JOURNAL OF MICROBIAL WORLD
Year:2016 | Volume:9 | Issue:1 (26)|Papers Count:8

Background & Objectives: Uropathogenic Escherichia coli (UPEC) is one of the most common bacteria to cause urinary tract infection (UTI). No human vaccine against UTI has yet been developed. The aim of this study was to optimize the expression of recombinant PapG with Lactobacillus anchor protein AcmA in E. coli.Materials & Methods: The synthetic cloning vector, pEXA containing PapG.AcmA was purchased and subcloned into pET21a vector. The protein expression levels in Origami expression host (E. coli) were analyzed by SDS-PAGE gel and western blotting. Moreover, various concentrations of IPTG (Isopropyl Thiogalactopyranoside), the medium component and induction time was optimized for large scale expression of recombinant protein.Results: Based on results, optimum expression in large scale was occurred in 0.1mM IPTG and OD=3 optical density. The modified complex culture medium containing: glucose 6 g/I, K2HPO4 12.5 g/l, KH2PO4 2.3 g/l, Yeast Extract 20 g/l, tryptone 10 g/l were determined as optimal medium. OD 600nm=3.0 was determined as the best time for induction by IPTG at a concentration of 0.1 mM. The levels of the expression of the target protein was determined at OD600nm=5.5.Conclusion: Based on the result, we were able to do cloning and expression of PapG.AcmA. Addition of extra carbon source (glucose) to the complex medium caused a better PapG.AcmA recombinant protein expression. Finally, by purification of recombinant protein and evaluation of its immunogenicity, it can be used as a vaccine candidate against the urinary tract infection.

Background & Objectives: Helicobacter pylori is one of the most common pathogen bacteria in human being. Almost half of the population of the world are infected with this bacteria, and it has been known an important factor in gastrointestinal diseases such as; chronic gastritis, gastric ulcer and gastric cancer. Interleukin-27 is a pro-inflammatory cytokine expressed by a novel subset of CD4+Th cells, and it causes the occurrence and strengthening the inflammatory response. This study was aimed to analysis of association between IL-27 polymorphisms and clinical outcomes due to infection with H. pylori.Materials & Methods: A case-control study has been performed on 434 people 149 patient cases (100 gastritis and 49 ulcerative gastritis), 58 gastritis cases but H. pylori negative and 227 healthy controls. Genomic DNA was extracted and genotypes of IL-27 (-964 A/G) polymorphism were assessed through polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Finally the results were compared between these patient and control groups.Results: The frequency of A allele was higher in gastric patients (78.5%) in comparison with the control group (75.6%). However, these differences were not significant. In addition, the distributions of genotypes were not significantly different between the study groups.Conclusion: These results suggest that IL-27 (rs964 A/G) polymorphism gene is not directly involved as a genetic risk factor in the predisposition to H. pylori.

Background & Objectives: The incidence of candidiasis has been increased in immune compromised patients. Biofilm formation is counted as the main mechanisms of antibiotic resistance in Candida albicans. The aim of this study was to investigate the effects extractions of Lamiaceae family in quantification of HWP1 gene expression responsible for inhibition of biofilm formation in C. albicans.Materials & Methods: In this cross- sectional study, the antifungal effect of aqueous and ethanolic extractions of leaf, stem and root of Mentha spicata, Mentha pulegium and Thymus vulgar, commercially purchased from Yasooj, was analyzed against C. albicans using disc diffusion and broth microdilution methods. The crystal violet colorimetric method, morphological response and expression pattern of hypha-specific gene HWP1 were carried out to investigate the biofilm-inhibitory properties of the best plant extract tested.Results: The data indicated that aqueous root extracts of Thymus vulgaris exhibits high antifungal activity against C. albicans. The aqueous extract of Thymus vulgaris root-treated cells exhibited significant reduction in biofilm growth. In addition, morphological observation of extract of Thymus vulgaris and fluconazole-treated cells confirmed decreases in fungal reproduction. Finally, aqueous root extractions of Thymus vulgaris was shown to down-regulate the expression of HWP1.Conclusion: The results of this study showed the possible molecular mechanism of effects of aqueous root extraction of Thymus vulgaris root in C. albicans on biofilm formation.

Background & Objectives: Staphylococcus aureus is one of the most important nosocomial infection agent and now methicillin-resistant S. aureus have spread. Also, panton-valentin leukocidin is one of important virulence factors in S. aureus. The study was aimed to evaluate the antibiotic resistant, frequency methicillin resistant and panton- valentin leukocidin genes in clinical S. aureus isolates from hospitals of Rasht, Iran.Materials & Methods: This cross-sectional study was carried out on 250 clinical samples collected from hospitals of Rasht during one year (2013-2014). The S. aureus isolates were identified by microbiological methods. Antibiotic sensitivity was performed by CSLI method using disk diffusion method. In addition, the presence of methicillin resistant (mecA) and panton-valentin leukocidin (pvl) genes were evaluated using polymerase chain reaction (PCR).Results: Totally, 50 S. aureus isolates were recovered. The results of antibiotic susceptibility tests showed that 34 out of 50 S. aureus isolates (68%) were resistant to methicillin. In addition, the prevalence of mecA and pvl gene among isolates were 60% (30 isolates) and 20% (10 isolates), respectively.Conclusion: This study showed increased resistance to different antibiotics in S. aureus that is a serious warning to the treatment of infections caused by this bacterium in the region.

