فهرست مطالب hatef ajoudanifar

Nosocomial infections are a global problem that has become a challenge in hospitals around the world since the 80s. One of the main sources of hospital infections is personnel. In this regard, the present study aimed to investigate the frequency, colonization rate, antibiotic resistance, and molecular types of Staphylococcus aureus in the personnel of key hospital departments, including emergency, infectious, Coronary Care Unit, and Intensive Care Unit Departments.

Nasal swab samples were collected from the personnel of the Emergency, Infectious, Coronary Care Unit, and Intensive Care Units Departments in the fall of 2021 and subsequently cultured. Confirmation of S. aureus strains was performed by biochemical tests, disk diffusion method, and agar screen test. Moreover, polymerase chain reaction for the evaluation of resistance genes was performed. Determination of agr group, determination of SCCmec type, and checking the presence of pvl, tst, and etc genes were also performed.

In total, 75 out of 214 staff nasal swab samples contained S. aureus. Prevalence of methicillin-resistant S. aureus was 65.3% confirmed by PCR test results. Based on the study of SCCmec types in MRSA strains, the most common type was SCCmecIII. Among the agr groups, type I was the most common, and in terms of the abundance of pvl, tsst, and etc genes, a relatively high prevalence was observed.

Due to the increased level of personal and environmental health in hospitals, s. aureus colonizing the noses of personnel are more pathogenic and resistant due to the natural selection of strains. Therefore, they can cause more severe diseases following transmission to the patients.

The present study aimed to investigate secondary bacterial infections among patients infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Coagulase-negative Staphylococci can infect immunocompromised patients. Linezolid resistance among Staphylococcus epidermidis is one of the most critical issues. In 2019, 185 SARS-CoV-2-positive patients who were admitted to North Khorasan Province Hospital (Bojnurd, Iran), were investigated. Patients having positive SARS-CoV-2 reverse transcriptase real-time polymerase chain reaction (RT-PCR) test results, who had a history of intubation, mechanical ventilation, and were hospitalized for more than 48 hours were included. After microbiological evaluation of pulmonary samples, taken from intubated patients with clinical manifestation of pneumonia, co-infections were found in 11/185 patients (5.94%) with S. epidermidis, Staphylococcus aureus, and Acinetobacter baumani, respectively. Remarkably, seven out of nine S. epidermidis isolates were linezolid resistant. Selected isolates were characterized using antimicrobial resistance patterns and molecular methods, such as Staphylococcal cassette chromosome mec (SCCmec) typing, and gene detection for ica, methicillin resistance (mecA), vancomycin resistance (vanA), and chloramphenicol–florfenicol resistance (cfr) genes. All of the isolates were resistant to methicillin, and seven isolates were resistant to linezolid. Nine out of 11 isolated belonged to the SCCmec I, while two belonged to the SCCmec IV. It should be noted that all patients had the underlying disease, and six patients had already passed away.The increasing linezolid resistance in bacterial strains becomes a real threat to patients, and monitoring such infections, in conjunction with surveillance and infection prevention programs, is very critical for reducing the number of linezolid-resistant Staphylococcal strains.

 In the COVID-19 era, co-infections can lead to an increase in morbidity and mortality. Normal flora bacteria can transfer to the pulmonary tract and create bacterial co-infections. The nasal cavity is one of the main areas housing normal flora in the human body.

 In this study, we evaluated the prevalence and antibiotic resistance of gram-positive cocci in the pre– and post–COVID-19 eras among health care workers.

 We assessed 376 nasal swabs from the pre–COVID-19 era and 376 from the post–COVID-19 era. Conventional and molecular methods were used to identify bacterial types and evaluate antimicrobial resistance.

