List of Articles listeriosis

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  1 - Investigating the prevalence of resistance genes in Listeria monocytogenes isolated from food samples
  Mohammad Reza  Saebi Fahimeh nourbakhsh Hossein Khodabandeh shahraki
  Listeria monocytogenes (L. monocytogenes) is a type of pathogenic bacteria that causes listeriosis infection. This facultative anaerobic bacterium is able to survive in the presence and absence of oxygen and is the cause of a wide range of diseases in humans and animals More

  Listeria monocytogenes (L. monocytogenes) is a type of pathogenic bacteria that causes listeriosis infection. This facultative anaerobic bacterium is able to survive in the presence and absence of oxygen and is the cause of a wide range of diseases in humans and animals. Consumption of contaminated dairy products, meat and vegetables is the most important source of contamination. There are limited studies of the antibiotic resistance of Listeria monocytogenes species. Therefore, this study aims to evaluate the frequency and level of resistance in the evaluated samples. In this descriptive cross-sectional study, 150 different samples were randomly collected from different regions of Isfahan province. The samples included 60 samples of meat, 40 samples of dairy products (including milk, cheese, etc.) and 50 samples of vegetables (including leek, watercress, radish and basil). The serotyping of the isolated strains was done using the commercial O and H antisera of Listeria monocytogenes and according to the manufacturer's instructions, using slide agglutination method and antibiotic resistance evaluation. Standard PCR method was used to detect ermA, ermB, strA, tetS, tetA and ermC genes in the strains. Based on the serological reaction, somatic antigens O and flagella H of Listeria monocytogenes with the corresponding antisera, most Listeria species (70%) belong to serotype 1.2a and the rest from serotype 1.2b (19%) and 4b (11 %) They were. The results of the microbial investigation showed that the highest drug resistance was related to streptomycin (89%) and the lowest drug resistance in the evaluated isolates was related to ampicillin (14%) and chloramphenicol (13%). The most evaluated genes were related to strA gene and ermA gene, with frequencies of 79.8% and 65.4%, respectively. The prevalence of other Listeria monocytogenes genes evaluated in this study included tetA (17%), tetS (2.5%), ermB (10.7%) and ermC (2.1%). Manuscript profile
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  2 - Efficacy of microencapsulated nisin with sodium alginate and chitosan on biofilm formation in Listeria monocytogenes
  S. Babakhani Farzaneh Hosseini P. Pakzad M. Bikhof Torbati
  10.30495/jfh.2022.1962616.1363
  Listeria monocytogenes is a foodborne pathogen the cause of listeriosis that has long-term survival due to biofilm formation. This study aimed to investigate the efficacy of nisin 102 IU/ml, encapsulated nisin with chitosan and sodium alginate on biofilm formation and c More

