فهرست مطالب

  • Volume:1 Issue: 3, 2012
  • تاریخ انتشار: 1391/09/25
  • تعداد عناوین: 8
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  • Hajar Mohammadi, Barzelighi, Mahshid Talebi, Taher, Maryam Adabi, Seied Ali Javad, Moosavai, Mosadegh Jabbari, Abdolaziz Rastegar Lari Page 1
    Background
    Multi-drug resistant strains of Acinetobacter spp. have created therapeutic problems worldwide. The objective of this study was to detect integrons in Acinetobacter spp. isolates from Ventilator-Asso­ciated Pneu­monia patients using PCR method.
    Methods
    A total 51 Bronchoalveolar lavage samples were obtained from pa­tients in ICU and examined for Acinetobacter spp. infection by bio­chemi­cal and PCR methods using blaOXA51-like primers. An­timi­crobial suscep­tibility testing was performed using disk diffusion and MIC me­thods.
    Results
    Among 51 patients with VAP (62.7% males, 35.2% females, mean age 53 year), 50 (98%) were positive, with a high prevalence of gram-nega­tive bacteria, mainly Acinetobacter spp. (70%), from which A. baumani was detected in 34 (68%) and A. lwoffii in 1 (2%) of iso­lates. More than 90% of isolates were resistant to imipenem, pipera­cil­lin+tazobactam, third genera­tion cephalosporins and gentamicin, while the most effective antibiotic was colistin (100%). The correla­tion coeffi­cient between disk diffusion and MIC was 0.808 (p = 0.001). Three Aci­netobacter isolates (8%) harbored integrase I gene but none of isolates contained Class II or III integrons.
    Conclusion
    The results showed that colistin was an effective antibi­otic and can be used for treatment of patients in ICU. Due to the high number of MDR isolates lacking Integrons it can be concluded that although class I in­tegrons are important among clinical isolates of A. baumannii, they have no significant role in dissemination of antibiotic resistance genes in Rasoul Akram Hospital in Tehran, Iran. The pres­ence of IntI in A. lwoffii may be related to transfer of integron to A. baumannii which can be con­sidered as an important threat for hospi­talized patients.
  • Jalil Fallah Mehrabadi, Gholamreza Goudarzi, Fatemeh Farahani Hatamabadi, Hedroosha Molla Agha Mirzaei, Sarah Najafi Page 10
    Background
    The prevalence of Urinary Tract Infection (UTI) is really high in the world. Escherichia coli is a major agent of UTI. One of the strategies for decreasing UTI infections is vaccine development. As the attachment is a really important stage in colonization and infection, at­tachment inhibition has an applied strategy. FimH protein is a major factor during bacterial colonization in urinary tract and could be used as a vaccine. Thus, it was considered in this research as a candidate antigen.
    Methods
    The sequences of fimH and acmA genes were used for designing a synthetic gene. It was cloned to pET23a expression vector and transformed to E. coli (DE3) Origami. To confirm the expression of recombinant protein, SDS-PAGE and western blotting methods were used. Subsequently, recombinant protein was purified. On the other hand, Lactobacillus reuteri was cultured and mixed with FimH / AcmA recombinant protein. The rate of protein localization on lactobacillus surface was assessed using ELISA method.
    Results
    It was showed that the recombinant protein was expressed in E. coli (DE3) Origami and purified by affinity chromatography. Moreover, this protein could be localized on lactobacillus surface by 5 days.
    Conclusion
    In current study, a fusion recombinant protein was pre­pared and displayed on L. reuteri surface. This strain could be used for animal experiment as a competitor against Uropathogenic E. coli (UPEC). Using manipulated probiotics strains instead of antibiotic ther­apy could decrease the antibiotic consumption and reduce multi-drug resistant strains.
  • Anand Kalaskar, Kandi Venkataramana Page 17
    Background
    The prevalence of antibiotic resistance among extended-spectrum β-lactamase (ESBL) producing Escherichia coli and Kleb­siella pneumoniae has been increased markedly in recent years. The present study was done to know the prevalence of ESBL production among isolates of E. coli and K. pneumoniae and to study the susceptibility pattern of isolates against different antibiotics.
