Acquired Immune Deficiency Syndrome (AIDS) is a descriptive type of immune system dysfunction disorder which is caused by HIV infection. Since its discovery, HIV has been responsible for the death of more than 25 million people worldwide, and many people are infected with HIV each year. Because of the structural complexity of the virus and the lack of a promising vaccine, several antiviral drugs, and nucleic acid therapies such as siRNA have been studied and evaluated for the HIV prevention. The antiviral treatments have considerably improved the quality and hope of life for the infected people, but along with the capacity to adapt to the virus, it has prevented further success. Nanotechnology approaches have had a positive impact on the prevention and treatment of different diseases. Various nanoparticles and substances have been evaluated for the antiviral drugs improvement for the prophylaxis and treatment of AIDS. Some nanoparticles which have been discussed in this article include liposomes, dendrimers, gold nanoparticles, polymeric nanoparticles, nanofibers, silver nanoparticles, and drug nanocrystals. In this review study, the nanotechnology approaches, the structure and properties of nanoparticles and their function in the prophylaxis and treatment of HIV were discussed.

Helicobacter pylori (H. pylori) has been identified as the major agent in human gastric cancer by the International Agency for Research on Cancer (IARC). Infection caused by H. pylori plays a leading role in many disorders including duodenal and gastric ulcer, chronic gastritis, lymphoid tissue lymphoma, and gastric adenocarcinoma. In addition, growing evidence suggests that H. pylori interferes with many biological processes, causing or affecting the incidence of several extra-gastrointestinal disorders. The bacteria are known to cause iron deficiency anemia (IDA), vitamin B12 deficiency, and immune thrombocytopenic purpura (ITP). Latest studies suggest that H. pylori may contribute in many disorders such as insulin resistance, acute coronary syndrome, neurological diseases among others, which previously was attributed to other factors and conditions. There are several mechanisms proposed for H. pylori inducing low-grade chronic inflammation and the incidence of molecular imitation mechanisms. This present study discusses the most critical diseases related with the role of H. pylori and related infection (especially extra-gastrointestinal diseases) in these diseases.

 Acinetobacter baumannii is a non-fermentative gram-negative coccobacill that has high level of resistance to antimicrobial agents. Biofilm formation is an important feature of most clinical isolates of Acinetobacter spp, this led to higher resistance to antibiotics. The current study aimed to assess the ability of biofilm production and to determine the frequency of bap gene in clinical isolates of Acinetobacter baumannii.

 This descriptive cross-sectional study was performed on 165 strains collected from hospitals of Tehran in 2019 and confirmatory tests were performed to identify the bacteria.  The antibiotic resistance pattern of the isolates was determined by disk diffusion method against 10 antibiotics and also the ability of biofilm production was evaluated by microtiter plate method (MPT) and tube method (TM). Subsequently Molecular assays of blaOXA-51 and bap genes identification and its frequency were investigated.

 In this study, among 165 isolates examined, 73 isolates were confirmed as Acinetobacter baumannii. Among 73 strains studied the most antibiotic resistance was imipenem (94.52%). blaOXA-51 and bap genes were detected in 100% and 53.42% of isolates. Also, 8 isolates (10.95%) by MTP and 7 isolates (9.58%) by the TM method were able to form strong biofilm.

  The results obtained showed that in consistent with other researches, biofilm formation in Acinetobacter baumannii isolates was associated with present of bap gene.

 Dictyocaulus viviparus nematode is the cause of severe bronchitis in dairy animals which lead to significant economic losses in the industry of this type of livestock. The present study aimed to determine the incidence of D. viviparous, a highly endemic parasite in cattle and water buffaloes in Guilan province, Iran.

Stool samples from 212 cows and 189 buffaloes were tested using the Baermann technique. After slaughtering the animals, the lungs of all cows and buffaloes were isolated, sampled and carefully studied to determine D. viviparus in the lungs.

 In general, there was a significant difference in the prevalence of D. viviparus in the fecal samples of cows (22.64%) and buffaloes (26.32%). Macroscopic study revealed symptoms of severe pneumonia, nodular lesions, and hyperemia in lung tissues of 5 cows and 5 buffaloes. Microscopic (histopathological) studies showed lymphocytic bronchiolitis and multifocal eosinophilic with wide interalveolar walls in lungs infected with D. viviparus.

  The prevalence of this parasite among cattle and buffaloes were 22.64% and 26.32%, respectively; but the difference between these two animal species was not significant. Overall, the prevalence of D. viviparus was higher among young animals in both species.

 One of the medicinal fungi that has been used in traditional medicine for a long time is the Basidiomycete fungus Fomes fomentarius, which is widely distributed in Iran. Polysaccharides as one of the metabolites of this fungus have anti-inflammatory, anti-diabetic, antibacterial, antioxidant, and anti-cancer properties.

   Optimization of independent variables of MgSO4.7H2O concentration, initial pH, yeast extract, and inoculum percentage to increase biomass and polysaccharide production of F. fomentarius was investigated using the Taguchi method. Then, the biological properties of the produced polysaccharide including antibacterial activity was investigated by bacterial colony counting method, antioxidant activity using DPPH free radical, and antiproliferative effect on 5 cancer cell lines MKN-45, AGS, A549, KYSE-30 and 5637 using MTS test.

