نشریه میکروب شناسی پزشکی ایران
سال چهاردهم شماره 4 (امرداد و شهریور 1399)

  Regarding the availability of an effective vaccine against hepatitis B virus, global vaccination is the best cost-effective strategy to prevent HBV infection. However, some people may not respond to the vaccine or the titer of antibody decreases by time. Therefore, the present study aimed to determine the frequency of anti-HBs antibody (anti-HBsAb), among university students in Fars province, southern Iran.

 In this cross-sectional study, 825 medical students were enrolled. Blood samples were taken from the subjects, and the serum separated and stored at – 20 ºC until use. Next, HBs Ab titer was measured by ELISA method.

 Out of 825 students 54% was male and 46% were female. The mean age of the students was 19.5±1.9. The titer of anti-HBsAb in 529 (64%) of subjects was lower than 10 mIU/mL. Significant relationship was observed between age and the titer of anti-HBsAb (P=0.001), although no significant relationship was observed between gender (P=0.19), history of blood transfusion (P=0.58) and the titer of anti-HBsAb.

 Finding of this study showed that the titer of anti-HBsAb in more than half of students was lower than 10 mIU/mL and by time the anti-HBsAb titer decreased, indicating the necessity of measurement of anti-HBsAb titer in medical students.

Staphylococcus aureus is one of the most important microorganisms that can colonize the human body and cause various types of human diseases by secreting virulence factors. The lateral flow assay (LFA) is one of the well-known commercial immunoassay methods that provides a high sensitive and rapid approach to monitoring infectious agents in blood, serum and urine. LFA has been considered as an ideal immunochromatographic test.

Anti Staphylococcal Enterotoxin B (SEB) antibodies were conjugated to 20 nm colloidal gold nanoparticles and were applied in assembled lateral flow layer. Suitable reagents were prepared and used in silver enhancement method. We designed a single immunochromatographic test strip to detect SEB.

In this study, the smallest amount of SEB identified using sandwich LFA method was 10 ng/mL. We also established a "silver enhanced method". Silver could improve the sensitivity detection of the test 100-fold greater than the previously mentioned sandwich LFA.

Regarding the high sensitivity of the new method for detection and measurement of SEB (0.1 ng/mL), this strip test offers great promise for a rapid technique instead of the other diagnostic SEB tests in laboratories for the first time.

Due to the increase in gastrointestinal diseases, the use of low-potency herbal medicines for treatment has increased. The synergistic effect of Glycyrrhiza glabra and Astragalus gossypinus on the healing of gastric ulcers is the aim of this study

The both plants were harvested and extracted. The most appropriate dose for the use of Glycyrrhiza glabra extract in experiments, 200 mg / kg / day, was determined by performing writing tests and carrageenan. Then, to create of gastric ulcer in rats, rats were gavaged for 3 days with a dose of 200 mg/kg/day of dissolved aspirin in 1% Carbocyte methylcellulose. The groups were treated with dose 200 mg / kg / day (Concentration of 0.363 mg / ml) of both extracts and distilled water for 14 days. Four gastric ulcer rat groups, respectively, received both extracts, Glycyrrhiza glabra extract, omeprazole and distilled water as a positive control group, and the fifth group or negative control group Without gastric ulcer received distilled water. After the treatment period, the rats were described and ulcers were examined under microscopic and pathological examination.

Both extracts together (200 mg/kg/day) reduced the wound coefficient significantly (P <0.01) compared to the two control groups. The percentage of wound healing was increased than the positive control group (omeprazole) 90.27% and the negative control group (distilled water) 91.53%. Pathologic examination confirms microscopic findings.

The statistical evaluation of the results shows that the effects of gastric ulcer as a result of the consumption of Glycyrrhiza glabra are very low and valuable. (P<0.01) Also, the use of both extracts together is not synergistic.

Following the outbreak of SARS-CoV (Severe Acute Respiratory Syndrome coronavirus) in 2002 and the outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012, we are facing the rapid spread of SARS-CoV-2 (COVID-19) in the world in 2019. Several outbreaks of the virus and its widespread prevalence have necessitated the design of drugs and vaccines in the shortest possible time. This is not possible except by using bioinformatics tools. In this study, the binding of drugs affecting RNA Polymerases to SARS-CoV-2 RNA-dependent RNA polymerase structure was simulated by molecular docking method.

The structure of drugs used to treat COVID-19 and their similar structures from the drugbank database received. It was then subjected to molecular docking by AutoDock Vina software, and the structure with the most negative affinity was docked to reconsider its connection location. Finally, the amino acids involved in binding were investigated by Discovery Studio software.

In the test with in silico status, the Rifabutin had the best performance for SARS-CoV-2 RNA-dependent RNA polymerase binding, and the binding site identified for this drug was different from the binding site shown in the PDB database.

Further research on the Rifabutin could be the key to discovering new drugs for COVID-19.