 The most common gram-positive cocci in the pre–COVID-19 samples were Staphylococcus aureus, S. epidermidis, S. capitis, S. hominis, S. haemolyticus, Streptococcus pneumoniae, and Enterococcus faecalis. In the post–COVID-19 samples, the most common gram-positive cocci were S. aureus, S. epidermidis, S. warneri, S. hominis, and E. faecalis. We observed higher resistance rates in post–COVID-19 samples, as well as resistance to linezolid and vancomycin in S. aureus, S. epidermidis, and S. hominis. Additionally, our isolates showed a high resistance rate to antiseptics.

 It seems that after the beginning of the COVID-19 pandemic, due to the change in the protective procedures in hospitals, the prevalence and variety of bacteria have decreased, but instead, they have been replaced by more pathogenic bacteria with higher antibiotic resistance.

The most common type of cancer is skin cancer, especially in men. Lacticin 3147 is a bacteriocin from the lantibiotic family. Since it is similar to nisin, Lacticin was considered for its anticancer properties’ investigation. The aim was to investigate the effect of Lacticin 3147. The MTT Assay helped assess A431 cell survival and cytotoxicity following treatment with Lacticin 3147 after 24 and 48 hours. The cell apoptosis amounts were investigated by measuring the activity of caspases 8 and 9 in A431 cancer cells treated with the IC50 concentration of Lacticin 3147 after 24, 48, and 72 hours. The Boyden Chamber method evaluated the invasion ability of A431 cancer cells treated with a sublethal dose of Lacticin 3147. Specific primers were designed for proapoptotic genes bax, antiapoptotic bcl-2, and the reference gene ꞵ-actin. The expression level in A431 cells treated with IC50 concentration of Lacticin 3147 was investigated using the quantitative Real-Time PCR method. Data were analyzed by SPSS 16 software and ANOVA statistical test (P<0.05). Statistical analysis of the data obtained from the MTT test showed that the growth of cells treated with different concentrations of Lacticin 3147 decreased significantly (p<0.001). The inhibitory effect of Lacticin 3147 on the viability of A431 cells depends on the concentration and treatment time. As a result, a 0.3 µM concentration and 72-hour duration were the most consequential effects. Lacticin IC50 concentration was equal to 0.8 µM. The activity of caspases 8 and 9 in the treated A431 cancer cells increased in a time-dependent manner, and after 72 hours, it was 2.36 and 2.72 times compared to the control, respectively (p<0.001). The invasion activity of A431 cancer cells treated with the sublethal dose of Lacticin 3147 decreased in a dose-dependent manner. The lowest invasion activity was at concentration of 0.5 µM with minimal lethal effect (p<0.001). The expression of the bax proapoptotic gene in A431 cells treated with IC50 concentration of Lacticin 3147 increased significantly (p<0.001). Also, the antiapoptotic bcl-2 gene expression reduction was significant in the same conditions. As a result, the use of Lacticin 3147 in the future may lead to a new strategy for the treatment of skin cancer.

Cancer chemotherapy is a big challenge due to the adverse effects of anticancer drugs. Therefore, the effort is to use natural products with therapeutic and safe potential to treat all kinds of diseases. This research aims to discover the anticancer potential of the prebiotic Bovicin HC5.The survival rate of Huh-7 human hepatocellular carcinoma cells after treatment with different concentrations of Bovicin HC5 was investigated by MTT assay. Assays of caspase 3, 8, and 9 activities in Huh-7 cancer cells treated with the Bovicin HC5 IC50 concentration were conducted to determine the degree of cell apoptosis. Boyden Chambers were used to assessing Huh-7 cancer cells' invasion ability after being treated with sublethal doses of Bovicin HC5. Using specific primers and the Real-Time PCR method, proapoptotic bax and antiapoptotic bcl-2 expression levels in Huh-7 cells treated with the Bovicin HC5 IC50 concentration were quantified. ANOVA statistical test was used to analyze the data (p<0.05).The results of the MTT test showed that the viability of Huh-7 cells treated with different concentrations of Bovicin HC5 decreased significantly depending on the concentration and treatment time (p<0.001). As a result, a 400 µM concentration and 72-hour duration resulted in the greatest effects. The IC50 concentration of Bovicin HC5 was determined to be 300 µM. The activity of caspases 3, 8, and 9 in treated Huh-7 cells increased significantly after 72 hours in a time-dependent manner and compared to the control by about 1.9 times (p<0.01), and 2.36 times (p<0.01) and 2.62 times (p<0.001)

