International Journal of Molecular and Clinical Microbiology
Volume:6 Issue: 2, Summer and Autumn 2016

Staphylococcus aureus carrying PVL gene remain major health problem associated with highly virulent infections. Characterization of such gene is important to know the impact and the functional significance of nucleotide variations. PCR and standard sequencing were performed for twelve Sudanese strains from different sources. Protein structures prediction, modeling and physiochemical analysis were done to analyze genetic variation in PVL. Single nucleotide polymorphism at position 610 (A / G) of lukS-PV was detected in all tested isolates resulted in nonsynonymous mutation in the amino acid sequence at position 204 (N / D). Using molecular and bioinformatics tools the detected novel mutation in lukS-PV may have a diagnostic functional significance.

Honey is a popular food product produced by honey bees that it is a well-known antimicrobial and antioxidant activity. Floral origin of honey plays an important role on its biological properties.This research was carried out to evaluate the antibacterial and antioxidant activity of four sample honey with different floral origin collected from the bee hive in the Golestan province in north of Iran. Evaluation of antibacterial activity against four pathogenic bacteria was performed by agar well diffusion method. Maple honey with diameter of inhibition zone as 23.33,22,14.33 and 13.33mm against Shigella dysenteriae, Staphylococcus aureus , Bacillus cereus and Escherichia coli respectively showed significant antibacterial effects. MIC and MBC of honey samples were determined by broth macrodilution tube method. The total phenol content (TPC) and the total flavonoid content (TFC) of honey samples was determined by Folin–Ciocalteu reagent and with aluminum chloride method respectively. Also to assess potential antioxidant activity of honey samples was used from reaction with 1,1 diphenyl-2-picrylhydrazyl (DPPH) radical. MIC and MBC values of obtained for linden, maple and astragalus honeys were in the range of %6.25-25% (V/V). The highest values of TPC, TFC and DPPH radical scavenging activity was related to linden, citrus and maple honeys respectively. In this study was demonstrated antibacterial and antioxidant activity of honey samples especially linden honey. Statistical analysis showed that the total phenolic content correlated with its antioxidant activity (P

This study was conducted in acompletely randomized block design with three replications using three concentrations of 107, 105, and 103cfu/ml of Azotobacter isolated from the rhizosphere of Karun varieties of barley (Az. salentris) and standard Az.chrococom along with control (zero concentration of bacteria). The aim of this study was to study the reactions of barley plantin response to inoculation by mentioned bacteria in the form of infected separate inoculation and non-inoculated seeds as a control. For isolation the number of mentioned bacteria, Karun variety of barley in desert was cultivated in the mannitol broth environment, and macroscopic and microscopic characteristics of bacterial colonies were evaluated. Finally, using gene 16Sr DNA, isolated variety was identified molecularly. At the end of plant growth, important traits such as percent of germination, total protein level, and activity of antioxidant enzymes of catalase and peroxide were measured from the desired plant and they were analyzed statistically. After 18 days, results showed that the concentration of 107, 105, 103cfu / ml of Azotobacter isolated from the rhizosphereKarun variety of barley plant in the desert (Az. salentris) increased the activity of antioxidant enzymes, total protein, and percentage of germination compared with control. In addition, different concentrations of Azotobacter isolated from the rhizosphere of barley plant (Az. salentris) showed higher and significant impact on catalase activity, total protein level, and percentage of Karun variety of barley germination compared with standard Az.chrococom.

The aim of this study was to assess the prevalence of ESBL-producing E. coli in agricultural fields of Gorgan district, Golestan province. Soil samples were collected from 20 agricultural fields, half of them treated with chemical fertilizers and the rest with bovine manure. Two samples, from surface and a depth of 15cm, were taken. After enrichment and culture onto MacConkey agar, Pink colored colonies were examined for Escherichia coli. The cefotaxime resistant E. coli were examined by phenotypic confirmatory tests. Then, antibiotic susceptibility of the confirmed ESBL-producing E. coli strains was determined. The results of this study showed that the prevalence of E. coli in the manure-amended soils were higher than the soils enriched with chemical fertilizers. Moreover, E. coli strains in the depth samples were more than the surface samples. About %53.1 of the strains isolated from the manure-amended soils were resistant to Cefotaxime and the %43 of them were positive for ESBL. Meanwhile, %33.3 of the strains isolated from the soils treated with chemical fertilizers were resistant to Cefotaxime in which %75 of them were ESBL producers. The highest resistance rate was observed against amoxicillin in all the ESBL-producing isolates. The results of this study showed that the use of animal manure may increases the dissemination of the antibiotic resistant bacteria to the soil. This may transfer antibiotic-resistant genes to other bacteria, causing spreading of these genes in the environment.

Staphylococcus aureus, as one of the main agentsfor hospital infections,is considered as highly important because they show resistance to a wide range of antibiotics.Resistance to selective antibiotics such as vancomycin is a serious problemin the medical community; thus it seems rational to use alternative substances for treating these bacteria.The aim of this study isto investigate the prevalence of resistance to vancomycin in clinical isolates of Staphylococcus aureus as well as theantimicrobial effects of zinc oxidenanoparticles on them. In this study, 70 samples of wound, boil, abscess and urine were isolated.Staphylococcus aureus strains resistant to vancomycin were then identified through routine laboratory tests using Broth Microdilution test. The antibacterial effect of ZnO nanoparticles(20 nanometer) was investigated at concentrations of 100,50,25,12.5 and 6.25 mg/ml using Agar well diffusion method over strains resistant to vancomycin. From the total of 70 samples, 30 samples were identified as Staphylococcus aureus out of which 23.3% showed resistance to vancomycin. During this study it was found that ZnO nanoparticles in concentrations of 50 and 100 mg/ml have a good antibacterial effect and can be a good alternative for controlling Staphylococcus aureus resistant to vancomycin. Considering the increasing trend in drug resistance, the growth of pathogenic bacteria can be inhibited by increasing the concentration of zinc oxide nanoparticles.

