Kargar, M, Ebrahimi, E, Amini, J, Najafi, A, Kheirkhah, B,
Volume 8, Issue 4 (supplement Issue[PERSIAN] 2015)
Abstract
Abstract
Background and Objective: Listeria monocytogenes is a bacterium transferred by foods and is the agent of many sporadic and epidemic diseases in humans. This study aimed to investigate the prevalence of L. monocytogenes and to determinine their antibiotic resistance profile in red meats.
Material and Methods: this cross-sectional study was performed on 400 red meat samples obtained from industrial slaughterhouses placed in Kerman, Iran. First, the samples were enriched with Simultaneous Enrichment Broth (SEB), and then plated onto Palcam agar and Tryptic Soy Broth Yeast Extract Broth (TSAYE). After identification of the isolates based on biochemical tests and PCR, the isolates were checked for their antibiotic resistance profile using disk Diffusion
Results: of 400 samples, 12 samples (3%) were contaminated with different species of Listeria. Using PCR, hly gene was recognized in eight samples (2%) of L. monocytogenes. Furthermore, there was a significant difference in isolation rate of lamb samples compared to cow ones. While all of the isolates were resistant to clindamycin, amikacin and chloramphenicol, they were sensitive to penicillin.
Conclusion: in spite of low rate of infection in red meat samples in Kerman city, due to high risk of Listeria contamination in red meats, we recommend applying a routine screening to identify this bacterium in our county.
Keywords: Listeria Monocytogenes, Hly Gene, Red Meat, Antibiotic, Kerman
Shima Doostmohammadi , Babak Kheirkhah , Seyed Mohammad Reza Khoshroo ,
Volume 10, Issue 4 (Jul-Aug 2016 2016)
Abstract
ABSTRACT
Background and Objectives: Size of silver nanoparticles synthesized by ethanol and Bacillus lichenioformisis 20 nm and 15 nm, respectively. Nanoparticles can be used in treatment of several diseases. Chemical and biological methods have been used to synthesize silver nanoparticles. The aim of this study was to compare the size, shape and coating of silver nanoparticles synthesized by the chemical and biological methods.
Methods: Ethanol was used in the chemical reduction method and B. licheniformis was used in the biological method. Physical evaluation (salt test), absorbance measurement at 450 nm and imaging by transmission electron microscopy were performed to compare nanoparticles in terms of size, shape and coating.
Results: Observed maroon color, maximum absorption at 400-450 nm range and electron microscopy images confirmed the presence of nanoparticles. The shape of nanoparticles synthesized by the two methods was spherical. However, biosynthesized nanoparticles were smaller and had protein coating.
Conclusion: Given the smaller size of biosynthesized nanoparticles and presence of coating confirmed by the electron microscopy images, biosynthesis is recommended because of enhanced nanoparticles properties and reduced toxicity.
Keywords: Nanoparticles, Coating, Toxicity.
