فهرست مطالب

Medical Microbiology and Infectious Diseases - Volume:4 Issue: 1, 2016
  • Volume:4 Issue: 1, 2016
  • تاریخ انتشار: 1395/05/02
  • تعداد عناوین: 8
  • Alireza Milani, Marzieh Basirnejad, Sepideh Shahbazi, Azam Bolhassani Pages 1-7
    Diagnosis of infectious diseases remains an important issue in medical science. Identification of biomarkers can be used to predict early infections. Recently, heat shock proteins (HSPs) have been known as the conserved compounds expressed under stress conditions in both prokaryotic and eukaryotic systems. These proteins act as molecular chaperones. Several studies showed the increased levels of HSPs in patients suffering from infectious diseases suggesting the role of HSPs as promising biomarkers. Also, Hsps possess significant roles in antigen presentation, the maturation of dendritic cells and the activation of lymphocytes. Thus, these proteins can be utilized to develop vaccines in bacterial and viral infections. In this mini-review, we will briefly describe the important roles of HSPs in diagnosis and immunity in bacterial and viral infections.
    Keywords: Heat shock protein, Infection, Biomarker, Immunity
  • Kayhan Azadmanesh, Sana Eybpoosh Pages 8-10
    Bayesian evolutionary analysis provide a statistically sound and flexible framework for estimation of evolutionary parameters. In this method, posterior estimates of evolutionary rate (μ) are derived by combining evolutionary information in the data with researcher’s prior knowledge about the true value of μ. Nucleotide sequence samples of fast evolving pathogens that are taken at different points in time carry evolutionary information that allow for estimation of evolutionary rates and divergence dates. If the amount of genetic change in the data is proportional to the time elapsed since divergence from the common ancestor, then one can directly estimate the μ from the data. Otherwise, external sources should be used to select the μ value, and use it as a fixed prior in Bayesian evolutionary analysis. This note provides a brief overview on how to assess the adequacy of the evolutionary information in the data and provides some recommendations for obtaining proper evolutionary rate priors from external sources. The recommendations generally highlight the need for the candidate μ prior to be a good representative of the evolutionary rate in the data at hand. This will be achieved by ensuring that the samples that are the source of the candidate μ value have been under relatively similar evolutionary forces as the data at hand. As the evolutionary forces acting on a particular set of samples varies across different study settings and species type, selection of prior for μ should be founded on a thorough understanding of the species under study at biological and social levels.
    Keywords: Evolution, Evolutionary rate, Bayesian Evolutionary Analysis, Phylogeny
  • Maryam Esmaeili, Samaneh Saberi, Mehdi Alikhani, Mojgan Hatefi, Mohammad Tashakoripour, Mahmoud Eshagh Hosseini, Mohammad Ali Mohagheghi, Marjan Mohammadi Pages 11-15
    Helicobacter pylori, as an etiologic cause of peptic ulcers and gastric cancer, should be tested and treated. The true state of infection can only be detected by isolation of gastric biopsies through the invasive method of gastroscopy. However, there are several non-invasive methods for detection of infection, the most common of which is serology.
    Here we have evaluated the efficacy of two commonly used commercial IgG-based ELISA kits (Kit-1 and Kit-2) against the endoscopy (biopsy)-based methods of rapid urease test (RUT) and bacterial culture. Our study population included 754 subjects categorized as having: 1) nonulcer dyspepsia (NUD, N=485), 2) peptic ulcer disease (PUD, N=65), and 3) gastric cancer (GC, N=204).
    The rates of agreement between the results obtained by Kit-1, Kit-2 and both kits with culture/RUT were 62.4% (318 of 500, P=0.0001), 74.4% (183 of 246, P96% and >99%) were significantly reduced (Kit-1: 94.4% and 40.3%; Kit-2: 86.5% and 71%) for the Iranian population.
    Our data raises questions regarding the accuracy of commercial IgG-based ELISA kits for the detection of H. pylori infection. Therefore, caution should be practiced when such tests are used as the sole basis of medical decision making.
