Oponentní posudek diplomové práce Emy Jančářové „Use of silver containing compounds as bacteriocides in dimethacrylate based dental materials“
Diplomová práce Emy Jančářové, vypracovaná pod vedením prof. RNDr.Vladimíra Vetterla, DrSc., zapadá svým obsahovým zaměřením do problematiky studia modifikace existujících dentálních materiálů sloučeninami s bakteriocidními účinky. Cílem práce bylo prověřit možnosti modifikace pryskyřic, používaných ve stomatologii, pomocí sloučenin obsahujících stříbro a otestovat jejich vlastnosti, přičemž na testování jako modelový mikroorganizmus byl zvolen kmen Streptococcus mutants CCM P2093, izolovaný z dutiny ústní. Tato problematika je velmi aktuální, protože je známé, že ve stomatologii používané kompozitní dentální materiály adherují ve zvýšené míře bakterie osídlující tvrdé tkáně v dutině ústní. Práce je rozčleněna do čtyř kapitol. Po krátkém úvodu (Kapitola 1) je v Kapitole 2. na 32 stranách uveden literární přehled současného stavu poznatků v oblasti, souvisejících s řešenou problematikou. Experimentální část je obsažena v Kapitole 3, dosažené experimentální výsledky a jejich následná diskuze jsou prezentovány v rámci Kapitoly 4. V práci je uvedeno 66 citací. Práce je napsána přehledně a srozumitelně, s minimálním množstvím překlepů. Rovněž kvalita anglického textu a grafická úprava diplomové práce je na dobré úrovni..
K práci mám následující připomínky a otázky:
1. Literární zdroje jsou nepřesně a nejednotně citovány.
2. V „Teoretické části“ na str. 30 citace v podkapitole 2.5.3. poslední odstavec literatura [38] nesouhlasí s uvedenou literaturou v odkazech. Předpokládám, že z literárního zdroje [38] byla převzata metoda na stanovení bílkovin.
3. Při uvedení názvu mikroorganizmu je nutné uvést i akronym sbírky odkud byl získánStreptococcus mutants CCM P2093 . Jinak práce jako vědecká informace nemá význam.
4. V „Experimentální části“ na str. 45 chybí postup při stanovení kalibrační křivky, která je uvedena na obr.33. Prosím doplnit a vysvětlit, proč grafické vyjádření kalibrační křivky je nelineární.
5. V kapitole „Výsledky a diskuze“ nejsou obrázky uspořádány chronologicky. Například po obrázku č. 56 na str. 54, následuje obrázek č. 46 na str. 56, přičemž obr.č. 46 je velmi nepřehledný vzhledem k textu na str.55. a textu pod obrázkem č.46. Prosím doplnit a vysvětlit.
6. V kapitole „Výsledky a diskuze“
autorka používá neobvyklou terminologii pro popis
v mikrobiologii. Prosím vysvětlit termín „ planktonic growth“ (str. 61).
7. Lze vzhledem k získaným výsledkům v budoucnu uvažovat o použití takto modifikovaných pryskyřic ve stomatologii ?
Závěr: Předložená diplomová práce Emy Jančářové představuje cenný příspěvek k studiu problematiky vlastností dentálních materiálů. Na základě prezentovaných experimentálních výsledků je možné konstatovat, že autorka diplomové práce splnila cíle, které si postavila na začátku jejího vypracování. Několik připomínek oponenta nemá zásadní vliv na celkové pozitivní hodnocení předložené práce. Z těchto důvodů hodnotím diplomovou práci posluchačky známkou.
„velmi dobře (B)“
V Brně dne 25. 5. 2008
doc. Ing. Jiřina Omelková, CSc. .
