Vol 3 No 1-2 (2014)

Original Articles

  • XML | PDF | downloads: 667 | views: 4151 | pages: 1-7
    Background: In fact the biofilms are composed of bacterial cells living inmulticellular 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 bloodcultures.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.
  • XML | PDF | downloads: 251 | views: 364 | pages: 8-16
    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. pylori-related 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 hrgA gene 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
  • XML | PDF | downloads: 331 | views: 355 | pages: 17-21
    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 cholerae American Type Culture Collection (ATCC14035)and V. cholerae 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. cholerae 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.
  • XML | PDF | downloads: 591 | views: 586 | pages: 22-27
    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 bothclinical 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 °C 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 ppmwill have an antimicrobial effect on all sensitive and MDR strains of P. aeruginosa.
  • XML | PDF | downloads: 211 | views: 290 | pages: 28-35
    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 ofresistance 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.
  • XML | PDF | downloads: 409 | views: 561 | pages: 36-44
    Background: Bacterial infections in burn and wound patients are common and difficult to control. 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.
  • XML | PDF | downloads: 320 | views: 358 | pages: 45-51
    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 on 77 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 tuberculosis, 48 cases have 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 to the 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.
  • XML | PDF | downloads: 403 | views: 531 | pages: 52-59
    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 isolateswas 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 andLaboratory 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.