فهرست مطالب

Medical Microbiology and Infectious Diseases - Volume:3 Issue: 1, Winter-Spring 2015

Journal of Medical Microbiology and Infectious Diseases
Volume:3 Issue: 1, Winter-Spring 2015

  • تاریخ انتشار: 1395/01/18
  • تعداد عناوین: 8
|
  • Ali Farahnak*, Fariba Amni, Taghi Golmohammadi, Mohammad Reza Eshraghian, Mohammad Bagher Molaei Rad Pages 1-5
    Introduction
    To determine an indicator for Triclabendazole (TCBZ) efficacy, Alanine aminotransferase (ALT) activity in Fasciola hepatica (Iranian isolate) parasite in presence and absence of TCBZ was evaluated by an in vitro cultivation method. Also, ALT enzyme activity between none and parasitized-infected sheep liver tissues was assessed.
    Method
    The sheep livers were collected and transferred immediately to the Department of Parasitology. Adult living parasites were recovered, washed and divided into two groups, treatment and control groups with 10 parasites in each. We added 15 μg TCBZ to the treatment group; then incubated both groups for 4 h at 37ºC. The parasites, infected and parasite free liver tissues were ground and homogenized by a Mortar and pestle, centrifuged, and supernatants were recovered. Protein concentration and ALT enzyme activity were measured in the supenatants.
    Results
    The results of ALT enzyme activity assay showed 0.03 U/ml/mg protein for treated F. hepatica and 0.01 U/ml/mg protein for untreated samples, the mean values of difference was not significant (p>0.05). The difference between ALT activity in none and parasitized-infected liver was not significant (p>0.05). However, two-sample T-test analysis showed higher ALT activity in treated and untreated parasite in comparison with none and parasitized-infected liver specimens (p
    Conclusion
    ALT activity cannot be considered as a useful marker for TCBZ efficacy in F. hepatica treatment. However, ALT enzyme showed comparable activities in parasite and its host liver tissue.
    Keywords: Alanine Aminotransferase, Fasciola hepatica, Egaten®, Triclabendazole, Liver
  • Darioush Gharibi, Mohammad Khosravi*, Zohreh Hosseini, Fatemeh Boroun, Seyedeh Kolsum Barzgar, Ali Forughi Far Pages 6-10
    Introduction
    Aloe Vera compounds have inhibitory activity on fungi, bacteria, and viruses. This study examines the antibacterial activity of A. Vera purified extracts including gel, boiled skin, boiled gel, and distilled extract against pathogenic bacteria, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Klebsiella pneumonia and Pseudomonas aeruginosa were elucidated.
    Method
    The bacterial strains were collected from veterinary hospital. Freshly collected A. vera leaves were used for the juice extraction of gel, skin and distilled extracts. Antibacterial effects of various A. Vera extracts were evaluated using broth microdilution method. The crude polysaccharides of boiled skin extract were purified by phenol method; and fractionated by anion exchange chromatography. For each bacterium, minimum inhibitory concentration of various A. Vera extracts was determined. The protein expression changes of treated bacteria were detected by SDS-PAGE electrophoresis.
    Results
    The distillate extract exhibited more antibacterial effects than other extracts. Out of seven-carbohydrate fractions of the skin extract, the fractions 6 and 7 had antibacterial effects on S. aureus and MRSA at 0.089 and 0.134 mg/ml, respectively; also fraction 5 showed antibacterial effects on MRSA at 0.113 mg/ml concentration. The protein profiles of these strains before and after treatment with A. Vera showed significant differences at 175, 60, 200 and 70 kDa protein bands of S. aureus, MRSA, P. aeruginosa and K. pneumonia, respectively.
    Conclusion
    This finding showed that the distillate extract despite the minimal amount of carbohydrate and protein was more efficient against both Gram-positive and Gram negative bacteria.
    Keywords: Aloe Vera, Extracts, Antibacterial
  • Samaneh Kazemi*, Mohammad Faezi, Ghasemi Pages 11-17
    Introduction
    Listeria monocytogenes is a serious concern for the food industry due to its high case fatality rate, widespread distribution, ability to survive a wide variety of food processing conditions, and the severity of the illness associated with this pathogen infection. The objective of this study was to determine the growth, cell morphology and biochemical characteristics of L. monocytogenes PTCC 1297 (Serotype 4a) under selected environmental stresses.
