فصلنامه دنیای میکروب ها
سال چهاردهم شماره 3 (پیاپی 48، پاییز 1400)

Despite advances in diagnosis and therapy, cancer is still the main cause of death in world. Vincristine is one the major drug in tumor treatment. However, the anti-lymphoma effects of Vincristine on micro-RNA expression are not clear, especially in B cell lymphomas. The aim of the present study was to evaluate the effects of Vincristine on miRNA-15a3p and miRNA-15a5p genes expression Epstein‐Barr‐Virus (EBV)-infected transformed B cell lymphoma. In this study, the effects of cyclophosphamide on CO 88BV59-1 LCL – an EBV infected transformed B cell was evaluated. The cells were treated with Vincristine (0.05-50 µM), for 24-72 hours. MTT, flow cytometry and real-time PCR techniques were used for cell viability, and cytotoxicity evaluations and miRNA-15a genes expression, respectively. Vincristine significantly inhibited proliferation and induced cell death in EBV infected cell-line in a dose and time-dependent manner (P<0.05). There were no significant changes in the expression of miRNA-15a3p and miRNA-15a5p in treated cells compared to untreated cells (P>0.05). The results showed that cytotoxic effects Vincristine on CO 88BV59-1 LCL is independent on miRNA-15a3p and miRNA-15a5p expressions.

Background &

Staphylococcus epidermidis is a member of the microbiota of human skin, respiratory system and gastrointestinal tract which its the most important virulence factor is the ability to form biofilms. The aim of this study was to investigate antibacterial resistance and investigation of biofilm production in clinical isolates of S. epidermidis in Guilan.Materials &

S. epidermidis were isolated from clinical specimens in Rasht. Antibiotic resistance of isolates was evaluated by disk diffusion method and phenotypic evaluation of         biofilm production capability by microplate method. The presence of genes involved in biofilm formation including icaA, icaD, bhp and aap was investigated by PCR.

Out of 70 isolated Staphylococcus epidermidis, the highest resistance was against        penicillin and vancomycin was the most effective antibiotic. In phenotypic assay, 38 isolates (54.3%) were able to produce biofilm, of which 94.7%, 55.3% and 42.1%, presence of icaA, icaD and aap genes were detected respectively. The bhp gene was not detected in the studied isolates.

The results indicate high rate of antibacterial resistance and biofilm forming ability in S. epidermidis isolates in Guilan and as a result the high potential of these isolates in              colonization, pathogenicity and acquisition of multidrug resistance.

Background &

Increasing antibiotic resistance in Acinetobacter baumannii isolates has become a major global concern today. The mechanism of the food supply through iron supply through Siderophores is one of the most important factors in the adaptation of bacteria to adverse conditions. The study of the frequency of the presence of Siderophore genes in clinical isolates      provides a high understanding of the mechanism of bacterial resistance. Therefore, in this study, we investigated the frequency of antibiotic resistance in isolates containing the Siderophore gene.Materials &

Clinical samples were collected from hospitalized patients includingrespiratory, wound, urinary, and blood samples. Biochemical tests were performed to isolate the    bacteria. A molecular sensitive polymerase chain reaction (PCR) test was performed to confirm  Acinetobacter baumannii strains and to evaluate the presence of target genes. Microbial susceptibility testing was performed by disk diffusion method according to CLSI instructions and the relationship between microbial resistance and expression of Siderophore genes in isolates was investigated.

According to PCR results, out of 64 isolates identified by biochemical tests, 28 isolates (43.75%) were identified as Acinetobacter baumannii. All 28 isolated isolates (100%) had LPS genes and 15 isolates (53.57%) had Siderophore gene with 93.3% resistance to Carbapenems and 26.6% to Colistin sulfate and antibiotics. Were identified as XDR and MDR strains.

Antibiotic resistance and the prevalence of Siderophore and LPS genes in               Acinetobacter baumannii strains are worrisome and require infection control measures including management of antibiotics and rapid identification of resistant isolates.