Introduction and objective:

Aspergillus refers to a genus of fungi which has been widely used in industry. Some of the species of this genus can contaminate agricultural crops such as pistachio and corn. In addition to destructive impacts on quality of the agricultural crops, they can result in poisoning and carcinogenity in living creatures including human. Rhizopus belongs to the family of opportunistic fungi and is categorized in zygomycetes branch; this fungus is also known as black bread mold. The vegetative mycelium of this fungus has a structure called sporangiophore. At the end of the sporangiophore, there is a dome-shaped body called columella. Vesicles are situated around the columella and are called sporangium. Inside the sporangium high numbers of sporia sporangio spores can be found. The aim of this study is to extract DNA of lipase-producing oryzae species from natural resources.

the samples were cultured on PDA. For enzyme production, mineral culture medium was used for solid state fermentation. The impact of carbon source, initial pH and incubation temperature on enzyme production was also addressed. After preparing spore suspension, solid state fermentation was carried out. The enzymes were extracted after fermentation and their enzymic activities were investigated. The samples’ DNA was extracted by boiling method, and their sequence was designed by specific primer. Sequencing was carried out after PCR.

most of Rhizopus oryzae genus species have high lipase activity and can produce lipase enzyme. Regarding abundance of this fungus in the country, it can be used as a significant genus in biotechnological and industrial activities. Based on present screening, the majority of local species can produce lipase. Rhizopus delemar strain BVKT R1and 8 Rhizopus oryzae isolate FPZSP368 have high lipase activity and can be regarded as promising isolates for production of this enzyme in large scales.

Protective Antigen of Bacillus anthracis (PA) is a protein that binds to receptors on OF human body cells. There is special Urokinase plasminogen activator receptor on cancer cells and PA can not bind to them. The aim of this study is modify the receptor of PA with site directed mutagenesis that the protein can only be bind to the cancer cells.

In this study, pMNA1 plasmid that contained PA gene was extracted and site directed mutagenesis done with SOE PCR on PA gene. Mutant gene cloned on pTZ57R vector directly and transformed into E. coli DH5α with CaCl2 method. Finally exiting of the gene and mutation on PA evaluated with PCR , digestion and sequencing.

PA gene separated with PCR and mutated with SOE PCR. Mutated PCR product cloned on pTZ57R vector and earned 5.1 kb plasmid. Recombinant plasmid evaluated with digestion and PCR. Mutation confirmed with sequencing. Conclsion: Cancer has a deadly disease. One of the methods for treaeting cancer using bacterial toxins. Therefore Using a modified PA protein that binds to the cancer cells can create new hope for cancer treatment.

Aim And The immune antigen of Bacillus anthracis is a protein that can attach to the surface receptor of all human cells. At the surface of cancer cells there is a receptor that activates the uPA (Urokinase plasminogen) that do not exist in normal human cells. This research was conducted to change the site of attachment of PA gene with making direct mutation so that it can attach only to the cancer cells. In this study, pMNA1 plasmid containing PA gene was extracted from its host by basic lyse. Subsequently, phosphorylized primers and Overlap Extention PCR were used to make mutation on PA gene. The mutated segment was directly cloned in PTZ57R carrier and transferred to DH5α strain of E. coli. By catalyst enzymes KpnI and SalI the mutated PA gene was extracted and transferred to pWB980and by electroporation method it was transferred to WB600 strain. In this study mutation was occurred in sequences of PA gene by SOE PCR method resulting in a change in the genetic code of amino acid 194. The occurrence of mutation was confirmed by determining of base sequences. Cancer is a serious disease that in many cases leads to death. One of the treatment methods of cancer is bacterial toxins if only cancer cells receive them. Therefore, using changed PA can be a hope in cancer treatment as it attaches only to cancer cells.