    Method
    The environmental stresses were acid stress (HCl, pH 2.0-6.0), alkaline stress (NaOH, pH 8.0-12.0), ethanol stress (5.0%-25.0% vol/vol), oxidative stress (H2O2, 0.06%-6.0% vol/vol), osmotic stress (NaCl and sucrose, 2.0%-30.0% wt/vol) and heat stress (40-60°C). All stresses were applied to the exponential phase bacteria whereas non-stressed exponential phase cells served as a control and the cells were allowed to grow for 24 h. For evaluating the growth of L. monocytogenes PTCC 1297 after inoculation procedure and exposure of cells to selected stresses we used colony count method. Scanning electron microscopy (SEM) was implemented to visualize the external appearance of the bacteria.
    Results
    According to the results, the bacteria at pH≤4 and pH≥10 achieved by HCl and, NaOH, respectively, died. Also, concentrations ethanol at ≥15% vol/vol, H2O2 ≥0.3% vol/vol, NaCl ≥14% wt/vol, and heat ≥50°C were lethal for the bacteria. Unlike other stresses, sucrose did not kill bacteria but decreased their growth. The phenotypical and biochemical characteristics of them changed when exposed to each stress.
    Conclusion
    Different doses of various stresses were either lethal or sub-lethal for this bacterium and lead to various changes in its characteristics.
    Keywords: Listeria monocytogenes, Cell Biology, Environment, Stress Physiological
  • Mahdi Salimi*, Mohamadreza Mahzonieh Pages 18-22
    Introduction
    The purpose of this study was formulation and preparation of a proper culture medium for Saccharomyces cerevisiae var. boulardii with molasses and animal serum.
    Methods
    A fully-crossed factorial design contain 5%, 10% and 20% of molasses (M) with 0, 1% and 5% animal serum (S) was used in this study. The pH of all culture medias were adjusted to 5.6 with acetic acid. The seed was consisted of 106 yeast particles which was added to culture media. The inoculated medias were incubated at 37°C for 48 h and the mean yeast counts was recorded.
    Results
    The mean of yeast counts for 5% M% S, 5% M% S, 5% M% S, 10% M% S, 10% M% S, 10% M% S, 20% M% S, 20% M% S, 20% M% S were 273333±20033, 228666±34428, 317333±170485, 499333±100425, 516000±38314, 514666±107057, 499333±100425, 516000±38314 and 514666±107057 particles in ml, respectively. In order to optimize culture medium, vitamins and vitamins in combination with minerals (at a concentration of 0.5%) were added to the optimal concentration of molasses and serum.
    Conclusion
    Statistical analysis with ANOVA test showed that the growth rate of yeast in 10% molasses plus 1% serum had a significant difference with 5% and 10% molasses in solid medium or 5% molasses supplemented with 1% serum (p
    Keywords: Serum, Molasses, Saccharomyces cerevisiae var. boulardii
  • Azam Fatahi*, Ali Ajami, Mojgan Bozorgzad, Shahram Nekoeian, Atefeh Khazeni Pages 23-28
    Introduction
    Awareness of the species of Shigella has particular importance in the way of dealing with an outbreak, controlling it, and treating patients. The purpose of this study was to use the Multiplex PCR method and comparison with the culture method to detect Shigella species, as well as analysing the antibiotic resistance pattern in its different species.
    Methods
    Simultaneously, the fecal samples of the patients with diarrhea and a sample from each patient in Cary-Blair medium were sent to the laboratory. Cultivation, serotyping, and antibiogram analysis were performed using the samples inoculated in the Cary-Blair medium. DNA extraction of the fecal samples and amplifying of invC, rfc, wbgZ, and rfpB genes were performed.
    Results
    Totally, 300 samples from the patients were analyzed, out of which 240 Shigella isolated (80%) were detected using the culture method and serotyping, and 260 Shigella isolated (86.6%) using the PCR method (Shigella flexneri (77%), Shigella sonnei (19.2%), and Shigella dysenteriae (3.8%)). 20 samples suspicious of Shigella were observed in the culture method but were not identified by serotyping. However, in the PCR assay, they were identified as S. flexneri (n=16) and S. sonnei (n=4). The resistance of Shigella isolated to Co-trimoxazole was observed to be (78.3%), Ceftriaxone (42.5%), Cefixime (42%), Azithromycin (40.7%), Ofloxacin (34.5%), Nalidixic acid (25 %), and Ciprofloxacin (16%).
