• Frequency of bacteria isolated from blood cultures and compare antibiotic-probiotic resistance with silver nanoparticles
  • Zahra Hojjati Bonab,1,* somayyeh Taghizadeh,2 Mitra Behjati,3
    1. Assistant Professor of Microbiology, Faculty of Basic Sciences, Islamic Azad University Bonab Branch, Bonab, Iran
    2. PhD of microbiology
    3. M.Sc. of Microbiology, Faculty of Basic Sciences, Islamic Azad University Bonab Branch, Bonab, Iran


  • Introduction: Blood infections are very dangerous ones, especially if it is not treated properly, it can lead to high mortality. The purpose of this study is to investigate the frequency of separated bacteria from cultivated blood and to compare antibiotic-probiotic resistance pattern with silver nano-particles.
  • Methods: In this study, the bacteria in taken samples from patients are identified and The antimicrobial property of standandard Lactobacillus Acidophilus supernatant and silver nano-particles is investigated utilizing The Well Diffusion Agar method. The antibiogram test also is conducted for several antibiotics by applying the Disk Diffusion Agar method. In order to reduce the error, each test is repeated three times and diameter of non-growth zone and its antimicrobial ability is compared together.
  • Results: The results are analyzed by SPSS software, version 21 and P value <0.05 is considered meaningfully.From, the bacteria in taken samples from patients, four types of bacteria are identified; Staphylococcus aurous, Staphylococcus epidermidis, Klebsiella, Escherichia coli. Out of these bacteria, Escherichia coli get the maximum value of frequency and Staphylococcus epidermidis minimum. All of the identified bacteria have different reaction in relation to 10 types of antibiotics. Klebsiella shows the highest sensitivity toward novobiocin. The gram negative bacteria including Klebsiella and Escherichia resist to supernatant. Among the gram positive bacteria, Staphylococcus aurous shows the highest and Staphylococcus epidermidis the lowest diameter of non-growth zone to supernatant. For Staphylococcus aurous and Staphylococcus epidermidis, it shows MIC= 0.5 µl/ml , MIC=0.01 µl/ml to supernatant, respectively. Both bacteria do not have MBC. Klebsiella shows the maximum and Staphylococcus epidermidis the lowest sensitivity to silver nanoparciles. The value of MIC for Klebsiella, Escherichia coli, Staphylococcus aurous, Staphylococcus epidermidis are MIC= 0.12 µl/ml , MIC=0.6 µl/ml , MIC=0.6 µl/ml , MIC=0.12 µl/ml respectively and the amount of MBC for these bacteria are MBC= 0.25 µl/ml , MBC= 0.6 µl/ml , MBC=0.12 µl/ml , MBC=0.12 µl/ml respectively.
  • Conclusion: In this study Escherichia coli has the maximum frequency among the blood samples. This shows that these bacteria can be a common factor in blood infection. However, the most bacteria resist to antibiotics. So it needs to apply new methods to fight with infections. All gram positive bacteria in this study are sensitive to supernatant and the whole of bacteria are sensitive to silver nano-particles. These outcomes show the high anti-microbe potentiality in them.
  • Keywords: bacteremia, antibiotic resistance, probiotic, supernatant, Ag nanoparticle