International Journal of Molecular and Clinical Microbiology
Volume:10 Issue: 1, Winter Spring 2020

Trimethoprim is a bacteriostatic and broad-spectrum antibiotic used to treat infections, particularly urinary tract infections. Among dfrA genes, its five genes including dfrA1, dfrA5, dfrA12 and dfrA17 which release resistance to trimethoprim, are more important. This study tends to evaluate the frequency of encoding trimethoprim resistant genes in clinical specimens. First, clinical specimens were isolated from patients hospitalized in the Pars Hospital and cultured on blood agar and EMB. Differential tests were used to detect and isolate gram negative bacteria. Then, antibiotic sensitivity test was performed by disk diffusion agar method according to CLSI 2018 protocol. After detection of trimethoprim resistant bacteria, genomic DNA was extracted from them. Polymerase chain reaction was performed using dfrA primers to detect the presence of genes producing resistance to trimethoprim. Statistical analysis of results of polymerase chain reaction showed that dfr1 gene, followed by dfr5 and dfr17, was the most frequent among strains of gram negative bacteria in the statistical population. The presence of dfrA genes plays an important role in antibiotic resistance to trimethoprim.

Protease is an enzyme with various uses in medicine, industry and textile. One of the most important sources of protease production is bacteria such as Streptomyces. So, the aim of this study was cloning and sequencing of the protease gene in the Streptomyces spp isolated from Persian Gulf in Escherichia coli XL1blue. After collection of marine sediments from the Persian Gul, Streptomyces strains were identified using standard laboratory tests. All isolates were confirmed using 16S rRNA amplification test. Protease encoded gene were identified using specific primers in the PCR method. Protease gene was cloned in the E. coli host vector by TA cloning technique and finally the expression of the genes was measured using Real-time PCR method. ClustalX and Mega5 software were used to draw the phylogenetic tree. Twelve isolates of Streptomyces were isolated and 25% (n; 3/12) of them were positive for protease gene. After cloning of the gene, colony selection (blue / white colonies) were used for identification of success cloned strains. A relative expression of the protease gene was shown by real-time PCR test. Phylogenetic tree with the neighbor joining method show that, Streptomyces spp with bootstrap values 99% located in a clade which indicated their close relatedness. Protease enzyme production was performed by recombinant plasmid and TA cloning, and further studies could be helpful to optimize different conditions for this enzyme production. So, The Persian Gulf is a large pool for the protease producing Streptomyces for medical and industrial use.

Urinary tract infection (UTI) is one of the most prevalent diseases in human. Unfortunately, the indiscriminate use of antibiotics leads to resistance in bacteria gradually. The aim of this study was to determine the antibiotic resistance pattern and frequency of beta lactamase and tetracycline resistance genes in Escherichia coli isolated from urinary tract infections in women in Tabriz city. In this cross-sectional descriptive study, 40 E.coli samples isolated from women with UTI were tested for determining the antibiotic resistance pattern as recommended by the Clinical Laboratory Standards Institute (CLSI) using disk diffusion method. Then, PCR method was performed for identification of tetA, tetB, tetC, TEM and SHV genes. The most antibiotic resistance was related to ampicillin and cephalexin (100%) and the least antibiotic resistance was related to tetracycline (25%). The frequency of tetA, tetB, tetC, TEM and SHV genes was 5%, 0%, 0%, 30% and 0%, respectively. One E.coli isolate (2.5%) harbored TEM and tetA genes simultaneously. Regarding the high frequency of resistance to beta lactam and cephalosporin antibiotics, precise antibiogram testing is highly recommended before any antibiotic prescription in cases of UTI.

