Dr. Mohammad Reza Pourshafie
Vol 7 No 3-4 (2018)
Background: We describe here two rare case of Ralstonia pickettii infection associated with tonsillitis and wound infection. Ralstonia pickettii is a gram negative bacteria, usually isolated from the soil and water. Infection-associated Ralstonia species though rare, has become an emerging nosocomial pathogen due to its capability to survive in harsh conditions like antiseptic solutions. Both of our reported cases presented to the outdoor patient unit and thus possibility of community acquired Ralstonia picketti infection cannot be ruled out. Methods: Isolates were subjected to Siemens MicroScan WalkAway 96 Plus (Beckman Caulter Diagnostics, USA) for identification and antimicrobial susceptibility testing. Results: Ralstonia pickettii was identified as a rarely detected pathogen. Conclusion: Ralstonia pickettii though rarely associated with wound infections and tonsillitis, could be a potential hospital acquired pathogen.
Antimicrobial Activities of some Plant Extracts against Phytopathogenic Fungi and Clinical Isolates in IranBackground: Natural products from plants as environmentally safe options have received attention for controlling various phytopathogenic diseases. In this study, the antimicrobial activities of three plant aqueous and alcoholic extracts (Salvia officinalis, Peganum harmala and Oxalis corniculata) against phytopathogenic fungi (10 fungal isolates associated with diseased tomato fruits) and clinical isolates (10 bacterial isolates) and Candida albicans, as a pathogenic yeast model, were investigated in the Gilan province of northern Iran. Methods: After phytochemical screening of plant extracts, antimicrobial activity of the extracts evaluated by standard methods for determination of MIC and MBC. Results of the phytochemical screening of aqueous and alcoholic leaf extracts of the selected three plants revealed the presence of saponins, steroids, tannins, glycosides, alkaloids and flavonoids. Results: All three extracts of the plants tested showed varying degrees of antimicrobial activities against both phytopathogenic fungi and bacteria. Generally, the methanol extracts were more active than other extracts for S. officinalis and P. harmala, whereas for O. corniculata water extract showed more antimicrobial activity. Conclusion: The study has been able to establish and document the important medicinal plants which can be used in the management of phytopathogens and infectious diseases in Iran.
Nanoparticles Impact the Expression of the Genes Involved in Biofilm Formation in S. aureus, a Model Antimicrobial-Resistant SpeciesBackground: Infection with resistant bacteria are still reported in hospitals despite the routine cleaning of hospital surfaces. Presence of drug-resistant microbes in the on environment of hospitals and on medical equipment is indicative of the need for control measures which could impact the emergence of such microbes. In addition, biofilms are increasingly associated with human infections and it necessitates careful considerations on usage of a diverse range of medical devices, such as catheters, implants and pacemakers in hospitals. Methods: This study was designed to compare the effect of silver, ZnO nanoparticles and curcumin on drug-resistant Gram-positive and Gram-negative bacteria which were already isolated from different wards of the hospital. The MIC value were determined for silver, curcumin and ZnO nanoparticles. As the second step, the expression level of the genes involved in biofilm formation in S. aureus, including icaA, icaD, fnbA and fnbB, was studied to analyze the physiological reaction to controlled concentrations of such nanoparticles using RT-qPCR assessments. Results: In this study, a total of 172 bacterial isolates were recovered from clinical and environmental samples (96 and 76 isolates, respectively). API-20 test revealed that these isolates belonged to 8 species. All antimicrobial resistant isolates were susceptible to the metal oxide nanoparticles. The results of q-PCR in this study showed that the expression of icaA and icaD genes in the presence of silver, curcumin and zinc nanoparticles were not significantly reduced compared to the control samples. But, exposure to nanoparticles reduced the expression of fnbA and fnbB genes from 0.46 to 0.06. Conclusion: The results of our study showed that nanoparticles are highly effective on antibiotics- resistant isolates and these compounds can be used in the treatment of resistant bacteria. In addition, this study also demonstrates the promising potential of using nanoparticles as anti-biofilm formation agents.
Methicillin-Resistant Staphylococcus aureus Using Broth Micro Dilution Method in Iran: A Meta-Analysis (2007-2016)Background: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most signifuicant pathogens in Iran; it is one of the WHO-declared microbial resistance emergencies; and also one of the most important challenges facing the prevalence of resistance. The aim of this study was to detect MRSA using Broth Micro Dilution method and meta-analysis in Iran from 2007 to 2016. Methods: Persian databases (including Magiran, Irandoc, and SID) and International databases (including pubmed, science direct, and scopus) were searched during this period (2007-2016), such that the high heterogeneity (50% < I2) in this study was analyzed using the DerSimonian Laird method. Data were categorized into subgroups based on year of study and province. Due to the high validity of the diagnosis of organisms and quantitative results, antimicrobial susceptibility test (AST) was used to detect MRSA. Data analysis was performed using statsdirect software. Results: Based on the available data in medical databases, 678 articles were selected. In total, 29 remaining studies entered the meta-analysis phase. In this study, the overall prevalence of MRSA using MIC is 53% (95% CI: 0.42.31, 63.90); in 2016 it was 77.56% (95% CI: 76.07, 78.99) and in 2007 was 57.49% (95% CI: 53.17, 61.72). The heterogeneity was estimated to be 98.5% (95% CI: 98.4, 98.6). Conclusion: Based on the results, there is an increasing prevalence of MRSA in Iran. These may be due to the failure or lack of infection control activities and antimicrobial selection pressure.
Background: Probiotics mainly belong to Lactobacillus spp. and they are useful for humans in appropriate amounts. The present study aimed to determine antibiotic resistance patterns of such bacteria isolated from probiotic yogurts of Iran. Methods: Probiotic bacteria were isolated from 7 yogurt samples and the isolates were identified by conventional methods and then confirmed using polymerase chain reaction (PCR) technique. Antibiotic susceptibility test was performed by disc diffusion test in order to determine isolates antibiotic resistance patterns. Results: From 7 yogurt samples, 8 isolates were recovered and PCR assay also showed that the isolates belong to Lactobacillus delbrueckii subsp. bulgaricus. Antibiotic susceptibility testing showed that three isolates from three brands were resistant to vancomycin and gentamicin. Other strains were susceptible to all tested antibiotics. Conclusion: Low resistance rate to antibiotics among Iranian probiotic bacteria indicate that the consumption of their products is safe but their clearance following antibiotic therapy can be unfavorable. Hence, applying probiotic strains with non-transferrable resistance elements in probiotic yogurts can be a useful strategy to make stable probiotic products.
Background: Meningococcal disease as a worldwide health problem causes approximately 1.2 million cases of bacterial meningitis, annually. Neisseria meningitidis a major cause of bacterial meningitis and serious diseases such as sepsis and bacteremia is fatal, and despite antibiotic treatments, the mortality rate of about 135 thousand cases has been reported. Meningococcal pathogen has been detected in nasopharynx of about 10-40% of the healthy people. There are several vaccines against six major groups of bacteria A, B, C, W135, X and Y. Although the bivalent (C-B), trivalent (A-C-Y) and quadrivalent (A-C-Y-W135) vaccines are used these days, there are yet significant rates of the disease in different geographical areas. Conclusion: Although the polysaccharide capsule conjugate vaccine that have been developed against meningococcal serogroups A-C-Y and W135 are successful, but serogroup B because of the similarity with human polysialic glycoproteins is poorly immunogenic and to be cross-reactions. Thus, vaccines based on outer membrane vesicles have been designed for them