Aims and Cellulose is the most widely used biopolymer to produce paper, textiles and biomedical materials. One of the interesting methods to produce cellulose is microbial resource due to the shortage of cellulose original resources. On the other hand, the use of microbial cellulose as a pure polymer and absence of lignin and hemicellulose is preferred. The present study was aimed to isolate Pseudomonas luteola producing cellulose bacterium to produce cellulose and evaluate its production quality. Samples from different local vinegars, juices and fruits were cultured in Hestrin-Schramm agar medium. Pseudomonas luteola was isolated with biochemical tests and verified by 16S rRNA typing method. After cultivation of the isolate in Hestrin-Schramm broth, cellulose was produced in medium. The cellulose layer was treated by SDS and NaOH, then purified and dried. Finaly, the produced cellulose was verified by cellulase enzyme and scaning electron microscope (SEM). In this study, the gram-negative organism Pseudomonas luteola was isolated and identified. Then, the isolate was cultured in Hestrin-Schramm broth and cellulose was produced after 6 days incubation at 30°C. The enzymatic digestion results were showed that the cellulose has been presented in culture medium. Scaning Electron Microscope (SEM) image was revealed that the produced cellulose by the isolate has fibrous and plexiform structure. This is the first report on cellulose production by native isolate of Pseudomonas luteola in Iran. The quality of produced cellulose by the organism is appropriate in comparison with the cellulose produced by standard strain, thus is presented to produce cellulose as a new resource.

Background &

Approximately 98% of total potassium in soil is in unavailable mineral forms for plants. Potassium-solubilizing bacteria are able to dissolve potassium bearing silicate minerals and release available form of potassium to the plants. The present study was intended to isolate potassium-solubilizing bacteria from rhizosphere soil of crop plants and to evaluate the ability of isolates in solubilisation of absorbable potassium. Material &

Potassium-solubilizing bacteria were isolated from the rhizosphere of different crop plants. The isolates were grown on optimized Aleksandrov agar and were assayed based on the diameter of zone of potassium solubilization. The selected isolates were identified using macroscopic, microscopic, biochemical, and molecular methods. The Flame photometry was used to quantify potassium released by isolates in Aleksandrov broth and soil.

Totally, 5 out of 30 isolates with ability to release potassium showed high activity in potassium solubilisation. The biochemical and molecular studies indicated that these isolates belonged to the genera Bacillus, Paenibacillus, and Pseudomonas. The flame photometry results showed that the amount of potassium released by the isolates ranged from 950 to 1250 mg/l in broth media and 525 to 550 mg/kg in soil.

The potassium-solubilizing bacteria were isolated and identified from rhizosphere samples and identified. These isolates showed high ability for solubilisation of silicate minerals and release of absorbable potassium and therefore they can be used in biofertilizers to enhance the availability of potassium in the soils and to improve the growth and yield of crop plants.

 S. simulans is a gram-positive cocci that can be isolated  from skin and urine, as well as some clinical samples in human and animals, such as bovine mastitis. The present study was aimed to isolate and identify S. simulans, a lysostaphin-producing organism, from bovine mastitis and to test therapeutic property of this species against the staphylococcal infections. This cross- sectional study was done on the collected samples from breast of the cows afflicted to mastitis in Damghan, Semnan Province. The samples were cultured on nutrient agar and were examined based on Gram staining and biochemical tests. Then, the genomic DNA of the samples suspected for S. simulans were extracted. The accurate identification of the bacteria and tracking of lysostaphin gene were evaluated by using PCR and sequencing. One out of 61 gram-positive isolated cocci from bovine mastitis samples was detected as S. simulans. This result was verified using 16S rRNA sequencing.  This study is the first report of isolation of S. simulans, a lysostsphin-producing organism, from bovine mastitis. This species is potentially useful for extraction of lysostsphin which is applied for treatment of the infections caused by antibiotic resistance bacteria.