فهرست مطالب

  • Volume:3 Issue: 1, 2014
  • تاریخ انتشار: 1393/05/12
  • تعداد عناوین: 8
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  • Mohsen Mirzaee, Shahin Najar, Peerayeh, Mehrdad Behmanesh, Mahdi Forouzandeh Moghadam, Abdol, Majid Ghasemian Page 1
    Background
    In fact the biofilms are composed of bacterial cells living in multicellular structures such as tissues and organs embedded within a self-produced matrix of extracellular polymeric substance (EPS). Ability to attach and biofilm formation are the most important virulence factors Staphylococcus aureus isolates. The aims of this study were to detect intracellular adhesion (ica) locus and its relation to the biofilm formation phenotype in clinical isolates of S. aureus isolated from blood cultures.
    Methods
    A total of 31 clinical S. aureus isolates were collected from Loghman Hospital of Tehran, Iran. In vitro biofilm formation ability was determined by microliter tissue culture plates. All clinical isolates were examined for determination the ica locus by using PCR method.
    Results
    Twelve (38.7%) of the isolates were strong biofilm producers. The results showed that 18(80.6%) of the isolates carried icaD gene, whereas the prevalence of icaA, icaB and icaC were 51.6%, 45.1% and 77.4% respectively.
    Conclusions
    S. aureus clinical isolates have different ability to form biofilm. This may be caused by the differences in the expression of biofilm related genes, genetic make-up and physiological conditions
  • Amin Talebi Bezmin Abadi, Tarang Taghvaei, Ashraf Mohabbati Mobarez Page 8
    Background
    Helicobacter pylori is a major human gastric for various gastro duodenal diseases. A number of putative virulence factors such as dupA, homB, tnpA have been described. To date, none were found to be significantly associated with specific H. pylorirelated diseases (e.g. gastric cancer and duodenal ulcer).
    Methods
    the primary aim of this study was to test the H. pylori hrgA genotype isolated from 253 Iranian symptomatic patients to investigate possible association with clinical outcomes. The positive culture results were confirmed by glmM (genetic control for H. pylori) PCR assay.
    Results
    The results showed hrgAgene was detected in 44/253 strains (17.3%). Prevalence of the hrgA gene was relatively high in strains isolated from duodenal ulcer patients (P 0.0063; Odd ratio: 3.54; CI 95%: 1.42-8.77).
    Conclusions
    In contrast our findings showed that the prevalence of hrgA in our control group (gastritis patients) was 22.7% (P>0.05). Conclusively, hrgA gene is a good candidate as a discriminatory biomarker for patients with duodenal ulcer
  • Arezou Taherpour, Ali Hashemi, Fatemeh Fallah, Soroor Erfani Manesh, Elahe Taki Page 17
    Background
    The aim of this study was to determine the antibacterial activity of Zataria multiflora Boiss (Avishan-e Shirazi) and Carum copticum (Zenian) extracts on Vibrio choleraee American Type Culture Collection (ATCC14035) and V. choleraee Persian Type Culture Collection (PTCC1611) strains.
    Methods
    Antimicrobial effects of the extracts were assayed by disc diffusion and broth microdilution methods.
    Results
    Using susceptibility tests, it was shown that Carum copticum methanolic extract had the highest antibacterial effect on V. choleraee standard strains at 6.25 mg/ml concentration.
    Conclusions
    Other evaluations considering herbal extracts as an antibacterial agent as well as in vivo examination of these extracts is needed to provide a natural, cost effective and strong alternative for traditionally less effective antibiotics normally used.
  • Mohammad Dadook, Sedigheh Mehrabian, Saeed Irian Page 22
    Background
    Due to the importance of the metal zinc as an essential biological element with known toxic properties, and considering the widespread secondary infections caused by Pseudomonas aeruginosa strains with resistance to antibiotics and disinfectants, the present study aimed at exploring the antimicrobial properties of the metal zinc in both clinical and environmental multiple drug resistant (MDR) strains of P. aeruginosa. MDR in P. aeruginosa is defined as the resistance to several antibiotics.
    Methods
    Bacterial strains were cultured in cetrimide agar medium at 37 ℃ for 48 h. Strains were identified both morphologically and biochemically. MIC values of the metal zinc were reported using the broth microdilution method.
    Results
    A total of 84 strains were isolated and identified. MIC values for sensitive and MDR strains were reported at 20 and 130 ppm, respectively.
    Conclusions
    It was concluded that the metal zinc at concentrations greater than 130 ppm will have an antimicrobial effect on all sensitive and MDR strains of S. aeruginosa.
  • Nastaran Agha Moghaddam, Seyed Mohammad Mahdi Hosseini, Moghaddam, Malihe Talebi, Mohammad Reza Pourshafie Page 28
    Background
    The objectives of this study were to assess the antibiotic resistance and clonality of the bacteria isolated from patients with long- (LTC) and short-terms catheterizations (STC).
