International Journal of Molecular and Clinical Microbiology
Volume:4 Issue: 1, Winter and Spring 2014

Approximately all sequenced archaeal and half of eubacterial genomes have some sort of adaptive immune system, which enables them to target and cleave invading foreign genetic elements by an RNAi-like pathway. CRISPR–Cas (clustered regularly interspaced short palindromic repeats–CRISPR-associated proteins) systems consist of the CRISPR loci with multiple copies of a short repeat sequence separated by variable sequences with similar size that are derived from invaders and cas genes encode proteins involved in RNA binding, endo- and exo-nucleases, helicases, and polymerases activities. There are three main types (I, II and III) of CRISPR/Cas systems. All systems function in three distinct stages: (1) adaptation, (2) crRNA biogenesis, and (3) interference. This review focuses on the features and mechanisms of the CRISPR-Cas systems and current finding about them.

Sagebrush genus (Artemisia scoparia) is the one of the most important genus of Asteraceae family. It has numerous values because of medicine properties. Sagebrush genus has numerous application in traditional medicine from ancient times. In this research, the isolation and identification of essential oil and antibacterial activity of Artemisia scoparia have been studied. Samples were collected from the region of Baladeh, Noor, Mazandaran, Iran in middle of June 2013. The essential oil derivation was extracted after drying plant under shadow by Hydro-distillation method using Clevenger apparatus. Isolation and identification of essential components was done by GC-MS. Antibacterial activities of essential oil were assessed by diffusion disc method. Four bacteria used in this research were Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Salmonella typhimurium apparatus. Isolation and identification of essential components was done by GC-MS. Antibacterial activities of essential oil were assessed by diffusion disc method. Four bacteria used in this research were Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Salmonella typhimurium. The results showed that essential oil of Artemisia scoparia in both broth method microdilution and disc diffusion, had the most inhibiton diameter zone in Staphylococcus aureus than Staphylococcus epidermidis. Among negative gram bacterias, E.coli had inhibition diameter zone of higher in disc diffusion method. E. coli with the most MIC (Minimum Inhibitory Concentration) was the most resistant bacteria than essential oil of Artemisia scoparia. According to this results, essential oil of Artemisia scoparia can be used as a protector combination, natural flavoring in food.

Enterococci, as the major cause of nosocomial infections, have been shown to have an increase in drug resistance during the past two decades. The Entrococcal emergence of Vancomycin-resistant is very important nowadays. The purpose of this study was to determine the drug sensitivity of Enterococcus faecalis and Enterococcus faecium species against Vancomycin, Tetracycline, Gentamicin, Erythromycin and the presence of Van A / B genes in resistant Enterococci to Vancomycin. A total of 189 samples, including urine, blood, wound and stool were collected from patients referred to Masoud Medical laboratory in Tehran, Iran, during years 2011-2012. Strains of Enterococci were identified by standard methods and antibiotic susceptibility testing was performed by disk diffusion according to standard methods (CLSI). The test was carried out on the samples resistant to Vancomycin for determining MIC levels. The frequencies of VanA and VanB were studied by using of PCR. A total of 89 Enterococcus were isolated in this study. In this study, 89 Enterococcus were obtained, of which 8 were resistant to Vancomycin based on the disk diffusion method. All Vancomycin resistant isolates showed VanA gene, while none of them (0%) carried VanB gene. The results obtained by this study indicated that Vancomycin-resistant Enterococci isolates did not commonly carry the VanA gene. However, VanA gene was fairly frequent as it was detected in 8 strains, while VanB gene was found in none of the strains.

The frequency of fungal infections in immunocompromised patients, particularly by Candida species, has increased in recent years. Colonization by Candida species in respiratory tract in susceptible hosts may play an important role to precede disseminated candidiasis. This study was designed to identify Candida species from bronchoalveolar lavage (BAL) samples and determination of antifungal susceptibility of isolates to Ketoconazole, Clotrimazole, Fluconazole and Nystatin by disk diffusion method. Sampling was conducted between from 2011 to 2014 years. Three hundred and eighty four patients who were suspected to invasive fungal infections were enrolled in the study. Clinical specimens were studied for direct microscopic examination and culture. The antifungal activity test for Candida species isolated from BAL samples was performed by using disk diffusion, according to CLSI documents M44-A2. Eighty seven (%22.66) patients showed the symptoms, signs and predisposing factors for pulmonary fungal infections. The isolated species were identified as follows: C.albicans, 31 (67.39%); C.glabrata, 9 (19.56 %); C.krusei, 3 (6.5%); C.parapsilosis, 2 (4.3%); and C.tropicalis, 1 2.25%). In this study, resistance to antifungal agents were seen to Ketoconazole, 2 4.38%), Clotrimazole 1 (2.17%) and Fluconazole, 4 (8.69%). Determination of antifungal sensitivity of the isolated yeast species should be the basis of rational and successful therapy.