    Methods
    Extended-spectrum β-lactamase producing E. coli and K. pneumoniae were isolated from various samples ob­tained from outdoor and indoor patients of the Prathima Institute of medical sciences, Andhra Pradesh, India. They were tested for ESBL production by double disc synergy test and resistance to various anti­biotics like fluoroquinolones, cephalosporins, aminoglycosides and ß-lactamase inhibitor combinations and susceptibility to carbapenems were determined by Kirby-Bauer disc diffusion method.
    Results
    A total of 94 ESBL producing isolates were obtained. Of them 60 were E. coli and 34 K. pneumoniae. They were obtained from urine, sputum, pus, wound swabs blood & tracheal aspirates. Urine (38.29%) was the main source of ESBL-producing isolates from all patients, fol­lowed by sputum (34.04%). About 37.23% of these isolates were col­lected from medical wards and 27.65% were collected from outdoor. All isolates were susceptible to imipenem. The resistance to cephalos­porins (1-4 generations) was almost 100%. Resistance to Aztreonam, Ampicillin and Co-amoxyclav was also 100%. A high degree of resis­tance was observed to other antibiotics.
    Conclusion
    The highest prevalence of resistance to ESBL in E. coli and K. pneumonia is associated with a multitude of infections in hospita­lized patients with a significant longer duration of hospital stay, in­creased morbidity and greater hospital charges. Advanced drug resis­tance surveillance and molecular characteristics of ESBL isolates is ne­cessary to guide the proper and judicious antibiotic use.
  • Hossein Fazeli, Hooman Sadighian, Bahram Nasr Esfahani, Mohammad Reza Pourmand Page 25
    Background
    Pseudomonas aeruginosa is one of the most important oppor­tunistic pathogens responsible for various types of infections. Children suffer significant morbidity and mortality due to nosocomial infections. The aim of this study was to investigate the presence of Class-1 integron, blaBEL, blaPER, blaKPC, blaVIM, blaIMP and blaOXA-group-1 genes among P. aerugi­nosa isolates at Children''s Medical Center Hospital in Iran and to determine phenotypic evidence of ESBL and MBL production.
    Methods
    Antibiotic susceptibility tests were analyzed for 72 P. aeruginosa clinical isolates. Isolates were identified by using biochemical tests and con­firmed by PCR assay for oprL gene. ESBL and MBL producer isolates were identified by phenotypic tests (double disc synergy tests). Detection of β-lactamase genes and class-1 integron were performed by PCR method.
    Results
    All of the isolates were susceptible to ceftazidime / clavulanate, me­ropenem, imipenem and ciprofloxacin. About 83.3% and 16.7% of isolates were resistant to ceftazidime and amikacin respectively. Approximately, 83.3% of isolates were considered as potential ESBL producers. None of the clinical isolates showed above β-lactamase genes. It seems that, the reason is the absence of class-1 integron in all of isolates. About 16.7% of strains were identified as multidrug resistant. Fortunately, all of the isolates were sus­ceptible to meropenem and imipenem which are effective against ESBL pro­ducing strains.
    Conclusion
    The absences of class-1 integron decreases the probability of acquired β-lactamase especially MBL. Thus, absolute susceptibility to carba­penems and ciprofloxacin among P. aeruginosa isolates in pediatric hospital has important implications for empirical antimicrobial therapy. It seems that these properties help to decrease mortality of nosocomial infections within children.
  • Mohammad M. Farajollahi, Sepideh Hamzehlou Page 37
    Background
    Tuberculosis is a crucial health problem. Establishing a rapid, reliable and still inexpensive diagnostic method for tuberculosis seems to be substantial in developing countries where TB has very high incidence rate.
    Methods
    An Indirect Enzyme-linked immunosorbent Assay (ELISA) was established to detect serum antibodies against Mycobacterium tuberculosis. Three kinds of antigens were used to prepare the solid phase for antibody as­say including: purified protein derivative (PPD), M. tuberculosis Bacilli, and Mycobacterium bovis Bacillus Calmette Guerin (BCG). Sera of two main following groups were investigated in this study: sera samples from smear-positive, culture-positive and Tuberculin Skin Test-positive TB pa­tients and sera samples from smear-negative, culture negative and TST-nega­tive healthy individuals.