Probiotics are living dietary supplements that exert their health benefits by improving the intestinal microbial balance in the host. lactic acid bacteria are the most common type of bacteria that have been identified as probiotics. This study isolated lactic acid bacteria from the traditional yogurt, dooghd and, curd of Mazandaran Province in Iran and investigated their probiotic potency and antimicrobial effect on Pseudomonas aeruginosa. lactic acid bacteria were isolated by phenotypic and biochemical tests of acid resistance and bile salt tolerance tests, and their primary probiotic index was evaluated. Tube dilution and turbidimetry were used to determine the minimum inhibitory concentration of antimicrobial substances. The inhibitory effect of the isolated bacteria on P. aeruginosa was investigated by the disk-diffusion agar method. The non-growth halo diameter was measured around the disk. In order to reduce errors, each test was repeated at least three times, and the mean non-growth halo diameter was measured on Mueller-Hinton agar and its antagonistic effect was investigated. The findings showed that adding a lactobacillus dose increases its inhibitory effects. The Lactobacillus plantarum were identified using specific primer pairs of the 16S rRNA gene, the established specific band, and PCR product sequencing. Rec A gene PCR was performed for differentiating the members of this group using specific primers and five L. plantarum strains were identified. According to the results of this study, lactobacilli were well able to inhibit the growth of pathogenetic strains. In this study, L. plantarum had an inhibitory effect on

Antibiotic-resistance is becoming an increasingly important concern. Resistant bacteria like Pseudomonas aeruginosa have different strategies while encountering either the immune system or antibiotics. As an example biofilm formation or quorum sensing can be mentioned as bacterial mechanisms to gain resistance. Therefore, it is crucial to explore novel compounds that might disrupt biofilm production especially using organic and plant-based compounds. Citrus limon essential oil has been used against multiple types of microorganisms in traditional medicine. The purpose of this study is to investigate the effect of this essential oil on P. aeruginosa biofilm formation. The inhibition of biofilm was measured using a micro-dilution method, staining the biofilm that has been formed and determining the minimum inhibitory concentration that proved effective. Then, via molecular docking software, the ligands more likely to interact with biofilm proteins were predicted. Our results suggest that after multiple determinations of minimum inhibitory concentration, the lowest effective dose was in concentrations between 100 µg/ml to around 450 µg/ml. Furthermore, molecular docking results demonstrated that between all the essential oil ligands, the top three were geranyl acetate, α-terpineol, and β-bisabolene. To sum up, Citrus limon essential oil showed promising anti-quorum sensing properties and it can be considered as a source of antimicrobial formulation.

HCV with millions of patients is one of the leading causes of liver cell cancer and liver cirrhosis. Based on the nucleotide differences, HCV has several types that play an important role in response to treatment. this study aims to develop a fast and accurate way to identify the most common genotypes of this virus in Iran based on the 5´-UTR region using probe hybridization method. In this study, 45 positive serum samples with a Titer of more than 1000U/mL, all of which were infected with genotypes 1a and 3a, were prepared from Golestan hospital. After designing and synthesizing the primers and probes, the system hybridization of the probe and the extraction of viral RNA with High Pure RNA Viral Extraction kit (Roche, Germany) the reaction optimization was performed. The results of the resulting genotyping were then compared with the initial results of the samples. The results obtained on the device showed that genotypes 1a and 3a have different melting point peaks with a difference of about 2 degrees. Also, the results of the initial genotyping, which was based on the sequence determination of the 5´-UTR region, are consistent with the results obtained in this study. Although the hybridization method of the probe developed in this study is not perfect and is not able to identify 7 types of HCV, but despite the high frequency of 1a and 3a Genotypes in Iran (about 90%) and the speed of reaction and its single-stage can be Use it for initial screening.

Many pesticides enter aquatic ecosystem after use and act as environmental pollutants. Changes in the biochemical parameters of fish blood serum can be considered as a suitable factor for detecting the effects of toxicity and determining the physiological status of fish exposed to pesticides. Lactic acid bacteria are also the most common types of bacteria present in the digestive tract of fish which provide substantial advantages for them. The objective of this research was to investigate the influence of Acetamiprid pesticide on blood factors, protein total and lactobacilli in the intestines of the Cyprinus Carpio. For this purpose, Cyprinus Carpio were exposed to 17, 34, 56, 85 and 113 micrograms per liter of Acetamiprid pesticide for 35 days and its effect on protein, red blood cell, hemoglobin, hematocrit, white blood cell and lymphocyte were studied. The results of biochemical studies revealed that after 35 days, the levels of red blood cells, hemoglobin, hematocrit, white blood cells, and lymphocytes in fish blood significantly decreased. However, there was a remarkable increase in the total blood protein compared to the control sample. Also, after separating the G + bacilli from the intestine of the fish and examining its anti biogram with different doses of Acetamiprid, the growth of lactose bacilli was not observed in all doses. Due to the effect of Acetamiprid on blood biochemical parameters and intestinal bacilli, it seems that the use of this pesticide can detrimentally affect the survival of Cyprinus Carpio.