    Methods
    A total of 31 clinical Staphylococcus aureus isolates were collected from Loghman Hospital of Tehran, Iran. In vitro biofilm formation ability was determined by microliter tissue culture plates. All clinical isolates were examined for determination the ica locus by using PCR method.
    Results
    Ninety seven (62%) of the samples were bacterial positive. Positive samples were significantly higher in LTC (95%) than STC (61%) patients. Escherichia coli were the predominant microorganism (32%) followed by Klebsiella pneumoniae (15%), Pseudomonas aeroginosa (11%), Enterococcus faecalis (9.2%). From the total isolates, 42% were resistant to 5 or more antibiotics. Furthermore, high prevalence of resistance amongst all isolates to ciprofloxacin (49%) was observed.
    Conclusions
    Diverse bacterial clones were observed for LTC and STC patients. Overall, the results suggested that catheterization could be a major source for growth and dissemination of highly resistant and diverse bacterial species in the hospitals.
  • Zohreh Rasooli, Parviz Owlia, Shakiba Darvish Alipour Astaneh Page 36
    Background
    Bacterial infections in burn and wound patients are common and difficult tocontrol. The aim of the current study was to evaluate the ability of full length OprF to elicit the production of protective IgG in mice burn wound sepsis model against P. aeruginosa infection.
    Methods
    OprF protein was expressed and purified by Ni-NTA. The purified protein as used to immunize BALB/c mice. The antibody raised against OprF was confirmed by ELISA and evaluated by immunoblot analysis. After burn and bacterial challenge, mortality rate was monitored in the control and immunized mice groups. Bacterial quantity in skin, blood, spleen and liver was evaluated to study spread or inhibition of the infection.
    Results
    Immunization of mice with OprF brought about a significant rise in anti-OprF sera titer. Protection was imparted in the immunized group resulting in 100% survival against 1000 fold LD50 challenge with P. aeruginosa. The antiserum against OprF was able to significantly inhibit the systemic spread of P. aeruginosa infection from the infection site to internal organs.
    Conclusions
    The results suggest that anti-P. aeruginosa OprF antibodies elicited in burn wound sepsis model by active immunization are protective against infection with P. aeruginosa, and provide a rational for further development of the vaccine for prevention against P. aeruginosa infection in burn patients.
  • Masood Reza Movahede Danesh, Kiarash Ghazvini, Ali Akbar Heydari Page 45
    Background
    Multi drug-resistant Mycobacterium tuberculosis (MDR-TB) is an infection with a causative bacillus which is resistant to at least two drugs, isoniazid and rifampin. The purpose of this study is to evaluate the prevalence of TB resistance to first-line drugs of newly diagnosed active pulmonary tuberculosis.
    Methods
    This cross-sectional study was performed on77 patients with newly diagnosed active pulmonary tuberculosis (according to national protocols of TB). Sputum samples were cultured and antibiogram for isoniazid, rifampin, pyrazinamide, ethambutol, and Streptomycin were performed on the positive cultures.
    Results
    From 77 patients with TB, 48 cases were positive sputum culture. Antibiogram was done by proportional standard method and all samples were found to be fully sensitive to all first-line TB drugs.
    Conclusions
    According to the results of this study, the primary resistance was low tothe first-line drugs for pulmonary tuberculosis of the samples collected from Khorasan, an east province of Iran. The data showed that in all patients with active pulmonary tuberculosis who were diagnosed with Ziehl–Neelsen stain of sputum, the use of the first-line drugs for tuberculosis treatment is necessary and could be sufficient.
  • Abazar Pournajaf, Abdollah Ardebili, Ezzat Allah Ghaemi, Sajad Omidi, Katayoun Borhani, Mahmoud Khodabandeh, Masoumeh Davarpanah Page 52
    Background
    Infections resulted from multi-resistant Staphylococcus aureus are increasing worldwide. In the present study, a Multiplex -PCR assay for the detection of antibiotic resistance genes among S. aureus clinical isolates and for the concomitant identification of these isolates was described.
    Methods
    A total of 127 S. aureus isolates were collected from clinical specimens at three teaching hospitals in Tehran, Iran. Screening for methicillin and mupirocin resistance in staphylococcal isolates was performed by disk diffusion method, according to Clinical and Laboratory Standards Institute (CLSI) guidelines. The presence of femB, mecA, and iles-2 genes was investigated by multiplex-PCR.
    Results
    The 62.2% and 7.8% of Staphylococcus isolates were positive for mecA and ileS 2 genes, respectively. The femB fragment was amplified in all S. aureus strains tested. There is a 100% concordance between susceptibility and PCR results for isolates which harbored ileS-2. However, 55.1% of staphylococci were found as MRSA in the phenotypic assay.
    Conclusions
    The PCR assay described in this study was able detect three genes for identification of S. aureus and its methicillin and mupirocin resistant genotypes concomitantly in a single reaction. Hence, this method can be used on regular basis as a valuable diagnostic and surveillance tool in clinical laboratories.