    Results
    Among the antigens used, BCG produced higher sensitivity and spe­cificity in the assay. With PPD as the solid phase, higher sensitivity, but lower specificity was observed in comparison with BCG. Both, low response and noise (non-specific binding) were observed with TB bacilli as the solid phase in the assay.
    Conclusion
    Using BCG solid phase system in this method resulted in higher sensitivity in comparison to single antigen solid phase systems. In addition, we were able to circumvent the problem of non-specific bindings in more popular multi-antigenic solid systems such as PPD. By using this new indi­rect ELISA, a rapid, reliable and still inexpensive diagnosis of tuberculosis might be possible. Although, further investigations are required to confirm our result.
  • Rokhsareh Sadeghi, Parviz Owlia, Roya Yaraee, Fatemeh Sharif, Ferial Taleghani Page 44
    Background
    The antimicrobial activity of silver nanoparticles has been investigated in medical fields in recent years, but there are few studies regarding its effect on oral microorganisms. The aim of the present study was to evaluate the in vitro antimicrobial and toxicity properties of nanosilver against two dental plaque microorganisms and Human Gin­gival Fibroblast (HGF) cell line.
    Methods
    Antibacterial effects of nanosilver colloidal solution were determined by minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) using microdilution method. Standard strains of Streptococcus sanguis and Actinomyces viscosus were used. For toxicity assessment, MTT and LDH tests were performed under controlled conditions. Different concentrations of nanosilver were pre­pared and their toxic effects on HGF were determined after 24, 48 and 72 hours.
    Results
    The MIC of nanosilver solution for S. sanguis and A. viscosus were 16 and 4 µg/ml, respectively. The MBC of nanosilver was 64 µg/ml for S. sanguis and 16 µg/ml for A. viscosus. MTT results showed that after 24 hours the concentrations of ≥ 0.5 µg/ml of nano­silver solution affected cell viability when compared with control group. After 48 and 72 hours only the concentration of ≥ 5 µg/ml showed significant effect on cultured cell viability. LDH release test demonstrated toxic effect only after 48, 72 hours by 20 and 50 µg/ml of nanosilver.
    Conclusion
    The results demonstrated that beside its antibacterial activ­ity against S. sanguis and A. viscosus, nanosilver mediated a concentra­tion and time dependent cytotoxicity on HGF.
  • Ahmad Reza Zarifian, Emran Askari, Mohammad Reza Pourmand, Mahoboobeh Naderi, Nasab Page 53
    Background
    Staphylococcus aureus is a major human pathogen worldwide. Vancomycin has been used for decades to treat multidrug resistant S. aureus. Ten years has passed since the first report of van­comycin resistant S. aureus (VRSA). The objective of this systematic review was to determine the total number of VRSA isolates that have been reported from Iran.
    Methods
    Search terms reflected “Iran”, “vancomycin” and “S. aureus” were searched in the ISI web of knowledge, PubMed, SciVerse, and Google scholar. Also two Persian scientific databases and 13 recent national congresses were investigated. Articles / abstracts working on S. aureus in Iran, evaluating vancomycin MIC and/or PCR of vanA/B were included in this systematic review.
    Results
    Out of the 3484 records found in mentioned resources, 13 re­lated studies were included in the final analysis. The result showed that at least 24 VRSA isolates which have been reported from Iran up to September 2012.
    Conclusion
    It seems that many Iranian researchers did not follow a specific guideline for reporting and confirming VRSA. Establishing an Iranian reference center where studies on VRSA can be registered, evaluated and confirmed is strongly recommended.
  • Mohammad Reza Pourmand, Sanaz Dehghani, Marziyeh Hadjati, Farid Kosari, Gholamreza Pourmand Page 62
    A 56 years old man was referred to our center for renal transplantation. He had been diagnosed with renal failure three months before admission and was on regular hemodialysis from then on. The urinalysis showed pyuria and hematuria and moderate bacteriuria. The urine culture was negative. Ultrasonography showed multiple stones in both kidneys. Right nephroctomy was conducted to remove infection. After the first nephrectomy, the pathologic study of the removed kidney showed renal actinomycosis. Renal actinomycosis should be considered as a possible cause of infection in patients with end-stage renal disease.