Halophilic bacteria grow over a wide range of salt concentrations. In this study we aimed to isolate and screen out the halophilic bacteria and to determine their activity for production of the bioactive compounds. A total of 50 water, sediments and soil samples were collected from Maharlu salt lake in southern region of Fars-Iran and subjected for isolation of the bioactive compound producing Halophilic bacteria. The results obtained indicated that out of all isolates, three strains could produce the bioactive compounds. The isolates were molecular (16SrRNA) identified as Bacillus licheniformis, Bacillus subtilis and Bacterium Culaeen. Furthermore, structural analysis of the bioactive compounds was carried out in order to achieve maximum information concerning to them. The results obtained illustrated the existence of glycoprotein in all the bioactive compounds. Although, Staphylococcus aureus, Aspergillusniger and Mucor…. were sensitive to all the bioactive compounds, Pseudomonas aeruginosa, Escherichia coli and Bacillus cereus were resistant to them. In addition, the bioactive compound producing isolated strains by Bacillus licheniformis and Bacillus subtilis showed antifungal activity against Aspergillusniger and mucor sp. In total, our finding illustrated that the maharlu salt lake might be considered a source of halophilic bacteria with potent activity for production of the bioactive compounds. In addition, isolation and characterization of these compounds culminate in the achievement of the new drugs.

Cladophora and Enteromorpha are the filamentous green-algal genuses that have a widespread distribution in Caspian Sea Coast. The aim of this study was to assess the antimicrobial activities of Cladophora and Enteromorpha in South of Caspian Sea. Antibacterial activities of hydroalcoholic extracts of five different gram negative and positive bacteria including Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Salmonella typhimurium, Proteus mirabilis were investigated. The extract was primarily screened for their possible antibacterial effects using disc diffusion methods. The potential antibacterial activities at different concentrations of the extract were elucidated. The extracts of Cladophora and Enteromorpha displayed variable degrees of antimicrobial activities on different bacteria. Among gram positive bacteria the Staphylococcus aureus (with wider zones of inhibition) was found to be more sensitive than Bacillus subtilis and among the gram negative Salmonella enteritidis was found to be more resistant than Pseudomonas aeruginosa in the extract of Cladophora glomerata. On the other hand, in the extract of Cladophora glomerata, the Staphylococcus aureus was found to be more sensitive among gram positive bacteria. In the extract of Enteromorpha intestinalis, the Bacillus subtilis was found to be more sensitive among gram positive bacteria. In general, gram negative bacteria were more resistant than gram positive bacteria. Studies by other researchers revealed the same type of results. The Pseudomonas aeruginosa was found to be the most resistant among all bacteria (without zones of inhibition). Our findings suggest that the possibility of using the Cladophora glomerata and Enteromorpha intestinalis as the novel sources of natural antimicrobial and antioxidant agents for pharmaceutical industries.

Lactic acid bacteria (LAB) are gram positive and non- spore forming bacteria that can produce some special substances for growth inhibition of pathogenic, nonpathogenic and food spoilage bacteria. The aim of this study was to determine the inhibitory effects of Lactobacillus acidophilus PTCC1643 (DSM 20079) and Lactobacillus plantarum PTCC 1058 (ATCC 8014) cultural supernatants against urinary tract infections (UTI) agents, including Klebsiella pneumoniae, Enterobacter aerogenes, Escherichia coli and Lactobacilli spp in MRS Broth. Selective culture media and biochemical tests were used for UTI bacteria isolation. Inhibitory effects were evaluated using well diffusion agar and the inhibitory zone diameters were measured after overnight incubation at 35-37C. The highest inhibitory effect were obtained using L. plantarum PTCC 1058 cultural supernatantagainst E.coli and the lowest one using L.acidophilus PTCC 1643 cultural supernatant against K.pneumoniae. These Lactobacilli spp.were showed inhibitory effects on all of the isolated bacteria. Totally, L.plantarum PTCC 1058 showed inhibitory activity more than L.acidophilus PTCC 1058. The findings of this study showed that Lactobacilli spp. as a capable candidate for producing antibacterial compounds and using them for treatment and industrial usage.