Acute gastroenteritis (AGE) has a great impact on children less than five years of age, producing high levels of morbidity and mortality. Worldwide, AGE is mainly related to viruses, mainly rotavirus but human adenovirus (HAdV) in particular as an important etiologic agent. Among HAdV species F, genotypes 40 and 41 are responsible for a high number of diarrhea cases, mainly in children under 2 years of age. Two hundred and fifty four fecal samples were analyzed using conventional PCR to detect and characterize enteric HAdV in children less than five years diagnosed with AGE and recruited between 2012 and 2013 through the Sentinel Surveillance Program from Bogota DC, Colombia. Fourteen samples (5.51%) were positive for HAdV. Species-specific detection showed one HAdV-A sample, four HAdV-B samples, two HAdV-D samples, two HAdV-E samples, and five HAdV-F samples. HAdV-F samples were subjected to conventional PCR in order to identify genotypes 40 and 41. All HAdV-F samples were genotype 40, except for one sample coinfected with both genotypes (40 and 41). Our results show that enteric HAdV are important agents in the etiology of AGE in children less than 5 years old. Moreover, the species-specific PCR analysis demonstrated that species other than HAdV- F which are tightly associated with respiratory tract disease, could infect and produce gastrointestinal tract disorders.

Antibiotic resistance is a phenomenon in which antibiotic used to treat bacteria becomes useless due to resistance mechanism. Increased drug resistance and occurrence of Multiple Drug Resistance in bacteria specificity nosocomial and Urinary Tract Infection bacteria has reduced the possibilities of treating these infectious diseases. Efflux pumps are one of the major mechanism of MDR in bacteria which effluxes out the drugs accumulated . Various MDR phenotypes that confer active protection against environmental toxic compounds by efflux mechanisms have been described in Enterobacteriaceae. The aim of this study was evaluation of efflux pumps in Uropathogenic Escherichia coli and Klebsiella pneumonia MDR isolates.
41 UPEC and 37 Klebsiella MDR strains that were isolated from urine samples and identified by biochemical tests were determined by disc diffusion method according to CLSI. The ETBr-agar cartwheel method with different concentrations of Ethidium bromide was used to assess the presence of efflux activity. Our results showed that among UPEC isolates 39%, 9.8% and 51.2% had High, moderate and no efflux activity. Among klebsiella pneumonia isolates 27%, 24.32% and 48.64 % had High , moderate and no activity, respectively. Also the frequency of UPEC bacteria with over expression of efflux pumps was 80% but for Klebsiella pneumonia isolates 52% was reported. UPEC isolates had more actively efflux pumps than Klebsiella isolates.Both bacterial isolates had ability to use efflux antibiotics out. The Et-Br cartwheel method could be used as a simple method for determining the phenotypic activity of efflux pump in UPEC and K. pneumoniae MDR isolates.

In modern medical processes, new antimicrobial drugs are being widely used in order to rapid and essential eradication of resistant bacterial strains. Broad-spectrum beta-lactamases are enzymes originated from mutations in the common plasmid genes mediators for beta-lactamases such as TEM-1, TEM-2, and SHV-1 are transferred among bacterial species. The genes coding the production of ESBL are often connected to other resistant genes causing resistance to drugs with broad spectrums. Therefore, there are different experimental techniques to detect ESBLs. This study aimed to investigate the presence of blaSHV and blaTEM genes coding beta-lactamase enzymes in E. coli isolated from Zarjob River in Gilan Province, their resistance to different antibiotics, and their stereotyping. In order to isolate and identify E. coli, 25 water samples were taken from Zarjob River and analyzed by MPN test and biochemical tests. Antibiotic sensitivity testing with Kirby-Bauer method, i.e. disk diffusion on 25 E. coli isolates, and also serotyping with agglutination on a slide were performed. To detect blaSHV and blaTEM genes in E. coli, PCR technique was used and all results were analyzed by using the software SPSS.Among the 25 E. coli isolates, 18 cases (72%) had the gene blaTEM and 15 cases (60%) had the gene blaSHV. The results of polyvalent antiserums serotyping were observed as Group I (O26, O55, O111), Group II (O88, O127), Group III (O44, O125, O128), and Group IV (O20, O114).

Two of the major factors that should be considered in leaves extraction are the solvent type and extraction method. In the current study, the effects of two solvents (Ethanol and Methanol) and two extraction methods (soaking and soxhlet) on phenolics and flavonoid contents, antibacterial and antiradical properties of extracts were investigated in a factorial experiment based on completely randomized block design. The analysis variance of results showed that the extract had significant effects on phenolic compounds and flavonoids (p≤0.05). The highest content of phenolics and flovonoids observed in methanolic extract obtained by soxhlet method. In the same way, the effects of pennyroyal extract on free radical scavenging indicated that the highest antiradical properties of extracts recorded in methanolic extract by soxhlet method (p≤0.05). The MIC and MBC experiments on gram positive (Staphylococcus aureus and Bacillus cereus) and gram negative (Escherichia coli and Pseudomonas aeruginosa) bacteria, indicated that all extracts showed antibacterial properties and the highest sensitivity observed in Bacillus cereus. Also, the means comparison of results showed that the highest antiradical and antibacterial properties were observed in methanolic extract obtained by soaking method. It can be concluded that methanol as a more polar solvent has better ability to extract phenolic compounds than ethanol. According to results, while the extraction by soxhlet apparatus showed higher efficiency than soaking, but the probable destruction of phenolics in soxhlet method caused lower antibacterial properties of obtained extracts in comparison with soaking method.