    Keywords: Serology, ELISA, Sensitivity, Specificity, Gold Standard
  • Ehsan Mostafavi, Fahimeh Bagheri Amiri, Sahar Khakifirouz, Saber Esmaeili, Fatemeh Kazemi-Lomedasht Pages 16-19
    Livestock is a known source of Crimean-Congo Hemorrhagic Fever (CCHF) virus infection in humans. Although CCHF is endemic in Iran, limited human cases of CCHF are reported from northwest of Iran. Considering the lack of complete and updated information on the status and distribution of CCHF infection among domestic animals in Ardabil province, this study was conducted to investigate the CCHF status among sheep in this area.
    In this study, 256 sera from sheep were collected from various geographical regions of Ardabil in 2011, and tested for specific CCHF IgG antibodies by ELISA.
    The Seroprevalence of CCHF in this area was 27.34%. The seropositivity rate of CCHF in northern regions (36.36%) was higher than in central (26.27%) and southern (20%) regions. The highest and lowest seropositivity of CCHF were seen in Parsabad (45.57%) and Khalkhal counties (17.78%), respectively.
    In this study, a relatively high seroprevalence of CCHF was seen among livestock in the province. Therefore, health care system should increase its surveillance for the detection of CCHF patients. Molecular studies to compare the virus strains circulating in this province and those in the eastern regions of the country can shed more light on the epidemiology of the disease.
    Keywords: CCHF, Seropositivity, Epidemiology, Zoonosis, Iran
  • Hamid Sharifi, Morteza Abbasi, Sana Eybpoosh, Javad Alinejad, Hesameddin Akbarein Pages 20-24
    Brucellosis is a major health problem in northeast of Iran. There is not much data on the association of nutrition and lifestyle factors with the risk of brucellosis in this area. We conducted the present study to determine the risk factors of brucellosis in Khorasan-e Razavi Province, northeastern Iran.
    we conducted a case-control study from July 2015 to March 2016 in three cities of Khorasan-e Razavi Province. Cases and controls were recruited from individuals attending primary care and were matched together based on their age (± 2 years) and gender. Clinical and epidemiological data were collected with a valid questionnaire. Conditional logistic regression was used in Stata software V13.
    We recruited 180 incident cases and 360 controls, of which 53.9% were male, and 90.0% were living in rural areas. Consumption of unpasteurized yogurt (OR): 5.4; 95% CI: 2.5-11.5), milk (OR: 6.0; 95% CI: 3.0-11.9), and cheese (OR = 3.7; 95% CI: 1.7-8.1), as well as engagement in livestock-related occupations (OR: 2.6; 95% CI: 1.2-5.2) significantly increased the adjusted risk of brucellosis. Conversely, having academic education (OR: 0.1; 95% CI: 0.01-0.5), consuming unpasteurized butter (OR: 0.4; 95% CI: 0.2-0.8), and timely animal vaccination (OR: 0.3; 95% CI: 0.1-0.5) had a protective effect on brucellosis.
    The risk factors identified in this study are lifestyle- and occupation- related modifiable factors. So, the disease incidence is expected to decrease in this region with modification of these risk factors, such as animal vaccination, personal protection at work, and public health education.
    Keywords: Brucelloses, Case Control, Risk Factors, Iran
  • Sepideh Farmand Azadeh, Najmeh Zarei, Vahid Khalaj, Mohammad Azizi Pages 25-30
    Aspergillus fumigatus is the leading cause of invasive aspergillosis in immunocompromised patients with a high rate of mortality. Despite introduction of several classes of antifungal drugs, the limitations of current therapies have prompted an intense research toward the discovery of new antifungal compounds. In a recent study, several potential drug targets were identified based on in silico comparative proteome analyses of A. fumigatus and Saccharomyces cerevisiae. A potential target, capsule polysaccharide synthase1 (CPS1) homolog gene, was identified and chosen for further study.