Title: Detection of Enterobacter sakazakii strains by real-time PCR Author(s): Malorny B, Wagner M Source: JOURNAL OF FOOD PROTECTION 68 (8): 1623-1627 AUG 2005 Document Type: Article Language: English Cited References: 22 Times Cited: 0 Abstract: A precise 5' nuclease (TaqMan) real-time PCR was developed and validated in house for the specific detection of Enterobacter sakazakii isolates. Specifically designed nonpatented primers and a hydrolysis (TaqMan) probe were used to target the 16S rRNA gene. All 27 E. sakazakii and 141 non-E. sakazakii strains tested with the real-time PCR were identified correctly. To monitor false-negative results, an internal amplification control was coamplified with the same primers used for the E. sakazakii DNA. The detection probability of the assay was 56% when an E. sakazakii cell suspension containing 10(2) CFU/ml was used as template in the PCR (0.5 CFU per reaction) and 100% with a 10(3) CFU/ml suspension. This PCR assay should be very useful for the diagnostic detection of E. sakazakii in foods, especially powdered infant formula, after cultural enrichment. KeyWords Plus: DIAGNOSTIC PCR; MILK FORMULA; SALMONELLA; AMPLIFICATION; ACCURACY; QUALITY; SAMPLES; FOOD Addresses: Malorny B (reprint author), Fed Inst Risk Assessment, Diedersdorfer Weg 1, Berlin, D-12277 Germany Fed Inst Risk Assessment, Berlin, D-12277 Germany Inst Milk Hyg Milk Technol & Food Sci, Vienna, A-1210 Austria E-mail Addresses:
[email protected] Publisher: INT ASSOC FOOD PROTECTION, 6200 AURORA AVE SUITE 200W, DES MOINES, IA 50322-2863 USA Subject Category: BIOTECHNOLOGY & APPLIED MICROBIOLOGY; FOOD SCIENCE & TECHNOLOGY IDS Number: 953BQ ISSN: 0362-028X Author(s): Edelson-Mammel SG, Porteous MK, Buchanan RL Source: JOURNAL OF FOOD PROTECTION 68 (9): 1900-1902 SEP 2005 Document Type: Article Language: English Cited References: 18 Times Cited: 0 Abstract: A quantity of dehydrated powdered infant formula was prepared to contain Enterobacter sakazakii strain 607 at approximately 10(6) CFU/ml when rehydrated according to the manufacturer's instructions. The survival of the microorganism in the dry formula was followed for 2 years, during which samples periodically were rehydrated and analyzed for viable E. sakazakii. During the initial 5 months of storage at room temperature, viable counts declined approximately 2.4 log cycles. During the subsequent 19 months, the concentration of viable E. sakazakii declined an additional 1.0 log cycle. These results indicate that a small percentage of E. sakazakii cells can survive for extended periods in dehydrated powdered infant formula. KeyWords Plus: NEONATAL MENINGITIS; INFECTIONS; MILK; CONTAMINATION; OUTBREAK Addresses: Buchanan RL (reprint author), USDA, Ctr Food Safety & Appl Nutr, 5100 Paint Branch Pkwy, College Pk, MD 20740 USA
USDA, Ctr Food Safety & Appl Nutr, College Pk, MD 20740 USA Univ Maryland, Joint Inst Food Safety & Appl Nutr, College Pk, MD 20740 USA E-mail Addresses:
[email protected] Publisher: INT ASSOC FOOD PROTECTION, 6200 AURORA AVE SUITE 200W, DES MOINES, IA 50322-2863 USA Subject Category: BIOTECHNOLOGY & APPLIED MICROBIOLOGY; FOOD SCIENCE & TECHNOLOGY IDS Number: 961VV ISSN: 0362-028X Title: Application and acceptability of three commercial systems for detection of Enterobacter sakazakii in ready-to-eat vegetable salads Author(s): Weiss C, Becker B, Holzapfel W Source: ARCHIV FUR LEBENSMITTELHYGIENE 56 (2): 34-38 MAR-APR 2005 Document Type: Article Language: German Cited References: 8 Times Cited: 0 Abstract: Enterobacteriaceae are considered to be the main cause of spoilage in plant products. Especially ready-to-eat vegetable salads are highly contaminated with these bacteria. Already the raw products used for the production of mixed salads show high microbiological counts whilst no significant reduction is achieved by technical means during processing. Some Enterobacteriaceae, for example Enterobacter sakazakii, represent a serious health risk for weak and elderly persons, infants, immunocompromised persons and those with chronical illness. For this reason, reliable identification of this species is most important. Different methods are available for the phenotypic identification of Enterobacter sakazakii. In this study, three commercial systems for the biochemical identification of Enterobacteriaceae were used: the Api(R) 20E-System (bioMerieux(R) Deutschland GmbH), the Microbact(TM) 24E-System (OXOID GmbH Deutschland) and the Biolog-System (Biolog Inc. USA). The objective of this study was a comparative identification of 109 isolates of Enterobacteriaceae from 72 samples of mixed salads, packed in plastic bags or trays, as well as the assessment of the systems used for identification. The occurrence and frequency of detection of Enterobacter sakazakii in ready-to-eat salads was to be determined. 