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Necidova L.,University of Veterinary And Pharmaceutical Sciences Brno | Janstova B.,University of Veterinary And Pharmaceutical Sciences Brno | Karpiskova R.,University of Veterinary And Pharmaceutical Sciences Brno | Karpiskova R.,National Institute of Public Health Prague
Acta Veterinaria Brno | Year: 2012

The aim of this study was to evaluate the impact of internal factors (pH, NaCl) and external factors (temperature, incubation time) on the ability of Staphylococcus aureus to grow and to produce staphylococcal enterotoxins SEA, SEB, and SEC. The fresh cheese environment was modelled in Brain Heart Infusion Broth media and food matrices (pasteurized milk from retail outlets) by internal and external factors (pH = 4.5 and 5.5, 2% NaCl, and t = 8 °C and 15 °C). The counts of enterotoxigenic strains of S. aureus at baseline, i.e. at the time of inoculation of model samples, corresponded to those encountered in the production of fresh cheeses as a result of post-pasteurization contamination. Enumeration of S. aureus was performed in accordance with EN ISO 6888-1, using agar medium. Staphylococcal enterotoxins were detected by the enzyme-linked fuorescence assay. The pH (4.5) and refrigeration temperature (8 °C) used prevented S. aureus from achieving the critical count of 105 cfu·ml-1 specifed in Commission Regulation (EC) No. 2073/2005. The highest rates of enterotoxin production were recorded for enterotoxin A. The growth curves of S. aureus derived from model experiments were compared with the growth curve generated by a predictive microbiology program - Pathogen Modelling Program. The results of this study proved the Pathogen Modelling Program to be suitable for use in the Hazard Analysis Critical Control Points system in the process of the fresh cheese production to help manufacturers prevent the growth of S. aureus and enterotoxin production.

Gelbicova T.,National Institute of Public Health Prague | Karpiskova R.,University of Veterinary And Pharmaceutical Sciences Brno
Chemicke Listy | Year: 2011

Internalin A, encoded by the gene inlA, is the key virulence factor, which allows crossing the intestinal barrier during the initial stages of an infection. The aim of this study was to evaluate the potential of RFLP (restriction fragment length polymorphism) technique of inlA for monitoring the occurrence of potentially invasive strains of L. monocytogenes from different sources. The ability to invade the epithelial host cells of the intestinal barrier was detected in 52.3% of the investigated strains. RFLP profiles (1and 4) associated with the production of truncated form of the internalin A and with the decreased invasiveness was detected only in serotype 1/2a and 1/2c. These RFLP profiles were found in strains isolated from food (43.6%) and the external environment (66.7%), but also in some human strains (42.1%). Following the inlA polymorphism by PCR-RFLP is a fast screening technique for evaluation of alteration in pathogenic potential of L. monocytogenes.

Cidlinova A.,Czech University of Life Sciences | Cidlinova A.,National Institute of Public Health Prague | Zimova M.,Czech University of Life Sciences | Zimova M.,National Institute of Public Health Prague | And 4 more authors.
12th International Multidisciplinary Scientific GeoConference and EXPO - Modern Management of Mine Producing, Geology and Environmental Protection, SGEM 2012 | Year: 2012

Arsenic (As) contamination was investigated in urban soil agglomerates in the Czech Republic. The aim of studying surface urban soil layers was to assess the degree of health risk resulting from the exposure to toxic substances through unintended consumption of soil and soil dust. Given that the greatest risk of increased exposure is for the population of pre-school children, the project focused on kindergarten playgrounds. Measurements were carried out in a total of 413 kindergartens in 38 towns. Selected metals and polycyclic aromatic hydrocarbons were monitored in the surface soil layer samples of the playgrounds. This study presents the results As contamination of the soil and evaluates the health risks faced by children through exposure to these soils. Based on the results of the soil analysis and on the use of residential exposure scenarios for pre-school children, the oral exposures to As in children within the 1 to 6 year age group were estimated. At all monitored sites the risk was found to be higher than 1x10-6. When the overall risk of cumulative exposure to As during childhood and adulthood was evaluated, the risk of 1x10-6 was exceeded in about 99% of the cases and the risk of 1x10-5 was exceeded in about 54% of the cases. © SGEM2012 All Rights Reserved by the International Multidisciplinary Scientific GeoConference SGEM.

Gelbicova T.,National Institute of Public Health Prague | Gelbicova T.,Masaryk University | Karpiskova R.,National Institute of Public Health Prague | Karpiskova R.,University of Veterinary And Pharmaceutical Sciences Brno
Czech Journal of Food Sciences | Year: 2012

We monitored the presence of Listeria monocytogenes in environmental sources and to evaluate the phenotypic and molecular characteristics of the isolates recovered. L. monocytogenes was isolated in 12 (11.2%) of the 107 samples from the wild, farm environment, and vegetation. Most isolates (83.3%) were of serotype 1/2a and the remainder (2) were of serotype 4b. All 12 isolates were susceptible to the whole range of antimicrobials tested. These12 strains were carriers of the virulence genes prfA, hlyA, actA, plcA, plcB, inlA, inlB, inlC, and inlJ. The detection of the inlA gene in 4 (33.3%) of 12 strains using the PCR-RFLP suggests the potential of some of these strains to penetrate into epithelial cells of the intestinal barrier. Macrorestriction analysis also confirmed clonal identity of some environmental isolates with food and human isolates. These results indicate that the external environment is a source of potentially pathogenic strains of L. monocytogenes.

Stastkova Z.,University of Veterinary And Pharmaceutical Sciences Brno | Karpikova R.,University of Veterinary And Pharmaceutical Sciences Brno | Karpikova R.,National Institute of Public Health Prague | Gelbicova T.,University of Veterinary And Pharmaceutical Sciences Brno | And 4 more authors.
Acta Alimentaria | Year: 2012

Milk and dairy products can be frequently contaminated with enterotoxigenic Staphylococcus aureus which is often involved in staphylococcal food poisoning. The aims of this study were to study the occurrence of S. aureus in bulk tank milk samples and to test their potential to produce staphylococcal enterotoxins (SEs). A total of 511 bulk tank milk samples were collected from 305 farms in 9 different regions of the Czech Republic. S. aureus was detected in 199 (38.9%) samples. The S. aureus positivity rates varied with sample origin (farm) and ranged from 0 to 67%. The potential to produce enterotoxins A-J was confirmed in 89 (44.7%) of 199 S. aureus isolates. The most commonly detected genes were seg (35.2%) and sei (31.7%). Both genes were detected in 23% of the isolates. Other genes detected were seb (in 5.0% of enterotoxin-positive isolates), seh (5.0%), sed (4.0%), sec (2.5%) and sej (0.5%). The variation in the rates of toxigenic isolates can be attributed primarily to the colonization of farms by specific clones of S. aureus.

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