   The concentration of MgSO4.7H2O and initial pH had a significant effect (P<0.05) on the production of F. fomentarius polysaccharide and in optimal conditions polysaccharide production reaches 5.410 g/L. The polysaccharide of this fungus inhibits the growth of Staphylococcus aureus and Escherichia coli bacteria by 50% and 25%, respectively. The antioxidant activity of this polysaccharide in the DPPH test is 16.11%. The antiproliferative effect of this polysaccharide on cancer cells is different (KYSE-30> A549 5637> AGS> MKN-45). This effect increases with increasing concentration. In KYSE-30 cell line treatment with 200 g/mL polysaccharide, cell viability reaches 40% after 72 hours.

  Optimizing the culture medium of the medicinal fungus Fomes fomentarius increases the production of polysaccharides up to 5.410 g/L. Optimization increases the biological activity of polysaccharides. Antibacterial activity against Staphylococcus aureus and Escherichia coli is 50% and 25%, respectively. The antioxidant activity of polysaccharides is 16.11% and the viability of KYSE-30 cancer cells reaches 40% after 72 hours.

 Dermatophytes are common causes of cutaneous infections in humans and animals, which mostly reproduce by an asexual process. Such types of reproduction in many filamentous fungi are usually regulated by brlA, abaA, and wetA genes. The presence of these genes in dermatophytes was investigated.

Conidiation genes represented by brlA, abaA, and wetA were determined in seven strains of dermatophytes using a polymerase chain reaction (PCR) method.

  All strains of Microsporum canis and one strain of Microsporum ferrugineum (MH383043) were shown to have all three specific conidiation genes, which were absent in other strains, except for Trichophyton interdigitale which had only the abaA gene.

  Dermatophytes content of brlA, abaA, and wetA genes is variable and strain-dependent. The conidiation process in most dermatophytes is assumed to be under the control of other genes not included in this study.

 Cancer is one of the most common causes of death in humans. Therefore, there is a need for new cytotoxic compounds from natural sources such as native bacteria. The current study aimed at investigating the cytotoxic effects of compounds obtained from gram-positive terricolous bacteria on the apoptosis of cells in prostate cancer (PC-3).

   A total of 70 soil samples were obtained from various locations in Chaharmahal & Bakhtiari province (Iran, Spring 2020) and were cultured on Nutrient agar and Trypticase soy agar. After identification of gram-positive species, the best species in regards to microbial activity was identified using 16S rRNA gene sequencing. Then, in order to investigate the cytotoxic activity, PC-3 cell line was treated in different concentrations of the supernatant from the selected species for different durations while viability and apoptosis were determined using MTS and Annexin tests.

   A total of 467 gram-positive bacteria were extracted from 70 soil samples, among which 9 species had antimicrobial capabilities. Among these selected species, Bacillus licheniformis which had the best antimicrobial compounds, was selected for further investigation of its viability and apoptosis effects on PC-3 cell line. The MTS with incubation time of 24, 48 and 72 hours of the treated cells indicated that the viability is dependent on the dosage an increase in the concentration can result in significant decrease in the viability compared to the control group (P<0.05). The amount of apoptosis induction in PC-3 cells also significantly increased with increase in supernatant concentration dependent on dosage and time (P<0.05). The largest effect was observed at supernatant concentration of 20 mg/mL at 72 hours after cell treatment.

   Using compounds obtained from gram positive terricolous bacteria can help in treatment of prostate cancer cells.

 Influenza viruses cause Avian Influenza (AI) is a serious infectious disease belonging to type A Orthomyxovirus. A viral RNA synthesis is due to an interaction of the nucleoprotein (NP) with the viral polymerase. In the present study, we have evaluated the immunogenicity of avian influenza virus nucleoprotein.

   An Influenza Virus N9H2 subtype A/Chicken Iran/259/2014 was selected. In order to perform electrophoresis and purification of nucleoprotein, the protein concentration of the samples was determined. SDS-PAGE and Native-PAGE electrophoresis on polyacrylamide gel were done and differences in gel bands in two methods were compared. Purification of the virus nucleoprotein performed by electroelution method and purified nucleoprotein were assayed by ELISA to obtain the produced antibody titers. Ouchterlony and western blot tests were used for final approval.

   By determining the molecular weight of each polypeptides, the molecular weights of H9N2 proteins were ranged from 30 to 140kDa and the molecular weight of the nucleoprotein was 60kDa. The nucleoprotein was purified by electroelution method. Ouchterlony showed that in serum dilution of 1:2 and 1:4, the sediment lines were formed between the serum and the NP antigen. The NP-ELISA enables rapid serological diagnosis in 1:20. Finally, the western blot test confirmed the 60kDa nucleoprotein band.

  The nucleoprotein which was purified by electroelution retained its antigenic property and it could be applied in diagnostic kits.