Vulvovaginal candidiasis is caused by the increasing number of Candida species as normal flora in the vagina. To assess the transmission rout as well as to determine the suitable antifungal drugs for treatment, the exact identification of Candida species is crucial. Therefore, earlier detection of infection allows quick initiation of antifungal therapy with a greater probability for improved survival. The aim of this study was to evaluate the identification of Candida albicans using restriction fragment length polymorphism (RFLP) and to determine the in vitro susceptibility against four antifungal drugs. In this study, 1 clinical samples were obtained from the patients with suspected Vulvovaginal Candidiasis. Early identification of the grown yeasts was performed by physiological tests. Universal primers used to amplify the internal transcribe spacer region. Subsequent restriction enzyme analysis of PCR products was done using Msp1 and Bln1 which allows us to identify the most medically important C.albicans and C.dubliniensis. Antifungal susceptibility test was performed according to the CLSI M27-A3 broth microdilution method, and minimal inhibitory concentrations were determined for Nystatin, Fluconazole, Amphotericin B and Itraconazole. Fifty eight of 100 Candida species were isolated from suspected samples in which 36 isolates were identified as Candida albicans/ C.dubliniensis by using PCR-RFLP method as well as physiological test. Among them, only 1 isolate was identified as C.dubliniensis. All C.albicans isolates were susceptible to Amphotericin B and Nystatin. However, 5 C.albicans isolates were resistant to Fluconazole with MICs ≥ 64 μ g/ml (13.89%) and 4 isolates were resistant to Itraconazole with MICs ≥ 1 μ g/ml 11.11%). C.albicans is still the predominant species causing Candida-related infections. Nevertheless, the number of isolated yeasts from other species is growing gradually. Identification of Candida at species level is very important due to the increasing trend in the number of Candida isolates which have high MICs against antifungal agents.

The use of herbal products in the prevention of the growth of pathogens have been widely studied. Problems in the treatment of infections caused by resistant strains of fungi are indicator of the need for a more in-detailed study of herbal remedies. Artemisia aucheri is used as a medicinal plant with anti-microbial properties, and as an astringent. Plant tissue culture is an important technique for the production of secondary metabolites. The aqueous and methanol extracts (AE and ME) were prepared from the resulting callus. In the agar well diffusion method in a concentration of 2500 mg/ml of AE, the growth inhibition zone diameter (IZD) of clinical isolates of C.albicans was greater than that of fluconazole and both standard strains of C.albicans (PTCC 1167 , 5027) was greater than the positive control. The results of the effect of AE showed that has the greatest effect on C.albicans 1167. The mean growth IZD of AE at the concentrations of 1000, 1500, and 2000 (mg ml-1) were 5, 10, and 18 mm, respectively. Based on the results of this study, the concentration of 1000 (mg ml-1) callus AE had no significant effect on any of the strains. The results of the anticandidal effect extracts showed that the ME has the greatest effect on the standard strains. The AE showed significant antifungal effects against the tested clinical isolates. The results obtained from the tube dilution method confirmed the above results. Different concentrations of extracts showed that with increasing concentration the anticandidal activity also increased.

Human immunodeficiency virus (HIV) infection is the major problem in the world. Nowadays, new anti-retroviral drugs are extracted from medicinal plants, make an important role to supersede synthetic drugs with different side effects. In this study, we studied the Salix aegyptiaca L extract, Iranian herb, as an anti-HIV drug with anti-retroviral effects. We used a single cycle replicable (SCR) HIV-1 system by co-transfection of HEK 293T with pmzNL4-3, psPAX2 and pM2G.2. Cytotoxicity and cytopathic protection assay were performed by XTT method. Inhibition of p24 Ag production level assay was done using quantitative enzyme linked immunosorbent assay (ELISA). Salix aegyptiaca L inhibited HIV-1 induced CPE in HELA cells with SI value of 22.2. Finally, we use informatics analysis such as Gaussian, Hyper Chem , HF and B3LYP methods and 6-31G, 6-31G** and 6-311G** basis sets. These results suggest that Salix aegyptiaca L has potent anti-HIV activity and may be a promising candidate for AIDS.