According to the vast widespread drug resistance among pathogenic microorganisms and the side effects of many chemical drugs, research on novel antimicrobial compounds is urgently needed. Some herbs have been shown to have antimicrobial properties and can be used to produce antimicrobial drugs. In this study, different extracts effects of Teucrium orientale was practiced on several pathogenic bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis, Salmonella typhimurium, Staphylococcus expidermidis). The plant specimens were dried and powdered after transferring to the laboratory and final approval. Extraction was performed using methanol and water solvents and then ethyl acetate, diethyl ether and chloroform fractions using standard methods. The extracts were kept in standard conditions after determination of net weight until the continuation of monitoring. Serial concentrations of each extract and fraction were prepared in appropriate solvent for microbial tests and then their antibacterial activity was performed according to standard agar diffusion method and mean diameter of growth zone was recorded as antimicrobial activity. Pseudomonas aeruginosa showed the highest resistance to different concentrations of the extracts according to obtained results. The highest sensitivity was observed in B. subtilis at concentration of 50 mg / ml ethyl acetate extract with 25.9 mm diameter of growth zone. The results of this study have shown that the extract of T. orientale has the ability to treat microbial infections in humans. Further studies and identification of its constituents are essential for the use of this plant as a drug.

Bacteriocins are antimicrobial proteins, which show antagonistic effects on pathogenic bacteria. The most important problems of bacteriocins are low stability and specific antibacterial activities. Using the antibacterial activity of nanoparticles in combination with bacteriocins is a new strategy against pathogenic bacteria. This study aimed to investigate the combined effects of iron oxide nanoparticles (IONPs) and bacteriocins produced by Lactobacillus casei ATCC 39392 against selected foodborne pathogens. Iron oxide nanoparticles (IONPs) were synthesized by hydrothermal method and characterized using a field-emission scanning electron microscope, transmission electron microscope, and dynamic light scattering analysis. Minimum inhibitory concentration and antibacterial activity of bacteriocins produced by L. casei ATCC 39392 alone, and in the combination of (IONPs) evaluated against selected foodborne pathogens including; Listeria monocytogenes PTCC1294, Bacillus cereus PTCC1857, Staphylococcus aureus PTCC1917 and, Escherichia coli PTCC1276 using checkerboard assay method. The obtained results showed that bacteriocin produced by L. casei ATCC 39392 combined with (IONPs) showed a fully synergistic effect on S. aureus 1917 and E. coli PTCC 1276 with fractional inhibitory concentration index (FIC) values of 0.3 and 0.4, respectively. The FIC indexes for L. monocytogenes PTCC1294 and B. cereus PTCC1857 were 0.9 (additive) and 1.5 (indifferent), respectively. Therefore, it concluded that using a combination of nanoparticles with bacteriocins has a promising candidate for the prevention of foodborne pathogens in food industries.

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a major concern all over the world. There is currently no proven vaccine and specific treatment to be effective for SARS-CoV-2 infection. Convalescent plasma obtained from patients who have recently recovered from infection has been used as a therapeutic intervention in previous coronavirus-related pandemics including SARS-CoV, MERS-CoV, and now COVID-19. The presence of neutralizing antibodies which specifically recognize SARS-CoV-2 are thought to mediate antiviral effects before patient develop their own humoral immune responses leading to cytokine storm and disease severity. In this review, we have summarized existing literature on convalescent plasma for the treatment of MERS-CoV, SARS-CoV, and COVID-19. Data from studies using convalescent plasma in COVID-19 suggest clinical improvements such as reduced viral load, oxygen requirement, and radiographic resolution. Although randomized clinical trials describing the benefit of convalescent plasma in COVID-19 are limited but these studies point to better outcomes of convalescent plasma treatment when administered earlier in the course of the disease. However, more precise randomized trials are needed to investigate different indications such as time of plasma administration and/or combination with other antiviral treatments.