Background &

Nowadays, high consumption plastics such as polyethylene are         recognized as one of the major environmental pollutants by the World Environment Organization. The aim of this study was to isolate and identify native Pseudomonas bacterial strains with the polyethylene packaging degradation ability.Materials &

In order to conduct this study, soil samples were collected. In order to    isolate the isolates with polyethylene degradation ability, two methods of direct culture and       culture by pre-enrichment method were used. After culturing the bacteria in MSM medium and examining the percentage of plastic weight loss, the superior strain was selected for DNA          extraction and PCR of alk-B gene. PCR results were sequenced and examined phylogenetically.

The results of the present study showed that the percentage of degradation of                polyethylene by Pseudomonas strains was 7.2% at most and 4.5% on average. Also, all purified degrading bacteria in this study harbored alk-B gene.

The results showed that the degradation of polyethylene materials can be                significantly accelerated by using and optimizing bacteria isolated from soil. It seems that by     promoting genetic methods based on the genome of bacteria, especially the strain of               Pseudomonas aeruginosa, it is possible to develop methods during which all commonly used types of polyethylene are degraded in a much shorter time than normal.

Background &

An important part of drug resistance In Pseudomonas aeruginosa is    related to efflux pump systems. In this study, the antimicrobial effect of silver oxide nanoparticle and Lactobacillus plantarum probiotic on MexX gene expression has been studied.Materials &

In this descriptive cross-sectional study, 49 samples were collected from Mashhad and identified using standard methods. Strains with multidrug resistance were selected to determine MIC and check the frequency of MexX gene by PCR method. Broth dilution method was performed for probiotics, silver oxide nanoparticles and combination of both to obtain MIC and MBC. Microdilution method and Real time-PCR technique were used to determine the effective dilution of silver oxide nanoparticles and probiotics and MexX gene expression, respectively. The data related to the changes in MexX gene expression were analyzed by the 2-ΔΔCT  method using the independent T test in two groups.

All strains had MexX gene and all of them were resistant to more than two antibiotics. The minimum concentration of growth inhibition in the dilution method in agar was for silver oxide nanoparticles up to a dilution of 500 µg/ml and for probiotics up to a dilution of 16 µg/ml. Compared to probiotics, silver nanoparticles had a greater effect in inhibiting the growth of bacteria, and the amount of this effect is greater than the combined effect of probiotics and silver nanoparticles (P>0.05).

Silver oxide nanoparticle and probiotic have antibacterial effect to reduceMexXY-OprM efflux pump function in Pseudomonas aeruginosa bacteria.

Background &

Dental plaque is structurally and functionally a biofilm that may lead to caries and root infection due to disruption of microbial homeostasis. The present research aimed to investigate the molecular characteristics of dental flora of patients in East Tehran.Materials &

In this cross-sectional study, 9 samples of dental plaque, caries, and root canal from five patients who were randomly selected in 2017 were collected under sterile  conditions. Bacteria were cultured using the standard BHI broth culture medium. General primers of the 16S rRNA gene were used for molecular identification of bacteria and investigation of their phylogenetic relationships. Demographic characteristics of the subjects were also examined.

Thirteen bacterial isolates were identified from clinical specimens of plaque and tooth decay. The isolated bacteria belonged to three phyla, five families, six genera Arthrobacter, Brevundimonas, Granulicatella, Kocuria, Neisseria, and Streptococcus, as well as seven species. The most abundant isolates were N. perflava (n=5) and S. salivarius (n=3). The identified bacteria were arranged in four branches of a phylogenetic tree. No association was found between bacteria and demographic characteristics.

Identifying the factors involved in dental infections is an effective approach to prevention. In this study, 11 bacterial isolates from dental plaque and 2 bacterial isolates from tooth decay were identified and no strains from the root specimens were identified. The  discrepancy between plaque bacteria and caries may be due to the small sample size and  microbiological methods used.