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Showing 3 results for Gram-Negative Bacteria
Assessment of nanopolyamidoamine-G7 dendrimer antibacterial effect in aqueous solution
Mitra Gholami , Shahram Nazari , Mahdi Farzadkia , Gharib Majidi , Soudabeh Alizadeh Matboo ,
Volume 74, Issue 3 (6-2016)
Abstract

Background: Poly(amidoamine) (PAMAM) dendrimer derivatives have been investigated for their biological applications, especially for delivery of drugs, including antimicrobial drugs to eukaryotic cells, but their effects on bacterial cells are largely unexplored. Nanotechnology and its application is one of the rapidly developing sciences. As demand of fresh drinking water is increasing, nanotechnology can contribute noticeable development and improvement to water treatment process. This study was aimed to examine synthesis and the antibacterial effect of Nanopolyamidoamine-G7 (NPAMAM-G7) dendrimer on Escherichia Coli (E. Coli), Klebsiella Oxytoca (K. Oxytoca), Pseudomonas Aeruginosa (P. Aeruginosa), Proteus Mirabilis (P. Mirabilis) and Staphylococcus Aureus (S. Aureus) from aqueous solution.
Methods: In this experimental study that has been conducted in August to December 2015 in the laboratory of microbiology of Iran University of Medical Sciences, initially dilution of 103 CFU/ml were prepared from each strain of bacteria. Then different concentrations of dendrimer (0.025, 0.25, 2.5 and 25 µg/ml) in the laboratory temperature (23-25 °C) was added to water. In order to determine the efficiency of dendrimers in removal of bacteria, samples were taken at different times (0, 10, 20, 30, 40, 50 and 60 min) and were cultured on nutrient agar medium. Samples were incubated for 24 hours at 37 °C and then number of colonies were counted.
Results: Antibacterial properties of dendrimers in aqueous solution by increasing the dendrimer concentration and contact time is directly related. At a concentration of 25 μg/ml at 60 minutes all bacteria except S. Aureus, and at 30 minutes, E. Coli and K. Oxytoca bacteria for 100% excluded. The concentration of 2.5 μg/ml at 60 minutes of bacteria, E. Coli, K. Oxytoca and P. Mirabilis are 100% excluded. All concentrations of dendrimers at different times were reduced bacteria in the PAMAM- G7 dendrimer effect on gram-negative bacteria, gram-positive bacteria was better.
Conclusion: The NPAMAM-G7 dendrimer with end amine groups exhibited a positive impact on the removal of standard strains, gram-positive and gram-negative bacteria. Therefore, it is possible to use these nanodendrimers as antibacterial in the future.


Evaluation antimicrobial activity of biogenic zinc oxide nanoparticles on two standard gram positive and gram negative strains
Mohammadreza Aflatoonian , Mehrdad Khatami , Iraj Sharifi , Shahram Pourseyedi , Mansour Khatami , Hajar Yaghobi , Mahin Naderifar ,
Volume 75, Issue 8 (11-2017)
Abstract
Background: Nanoparticles are particles that have at least one dimension between 1 and 100 nanometers. Nanoparticles are a new generation of antimicrobial agents. Nanoparticles with antimicrobial activity, especially as a new class of biomedical materials for use in increasing the level of public health in daily life have emerged.  Zinc oxide nanoparticles have attracted a great attention due to the variety of their applications in medical science. The aim of this study was to evaluate and compare the antimicrobial activity of zinc oxide nanoparticles synthesized by green method.
Methods: This experimental study was done in 2017, from March to September in the Bam Research Center of University of Medical Sciences Kerman, Iran. Green synthesis of zinc oxide nanoparticles was investigated using cumin seeds. The physicochemical characteristics of synthesized nanoparticles were studied by UV-visible ultraviolet spectrometer (Analytik Jena AG, Germany), X-ray diffraction and transmission electron microscope (TEM) (Carl Zeiss, Germany). Broth microdilution method was used to investigate the antimicrobial activity of zinc oxide nanoparticles. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of these nanoparticles were determined for Pseudomonas aerogenes and Enterococcus faecalis strains.
Results: The UV-visible ultraviolet spectroscopy showed an absorption peak in the range of 370 nm. Transmission electron microscopy shows the synthesis of zinc oxide nanoparticles, mostly spherical, with a size less than 50 nm. Minimum inhibitory concentration of zinc oxide nanoparticles against P. aerogenes and E. faecalis strains was determined at 6.25 and 12.5 μg/ml, respectively. Both bacteria were sensitive to zinc oxide nanoparticles. This sensitivity was higher for gram-negative bacteria.
Conclusion: Zinc oxide nanoparticles were produced using Iranian natural resources and our results showed significant antibacterial activity. Nanotechnology creates materials with novel properties every day, and creates new hope for improving environmental pollution. These nanoparticles can be used as a new generation of antimicrobial agents in various medical disciplines. For example, toothpaste containing zinc nanoparticles can be produced and prescribed for patients with immune deficiency to prevent the growth of microbial pathogens in the mouth and its transmission to the patient's body.
 

Short-term prognosis of definitive neonatal infection
Hassan Boskabadi, Maryam Zakerihamidi,
Volume 80, Issue 8 (11-2022)
Abstract
Background: Neonatal sepsis is a severe systemic bacterial infection that affects on premature neonates prognosis. Therefore, the aim of this study was to evaluate the short-term prognosis of neonate's infection.
Methods: The present study is a cross-sectional study that was performed on 729 neonates suspected of infection, in neonatal ward in Ghaem Hospital of Mashhad since May 2015 to May 2022 by available sampling. The data collection tool was a researcher-made checklist containing neonatal characteristics (gestational age, birth weight, first and fifth minute Apgar score, and neonatal status at discharge) and laboratory information (White Blood Cell, Platelet (PLT), C-reactive Protein, Blood culture, Cerebrospinal fluid culture). Infants with congenital infection, congenital anomaly and positive blood cultures without clinical and laboratory symptoms were excluded from the study. Neonatal prognosis was compared in terms of death or discharge among neonates with and without definitive infection. First, we described the results using statistical tables and graphs, and then, data were analyzed by Kolmogorov-Smirnov, T test and SPSS software, version 26 (IBM SPSS, Armonk, NY, USA). P<0.05 considered as significant.
Results: According to the results of this study, low birth weight and lower gestational age and lower Apgar score increase the risk of neonatal death. About one-fifth of infants died of definitive infection. The cases of death due to infection in the group of deceased infants were about 4 times higher than in the group of discharged infants. About one third of the babies with sepsis and half of the babies with meningitis died. Forty-four percent of infants with early sepsis and 40% of infants with late sepsis died. In cases of neonatal death due to sepsis, the most common gram-negative infectious agent was Acinetobacter and the most common gram-positive infectious agent was Enterococcus.
Conclusion: Neonatal definitive infection worsens their prognosis. So, the risk of neonatal death increases by 5 times. The probability of death in meningitis is more than sepsis and in early sepsis is more than late sepsis and in sepsis due to gram-negative is more than gram-positive.

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