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Showing 2 results for Irajian
Volume 4, Issue 3 (Summer 2018)
Abstract
Aims: Diagnosis of Listeria monocytogenes infections is critical for epidemiological study and prevention of diseases. This study aimed at identifying L. monocytogenes isolates, using Loop-Mediated Isothermal Amplification Method (LAMP).
Materials & Methods: Listeria strains were obtained from clinical and seafood specimen. All listeria strains were identified by standard microbiological and biochemical tests. The LAMP assay was performed at 65°C with a detection limit of 2.5 ng/μl for 46 min. Specific primers for the hylA gene were used to identify L. monocytogenes. The specificity of the assay was assessed, using DNA from L. monocytogenes ATCC 7644 and L. ivanovii ATCC 19119 and non-Listeria strains. Sensitivity of the LAMP assay was compared with polymerase chain reaction (PCR) method. Amplification LAMP products were visualized via calcein and manganous ions as well as agarose gel electrophoresis.
Findings: A total of 191 samples were obtained, including clinical and food samples. Then, 21 (10.9%) isolates were recovered from specimens. The LAMP results showed high sensitivity (97.2%) and specificity (100 %). The LAMP assay was higher sensitive than of the PCR assay.
Conclusion: This data showed that this method could be used as a sensitive, rapid, and simple identification tool for diagnosis of L. monocytogenes isolates and it may be suitable for epidemiological study plans.
E. Abdollahzadeh, S.m. Ojagh , H. Hosseini , H. Ghaemi , Gh. Irajian ,
Volume 7, Issue 1 (Winter 2018)
Abstract
Aims: Essential oils are a complex of volatile compounds obtained from different parts of plants. Cinnamon (Cinnamomum zeylanicum) essential oil (EO) is known as a suitable source of antibacterial compounds. The aim of present study was to investigate the antibacterial activity of cinnamon EO and ZnO nanoparticles (NPs) against 2 strains of Listeria monocytogenes.
Materials & Methods: In this experimental study, 2 strains of L. monocytogenes (a standard strain and a fish isolated strain) were used. The antibacterial activity of cinnamon EO and ZnO NPs was assessed by well diffusion test. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of cinnamon EO and ZnO NPs were also determined using broth macrodilution method. Moreover, the antibacterial properties of cinnamon EO and ZnO NPs were investigated in a liquid medium. The data were analyzed by SPSS 19 software, using one-way ANOVA and Tukey's post hoc tests.
Findings: The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of cinnamon EO were 16µl/ml and 64µl/ml, respectively. Furthermore, the MIC and MBC of ZnO NPs were 12.5mg/ml and 25mg/ml, respectively. The bacterial population significantly decreased with increasing the ZnO NPs and the cinnamon EO concentrations (p<0.05) and during cold storage, there were significant differences between the 2 strains.
Conclusion: Cinnamon essential oil and ZnO nanoparticles have strong antimicrobial effects against L. monocytogenes, so that the cinnamon essential oil shows bacteriostatic effects on Listeria, but ZnO nanoparticles show bactericidal effect.