Rabies is a deadly zoonotic disease that is caused by the rabies virus. The virus can infect and disrupt the central nervous system of a rabid patient. The rabies virus is a neurotropic single stranded RNA virus. Glycoprotein (G) is the most important protein that binds to the cellular receptors and also induces an immune response against the virus in the host. Using reverse genetics technology, the glycoprotein gene could be modified and a virus with higher immunogenicity or lower pathogenicity.

In this study, we designed a mutation in the sequence of glycoprotein gene using a software, on the main antigenic site II of the Pasteur virus strain at the position of 42-34 amino acids. Agene fragment in the cloning vector containing the rabies virus genome was replaced by the synthesized construct containing the altered gene by two restricted enzymes, and then cloned. The T7-BHK cell under the T7 phage promoter control was transfected to express the glycoprotein gene, along with the construct and vectors expressing the N, P, and L genes of the rabies virus as well as the full genome. After expressing and confirming viral genes, it was cultured and amplified in BSR cell.

after cloning and expression of the recombinant virus in the target cell, the vector containing the mutated gene led to the rescue of the recombinant virus. The recombinant virus cultured and propagated in the BSR cells, then the genome was extracted and finally confirmed by sequencing.

The rescued recombinant virus can be used for research studies or in the vaccines manufacturing, provide that the antigenicity is maintained or increased.

In recent years, the use of medicinal plants has increased due to their lower side effects and costs compared to chemical drugs and patientschr('39') adaptation to these drugs. This study was performed to investigate the antibacterial effect of aqueous and alcoholic extract of four native medicinal plants of Gilan province against the bacterium Klebsiella pneumoniae.

In this study, plant species were collected from different areas of Gilan province and extraction was performed. The antibacterial effect of the extracts was investigated by the disc diffusion method. Then, using microdilution method, the minimum inhibitory concentration of bacterial growth was determined.

The results showed that chamomile alcoholic extract with the maximum average halo diameter of 14 mm showed the best effect against K. pneumoniae. The bacterium showed resistance against the aqueous and alcoholic extracts of fleawort. Also, the ethanolic extracts of nettle and chamomile plants had the best antibacterial effect at 0.39 mg/ml. The minimum inhibitory concentration of aqueous extract of fleawort plant against Klebsiella pneumoniae was 12.5 mg/ml which was lower than other types of extracts. According to the results, these extracts can be used as antibacterial products in the pharmaceutical and food industries and in the treatment of infection symptoms.

Pathogens’ resistance to antibiotics is one of the major problems in Iran and worldwide, which has caused the healthcare system to face many problems dealing with infectious agents. Following the prevalence of Covid-19, people with mild symptoms have avoided seeking medical attention while preferring self-medication. This has exacerbated the crisis of antibiotic resistance. Here we aimed to investigate the effect of the prevalence of Covid-19 on the overuse of antibiotics.

The data gathering tool was a researcher-made questionnaire. The study’s target population was the servants of the holy shrine of Fatima Masumeh (PBUH) and members of Vanak Park Complex located in Tehran. A total of 168 people participated in this research and the results were summarized and presented as percentages and graphs.

 20.8% of people used antibiotics during the outbreak of Covid-19, of which 20% said that the outbreak of Covid-19 and quarantine prevented them from going to medical centers and self-medicating. In this case, it can be concluded that fear of coronavirus disease has affected the rate of referrals to medical centers and the intensification of self-medication and overuse of antibiotics, and finally the crisis of antibiotic resistance.

 Pseudomonas aeruginosa infections are resistant to antimicrobial agents and produce toxic virulence factors such as exotoxin A. Studies have shown that some nanoparticle compounds and antibiotics have a synergistic effect. Therefore, the aim of this study was to investigate the synergistic effect of silver nanoparticles and erythromycin on antibiotic-resistant P. aeruginosa.

 In this descriptive cross-sectional study, 40 cultured samples of burn wound secretions were taken from Imam Musa Kazem (PBUH) Burns Hospital in Isfahan, Iran. Diagnostic and differential tests were performed. Antibiogram was performed to obtain the bacterial resistance pattern and the exotoxin A gene was detected by PCR. The bacterial minimum inhibitory concentration (MIC) was then applied to the silver nanoparticles (shape and mean size) and erythromycin separately and a common mixture of both in 10 dilutions to investigate the synergistic effect.

   A number of 26 bacteria were strains of P. aeruginosa. Of samples, 25 (96.15%) had exotoxin A gene. All samples were sensitive to all erythromycin concentrations. The mean MIC of nanoparticles against bacteria was reported to be 2 μg/mL. A solution of 40 μg/mL erythromycin and 2 μg/mL nanoparticles was also considered as MIC solution. Pseudomonas aeruginosa is sensitive to erythromycin to very low concentrations of silver particles. But no synergistic effect between silver nanoparticles and erythromycin was reported for this bacterium. Based on PCR results and antibiotic resistance pattern, a significant number of the samples contained the exotoxin A gene and the use of erythromycin alone was not appropriate for treatment.