Background & Objectives: Urinary tract infection (UTI) is a common bacterial infection in humans. Uropathogenic Escherichia coli (UPEC) strains are one of the etiologic reason for UTIs. The purpose of this study is evaluation of bacterial resistance to commonly used antibiotics and the prevalence of papaA and papC genes among uropathogenic E. coli.Materials & Methods: This cross-sectional study was carried out on 150 isolates E. coli collected from patients with UTIs referred to Imam Khomeini Hospital in Boroujerd. Antimicrobial susceptibility test was performed for all isolates against 13 antibiotics according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Then, prevalence of papA and papC genes was examined by PCR method.Results: The highest and lowest rates of antibiotic resistance belonged to ampicillin 127 (84.7%) and nitrofurantoin (3.5%). Also, the prevalence of papA and papC genes was 32 (21.3%) and 72 (48%), respectively.Conclusion: These results shows increases in the antibiotic resistance in pathogen E. coli and high levels of pap operon in these strains. Based on these results, further investigations on the bacterial virulence and the antimicrobial resistance patterns can improve the treatment of urinary infections.

Background & Objectives: Salmonella is a member of Enterobacteriaceae. Dairy products, such as cheese, are one of the environmental sources of these bacteria. This study was performed to isolate Salmonella enteritidis collected from traditional cheese produced in Chaharmahal va Bakhtiari province, and also to study the frequency of associated gene with drug resistance. Materials & Methods: In this cross-sectional study, 100 samples of traditional cheese were collected from Chaharmahal va Bakhtiari province. Bacterial culture and biochemical tests were used to isolate and identify Salmonella strains. PCR assay was used for final diagnosis of Salmonella genus and direct detection of S. Enteritidis, and also to study the frequency of tetA, tetB, tetC, cat3 and floR genes. The Kirby-Bauer disk diffusion method was used to perform the antibiogram tests.Results: Overall, 32 (32%) cases out of 100 samples were detected as Salmonella contamination. Of these, 10% (31.25 cases) of samples belonged to S. enteritidis. The highest frequency of antibiotic gene resistant belonged to tetC (70%). The highest antibiotic resistance (100%) was related to tetracycline and the highest sensitivity (100%) was related to cefotaxime.Conclusion: The results of present study showed that S. enteritidis carry high frequencies of antibiotic resistance genes. The presence of high resistance to chloramphenicol and tetracycline can be because of the presence of these genes.

Background & Objectives: Since the wound infections caused by gram positive and negative bacteria are very common, application of Nanocrystalline silver in wound healing bands is recently of one of points of research interests. The epithelization effect and control of wound infection are the most important factors for selection of disinfecting factors in these bands. This study was performed to produce nanocrystalline silver bands and to investigate their efficiency on control of selected gram positive and negative bacteria.Materials & Methods: In this study, silver nanocrystalline dressing was produced using nylon dressing and silver ions. Thereafter, we evaluate its antibacterial effect against Staphylococcus aureus and Escherichia coli. The experiments were designed based on Taguchi method for investigation different parameters on antimicrobial effect of silver dressing.Results: The silver dressing showed an impressive effect on inhibition of the growth of mentioned bacteria and leads to the inhibition zone diameter of 5.5 cm around the dressing pieces. AgNO3 was the most important parameter in determination of the antimicrobial effect of silver dressing (approximately 65% efficiency).Conclusion: Silver nanocrystalline dressing was effective on inhibition of microorganisms growth. Furthermore, application of Taguchi method was highly effective in optimization process of this investigation.

The first step to choose a strain as probiotic is capability for the bacteria to adhere to mucosal adhesion due to increase the prevention of the adherence of pathogenic bacteria, and the secretion of antimicrobial agents, which produce an appropriate condition of microbial growth. This study was aimed to evaluate the adherence ability of Lactobacilus casei to Hep-2 cell line. First, the HEp-2 cells were grown in RPMI medium containing fetal calf serum and antibiotics. The defined numbers of probiotic bacteria grown in MRS broth were added to the HEp-2 cell. Then, the cells were washed after attachment of bacteria to the plates. Thereafter, the cells were stained and fixed with histological methods. The adhesion ability of bacteria and the pattern of adhesion was observed under optical microscope. Our results showed that L. casei was able to adhere to oro- pharyngeal cell line. Also, the optimum time to test the ability was 3 hours. These results indicated that the probiotic bacterium L. casei is suitable for application in health products. Based on these results, we recommend application of L. casei in oral hygiene products.