scholarly journals Growth interferences between bacterial strains from raw cow's milk and their impact on growth of Listeria monocytogenes and Staphylococcus aureus

2021 ◽  
Author(s):  
J. Hahne ◽  
A. Lipski
Keyword(s):  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Cow’S Milk ◽  
Bacterial Strains ◽  
Cow's Milk ◽  
And Staphylococcus Aureus ◽  
Raw Cow’S Milk

scholarly journals Effect of an Italian propolis on the growth of Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus in milk and whey cheese

2019 ◽  
Vol 8 (4) ◽  
Author(s):  
Francesca Pedonese ◽  
Giada Verani ◽  
Beatrice Torracca ◽  
Barbara Turchi ◽  
Antonio Felicioli ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Listeria Monocytogenes ◽  
Bacillus Cereus ◽  
Dairy Products ◽  
Skim Milk ◽  
Cow’S Milk ◽  
Alcoholic Extract ◽  
Cow's Milk

Propolis antimicrobial activity has been limitedly studied in food, particularly in dairy products. We studied the antimicrobial activity of an alcoholic extract of an Italian propolis in sterile skim milk, pasteurized cow’s milk, and cow’s and goat’s whey cheese (ricotta). Following the determination of the minimal inhibitory concentration on Gram+ and Gram- bacteria, the extract was employed at 2 and 5% (P2, P5), using controls with the same ethanol concentrations (E2, E5) and without any addition. In milk trials, Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, and Pseudomonas fluorescens were tested. P2 and P5 samples registered significant decreases of Gram+ bacteria in skim milk. The same was true for P5 in cows’ milk, but only with S. aureus for P2. Ricotta was inoculated with L. monocytogenes, S. aureus and B. cereus and stored at 8.5°C. In cow’s milk ricotta, L. monocytogenes counts in P5 were always lower than control during the storage time, significantly so from the 14th day. In goat’s ricotta, L. monocytogenes counts in P5 were at least one logarithm lower than E5, whereas the extract didn’t show a significant effect on S. aureus and B. cereus. The antimicrobial activity of propolis, particularly on L. monocytogenes, could be employed in ready-to-eat refrigerated dairy products.

scholarly journals Prevalence of Listeria monocytogenes in Raw Cow's Milk in the Region of Batna, Algeria

2021 ◽  
Vol 16 (4) ◽  
pp. 212-216
Author(s):  
Sabrina Rabehi ◽  
Bakir Mamache ◽  
Taha Mossadak Hamdi ◽  
Asma Meghezzi ◽  
Khaoula Boushaba
Keyword(s):  
Listeria Monocytogenes ◽  
Cow’S Milk ◽  
Cow's Milk ◽  
Raw Cow’S Milk

scholarly journals Characterization of Antibacterial Lactic Acid Bacteria Isolated from Moroccan fermented Olives

2017 ◽  
Vol 14 (4) ◽  
pp. 1315-1329 ◽  
Author(s):  
Kaoutar El issaoui ◽  
Sanae Zinebi ◽  
Jamal Abrini ◽  
Rajae Zahli ◽  
Nadia Amajoud ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Inhibitory Effect ◽  
Bacterial Strains ◽  
Table Olives ◽  
Gram Positive ◽  
Gram Negative ◽  
And Staphylococcus Aureus

The research for antibacterial activities of lactic acid bacteria isolated from Moroccan table olives, revealed 15 bacterial strains having an inhibitory activity against pathogenic germs: Listeria monocytogenes, Listeria innocua and Staphylococcus aureus; as well as Gram-negative germs, such as Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and others. From 127 samples of table olives, 143 bacterial strains with antibacterial effect were isolated by the double layer method, 15 strains were retained. All are Gram positive, catalase negative and non-sporulating. Cocci constitute 66.33% of the total effective. The remaining 33.33% are represented by bacilli/Ovoid. The lactic acid bacteria retained have a greater inhibitory effect against Gram positive and Gram negative bacteria. Listeria monocytogenes CECT 4032 and Staphylococcus aureus MBLA were inhibited by all the lactic strains studied. The smallest inhibition zones were recorded for the two isolates LB15 and LB96 against E. coli 87739, with diameter less than 10 mm.

scholarly journals Intracellular Accumulation of Linezolid and Florfenicol in OptrA-Producing Enterococcus faecalis and Staphylococcus aureus

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3195 ◽  
Author(s):  
Yingyu Wang ◽  
Xiaowei Li ◽  
Yang Wang ◽  
Stefan Schwarz ◽  
Jianzhong Shen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Enterococcus Faecalis ◽  
High Performance ◽  
Resistance Mechanism ◽  
Bacterial Strains ◽  
Quadrupole Mass ◽  
Active Efflux ◽  
Antibiotic Efflux ◽  
And Staphylococcus Aureus ◽  
Tandem Quadrupole

The optrA gene, which confers transferable resistance to oxazolidinones and phenicols, is defined as an ATP-binding cassette (ABC) transporter but lacks transmembrane domains. The resistance mechanism of optrA and whether it involves antibiotic efflux or ribosomal protection remain unclear. In this study, we determined the MIC values of all bacterial strains by broth microdilution, and used ultra-high performance liquid chromatography-tandem quadrupole mass spectrometry to quantitatively determine the intracellular concentrations of linezolid and florfenicol in Enterococcus faecalis and Staphylococcus aureus. Linezolid and florfenicol both accumulated in susceptible strains and optrA-carrying strains of E. faecalis and S. aureus. No significant differences were observed in the patterns of drug accumulation among E. faecalis JH2-2, E. faecalis JH2-2/pAM401, and E. faecalis JH2-2/pAM401+optrA, but also among S. aureus RN4220, S. aureus RN4220/pAM401, and S. aureus RN4220/pAM401+optrA. ANOVA scores also suggested similar accumulation conditions of the two target compounds in susceptible strains and optrA-carrying strains. Based on our findings, the mechanism of optrA-mediated resistance to oxazolidinones and phenicols obviously does not involve active efflux and the OptrA protein does not confer resistance via efflux like other ABC transporters.

Comparison of Four Commercial DNA Extraction Kits for PCR Detection of Listeria monocytogenes, Salmonella, Escherichia coli O157:H7, and Staphylococcus aureus in Fresh, Minimally Processed Vegetables

2008 ◽  
Vol 71 (10) ◽  
pp. 2110-2114 ◽  
Author(s):  
P. ELIZAQUÍVEL ◽  
R. AZNAR
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Dna Extraction ◽  
Pcr Detection ◽  
Escherichia Coli O157 ◽  
Minimally Processed ◽  
Green Pepper ◽  
Minimally Processed Vegetables ◽  
And Staphylococcus Aureus

Four commercial DNA extraction methods, PrepMan Ultra (Applied Biosystems), InstaGene Matrix (BioRad), DNeasy Tissue kit (Qiagen), and UltraClean (MoBio), were tested for PCR detection of Listeria monocytogenes, Escherichia coli O157: H7, Salmonella, and Staphylococcus aureus in fresh, minimally processed vegetables. For comparative purposes, sensitivity assays with specific PCRs were carried out after DNA extraction with the four methods in green pepper, broccoli, and onion artificially inoculated with the four pathogens separately. As confirmed by statistical analysis, the DNeasy Tissue kit rendered the highest sensitivity values in the three matrices assayed for Salmonella, L. monocytogenes, and E. coli O157:H7 and in onion for S. aureus. Despite being the most expensive of the methods compared, the DNeasy Tissue Kit can be successfully applied for any of the four most commonly studied pathogens, thus saving time and overall reducing the cost of the analysis.

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