    Conclusion
    Due to annual outbreaks of various Shigella species in the country, it is recommended that the Multiplex PCR method, be used along with culture method in laboratories to identify Shigella isolated. The antibiogram results showed increasing resistance of Shigella to the available antibiotics.
    Keywords: Shigella, Diarrhea, Antibiotics, Multiplex PCR
  • Hamid Staji*, Alfreda Tonelli, Taghi Zahraei Salehi, Mariangela Iorio, Federica Lopes Pages 29-34
    Introduction
    In Iran, invasive nontyphoidal Salmonella (iNTS) disease causes severe bacteremic illness among children
    Methods
    The microarray analysis enables identification of the strains that have the 90kb Salmonella typhimurium virulence plasmid, presence or absence of the Salmonella pathogenicity islands (SPIs), adherence factors and other virulence determinants. Twelve isolates of S. typhimurium obtained from faeces of children with gastroenteritis were analyzed by microarray technique.
    Results
    The virulence plasmid was present in 83.33% of isolates and all the isolates contained the SPI-4 and SPI-5. None of the strains had the cytolethal distending toxin, cdtB. All strains were positive for rck and mig-14. The adherence genes were present in all the strains in the range of 51.55% to 73.20% of the adherence genes interrogated in the microarray. Two strains were the least pathogenic S. typhimurium.
    Conclusion
    Microarray analysis proved to be a valuable tool in confirmation of serotyping results and genetic characterization of S. Typhimurium.
    Keywords: Salmonella typhimurium, Gastroenteritis, Microarray Analysis
  • Amir Hesam Nemati, Hamid Solgi, Farzam Vaziri, Fereshteh Shahcheraghi* Pages 35-37
    Introduction
    Stenotrophomonas maltophilia is a nosocomial multi drug resistant opportunistic pathogen which causes infections in vulnerable patients with cancer, cystic fibrosis and indwelling catheters.
    Methods
    45 clinical S. maltophilia isolates were collected from blood samples and identified by biochemical tests. Susceptibility to different antibiotics including co-trimoxazole, levofloxacin, minocycline, ticarcillin/clavulanic acid, chloramphenicol and ceftazidime were determined by disk diffusion and E-test methods.
    Results
    All isolates were resistant to ceftazidime and susceptible to co-trimoxazole and 11.1% were resistant to ticarcillin/clavulanic acid.
    Conclusion
    Ceftazidime as one of the extended spectrum β-lactams was the least effective antibiotic. Ticarcillin/clavulanic acid is one of the choosen antibiotics for S. maltophilia infections treatment. Here, we report tcarcillin/clavulanic acid resistance in S. maltophilia isolates for the first time in Iran.
    Keywords: Stenotrophomonas maltophilia, Antimicrobial susceptibility, Iran
  • Leila Tabatabaei Moradi, Anousheh Sharifan*, Kambiz Larijani Pages 38-43
    Introduction
    Essential oils are used as flavoring agents in various foods. Layer-by-Layer (LBL) technique is a method in which the material is dipped into a series of different solutions containing oppositely charged polyelectrolytes. The aim of this study is to investigate the effectiveness of a multilayered edible coating with an antimicrobial compound (Lemon and Peppermint) in enhancing the quality and shelf-life of rainbow trout (Oncorhynchus mykiss) during refrigerated storage (4 ± 1˚C) over a period of 16 days.
    Methods
    In this study, multilayered coating was used with two concentrations of Lemon (LEO) and Peppermint (PEO) essential oils (0.5 and 1%). Antibacterial effect of these treatments was evaluated by enumeration of bacteria in special culture media. The control and the coated fish samples were analyzed periodically for pH and microbiological (total viable count, psychrotrophic count, lactic acid bacteria, Enterobacteriaceae, and coliform) characteristics.
    Results
    The results obtained in this study demonstrate that multilayered coating in combination with Lemon and Peppermint essential oils can significantly decrease the number of bacteria and delay the spoilage of the samples (p
    Conclusion
    Multilayered edible coating with an antimicrobial compound can properly delay the growth of spoilage microorganisms and prolong the shelf life of meat products.
    Keywords: Lemon, Peppermint, Rainbow Trout, Essential Oil