  Listeria monocytogenes is a foodborne pathogen the cause of listeriosis that has long-term survival due to biofilm formation. This study aimed to investigate the efficacy of nisin 102 IU/ml, encapsulated nisin with chitosan and sodium alginate on biofilm formation and changing the expression level of genes related to biofilm formation L. monocytogenes ATCC 19115 (serotype 4b) was treated by nisin 102 IU/ml and microencapsulated nisin with chitosan and sodium alginate solutions. The effectiveness of nisin on cell survival was estimated by calculating the optical absorbance. After proving the presence of prfA, sigB, and agrA genes, the effect of 102 IU/ml nisin dilution on L. monocytogenes biofilm was investigated by the microtiter plate method. The expression level of prfA, sigB, and agrA genes was analyzed using real-time PCR methods (qRT-PCR). The inhibition rate of biofilm formation in L. monocytogenes by nisin 102 IU/ml was 57% at 37°C and pH 5.5. The maximum inhibition of biofilm formation was related to the simultaneous use of nisin 102 IU/ml with chitosan and sodium alginate at 37°C and pH 5.5. Microencapsulated nisin with chitosan and sodium alginate can increase its effectiveness in preventing the biofilm formation of L. monocytogenes to 76% (p<0.0001). Nisin 102 IU/ml decreased the expression level of prfA, sigB, and agrA by -2.313, -2.808, and -1.453-fold compared to the control (p<0.0001). Nisin only had significant inhibitory activity against L. monocytogenes biofilm. Microencapsulated nisin with chitosan and sodium alginate had high efficacy in preventing the biofilm formation of L. monocytogenes.Listeria monocytogenes is a foodborne pathogen the cause of listeriosis that has long-term survival due to biofilm formation. This study aimed to investigate the efficacy of nisin 102 IU/ml, encapsulated nisin with chitosan and sodium alginate on biofilm formation and changing the expression level of genes related to biofilm formation L. monocytogenes ATCC 19115 (serotype 4b) was treated by nisin 102 IU/ml and microencapsulated nisin with chitosan and sodium alginate solutions. The effectiveness of nisin on cell survival was estimated by calculating the optical absorbance. After proving the presence of prfA, sigB, and agrA genes, the effect of 102 IU/ml nisin dilution on L. monocytogenes biofilm was investigated by the microtiter plate method. The expression level of prfA, sigB, and agrA genes was analyzed using real-time PCR methods (qRT-PCR). The inhibition rate of biofilm formation in L. monocytogenes by nisin 102 IU/ml was 57% at 37°C and pH 5.5. The maximum inhibition of biofilm formation was related to the simultaneous use of nisin 102 IU/ml with chitosan and sodium alginate at 37°C and pH 5.5. Microencapsulated nisin with chitosan and sodium alginate can increase its effectiveness in preventing the biofilm formation of L. monocytogenes to 76% (p<0.0001). Nisin 102 IU/ml decreased the expression level of prfA, sigB, and agrA by -2.313, -2.808, and -1.453-fold compared to the control (p<0.0001). Nisin only had significant inhibitory activity against L. monocytogenes biofilm. Microencapsulated nisin with chitosan and sodium alginate had high efficacy in preventing the biofilm formation of L. monocytogenes. Manuscript profile
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  3 - Effects of chitosan nanoparticles on mice infected with Listeria monocytogenes
  Sara Kazemi Rad Mirsassan Mirpour Mehdi Assmar Mohamad Reza Razavi
  10.30495/bioem.2024.2003875.1024
  Listeria monocytogenes is the cause of listeriosis, which has many complications, especially in pregnant women. Due to the antibiotic resistance of this bacterium, many attempts have been made to introduce different medicinal compounds, including nanoparticles based on More

  Listeria monocytogenes is the cause of listeriosis, which has many complications, especially in pregnant women. Due to the antibiotic resistance of this bacterium, many attempts have been made to introduce different medicinal compounds, including nanoparticles based on biological compounds. This research aimed to examine the mechanism of the effect of chitosan nanoparticles on L. monocytogenes in vivo (in the body of a living organism). The standard strain of L. monocytogenes (ATCC 7644) was prepared and analyzed in the Day Hospital Laboratory (Iran). The bacteria were examined based on biochemical tests. Then, the antibacterial activity of concentrations of 4.88 to 5000 µg/mL of chitosan nanoparticles against L. monocytogenes standard (ATCC 7644) was calculated with the investigated methods and the lowest inhibitory and bactericidal concentrations (MIC and MBC, respectively). The effects of different nanoparticle concentrations and ampicillin in mice infected with bacteria were also investigated. In infected mice, the therapeutic effect increased with increasing the nanoparticle concentration, and the concentration of 156.25 /mL was the most effective compared to other treatments. Also, ampicillin chitosan nanoparticles with a concentration of 39.06 g/mL had almost the same therapeutic effect. With the timely identification of listeria contamination in pregnant women and the proper use of chitosan nanoparticles instead of common drugs, a new solution can be found for the treatment of listeriosis. Manuscript profile
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  4 - Pathological report of Listerial meningoencephalitis in sheep
  میثم Hashem zadeh سعید Khalaj zadeh جعفر Yadi کیومرث Amini
    In spring of 2012,two ewes of a sheep flock from west region of Alborz province with neurological disorders as circling,dullness,depression,incoordination and anorexia  were referred to veterinary school hospital of Islamic Azad University of Karaj branch.o More

    In spring of 2012,two ewes of a sheep flock from west region of Alborz province with neurological disorders as circling,dullness,depression,incoordination and anorexia  were referred to veterinary school hospital of Islamic Azad University of Karaj branch.on initial examination,cantral nervous system lesions were suspected.in order to confirm the diagnosis,one of them utanaized.macroscopic findings in necropsy were leptomeningial opacity,cloudy cerebrospinal fluid and meningeal vessels congestion.many foci of yellow-brown discoloration (0.1 mm in diameter) were seen in brain stem section.microscopically,neuronal necrosis,gliosis,perivascular cuffing,neutrophilic micro abscesses and meningoencephalitis were observed.listeria monocytogenes was isolated from brain samples and CSF in bacteriological Lab.on the basis of macroscopic signs,histopathological findings and microbiological test results,meningoencephalic listeriosis was detected in these cases.   Manuscript profile