    The genome sequence of CPS1 homolog in A. fumigatus (AfuCPS1) was retrieved from the database and analyzed. The RT-PCR analysis was carried out to show the presence of the transcripts. A gene disruption cassette was prepared and subsequently transformed into A. fumigatus strain AF293. An AfuCPS1 disruptant strain was isolated and further analyzed.
    The AfuCPS1 gene sequence was annotated, and the signal sequence and a glycosyltransferase motif were identified. The RT-PCR analysis showed that AfuCPS1 is expressed throughout the life cycle of the fungus. The AfuCPS1 mutant showed normal colony morphology. Antifungal susceptibility assay of the mutant using different classes of known antifungal drugs confirmed a similar susceptibility pattern to the wild-type strain. However, spore germination was affected, and a delay in germination was observed.
    The findings showed that the AfuCPS1 is not essential for the normal growth of A. fumigatus. More investigation is underway to elucidate the physiological role of this gene in spore germination process.
    Keywords: Aspergillus fumigatus, Cell wall, Gene, Spores, Aspergillosis
  • Purimitla Usha Rani, Payala Vijayalakshmi Pages 31-36
    Non-fermentative Gram-negative bacilli (NFGNB) are occasionally involved in infectious diseases pathology, but have shown resistance to multiple antibiotics and the capability to gain new resistance factors in the hospital environment. The present study was aimed to investigate the antibiotic susceptibility pattern of rare NFGNB isolated from different clinical samples and the prevalence of Metallo-beta-lactamase (MBL) producing non-fermenters among the carbapenem-resistant isolates.
    A total of 250 clinical samples from the patients suffering from various infections were analyzed by using different standard microbiological techniques like microscopy, culture methods, biochemical reactions and antibiotic susceptibility using Kirby-Bauer method. MBL detection was performed by imipenem-EDTA combined disc test and imipenem-EDTA double disc synergy test (DDST).
    The non-fermenters bacteria rate isolated from different clinical samples was 4.8%. The highest rate of non-fermentative isolates was observed in patients with hospital-acquired infections (91.6%). The various species of NFGNB included Pseudomonas putida (33.3%), Pseudomonas stutzeri (25%), Burkholderia cepacia (16.6%), Achromobacter xylosoxidans (16.6%) and Ochrobactrum anthropic (8.33%). The isolates showed high resistance to carbapenems, and the incidence of MBL producing non-fermenters among the carbapenem-resistant organisms was found to be 100%.
    NFGNB are now emerging as organisms of nosocomial infections. The use of broad spectrum antibiotics should be avoided, and quick detection and efficient infection control measures are essential to prevent further spread of MBLs to other Gram-negative bacilli. Detection of MBL production and rationale antibiotic usage are the most important factors which control the gradually increasing NFGNB related infections.
    Keywords: Non-fermenting Gram-negative bacilli, Carbapenems, Metallo-beta-lactamase
  • Mehdi Fazlalipour, Vahid Baniasadi, Mohammad Hassan Pouriayevali, Tahmineh Jalali, Tahereh Mohammadi, Sanam Azad-Manjiri, Yasaman Jamshidi, Sara Azizizadeh, Motahareh Hosseini, Sahar Khakifirouz, Mostafa Salehi-Vaziri Pages 37-38
    Crimean-Congo hemorrhagic fever (CCHF) is considered as the most important arboviral infection in Iran. Early diagnosis of CCHF is essential for preventing the spread of the infection and providing appropriate treatment to patients. Given that clinical symptoms of CCHF may overlap with other common infectious disease; differential diagnosis is a matter of great importance. In this report, we describe a case of rheumatoid arthritis intoxicated with methotrexate mimicking CCHF. This observation suggests that non-infectious medical conditions such as drug toxicity should be considered as a possible differential diagnosis of CCHF.
    Keywords: Crimean-Congo Hemorrhagic Fever, Differential Diagnosis, Methotrexate