19 strains of the 109 isolates were identified as Enterobacter sakazakii with the Api 20ESystem. However, these identifications could not be confirmed by the other systems. Subsequently, 18 of the 19 strains were examined by additional tests. The proof of pigment formation at 25 degrees C on tryptone-soy-agar did not bring any clarity. A final identification was achieved only with the BAX(R) Detection System (DuPont Qualicon) and the special testkit for Enterobacter sakazakii, showing that none of the 18 strains belonged to Enterobacter sakazakii. KeyWords Plus: SERVE SALADS Addresses: Weiss C (reprint author), Bundesforschungsanstalt Ernahrung & Lebensmittel, Standort Karlsruhe, Inst Hyg & Toxikol, Haid & Neu Str 9, Karlsruhe, D-76131 Germany Bundesforschungsanstalt Ernahrung & Lebensmittel, Standort Karlsruhe, Inst Hyg & Toxikol, Karlsruhe, D-76131 Germany E-mail Addresses:
[email protected] Publisher: M H SCHAPER GMBH CO KG, BORSIGSTRASSE 5, POSTFACH 16 42, 310460 ALFELD, GERMANY Subject Category: CHEMISTRY, APPLIED; FOOD SCIENCE & TECHNOLOGY; TOXICOLOGY IDS Number: 932ZZ ISSN: 0003-925X Title: Rapid, specific detection of Enterobacter sakazakii in infant formula using a realtime PCR assay Author(s): Seo KH, Brackett RE Source: JOURNAL OF FOOD PROTECTION 68 (1): 59-63 JAN 2005 Document Type: Article
Language: English Cited References: 11 Times Cited: 0 Abstract: Enterobacter sakazakii is a rare cause of invasive infection with high mortality rates in neonates. Powdered milk-based infant formulas have been associated with the E. sakazakii-related outbreaks in premature or other immunocompromised infants. In this study, an assay was developed for the specific detection of E. sakazakii in infant formula using an application of the fluorogenic 5' nuclease assay (TaqMan). A set of primers and probe was designed using the E. sakazaki, partial macromolecular synthesis operon: the rpsU gene 3' end and the primase (dnaG) gene 5' end. The specificity of the. assay was evaluated using 68 Enterobacter and 55 non-Enterobacter strains. The newly developed assay enables us to detect 100 CFU/ml in pure culture and in reconstituted infant formula in 50 cycles of PCR without enrichment. The assay was specific enough to discriminate E. sakazakii from all other Enterobacter and non-Enterobacter strains tested. The developed real-time PCR assay could save up to 5 days and eliminate the need for plating samples on selective or diagnostic agars and for biochemical confirmation steps. The real-time PCR assay could be used to rapidly screen infant formula samples for L sakazakii and would be a boon to food industries and regulatory agencies. KeyWords Plus: OPERON; OUTBREAK Addresses: Seo KH (reprint author), US FDA, Ctr Food Safety & Appl Nutr, Off Plant & Dairy Foods & Beverages, 5100 Paint Branch Pkwy, College Pk, MD 20740 USA US FDA, Ctr Food Safety & Appl Nutr, Off Plant & Dairy Foods & Beverages, College Pk, MD 20740 USA E-mail Addresses:
[email protected] Publisher: INT ASSOC FOOD PROTECTION, 6200 AURORA AVE SUITE 200W, DES MOINES, IA 50322-2863 USA Subject Category: BIOTECHNOLOGY & APPLIED MICROBIOLOGY; FOOD SCIENCE & TECHNOLOGY IDS Number: 886ZU ISSN: 0362-028X
Title: 16S rRNA gene based analysis of Enterobacter sakazakii strains from different sources and development of a PCR assay for identification Author(s): Lehner A, Tasara T, Stephan R Source: BMC MICROBIOLOGY 4: Art. No. 43 NOV 25 2004 Document Type: Article Language: English Cited References: 16 Times Cited: 0 Abstract: Background: E. sakazakii is considered to be an opportunistic pathogen, implicated in food borne diseases causing meningitis or enteritis especially in neonates and infants. Cultural standard identification procedures for E. sakazakii include the observation of yellow pigmentation of colonies and a positive (α) over tilde glucosidase activity. Up to now, only one PCR system based on a single available 16S rRNA gene sequence has been published for E. sakazakii identification. However, in our hands a preliminary evaluation of this system to a number of target and non-target strains showed significant specificity problems of this system. In this study full-length 16S rRNA genes of thirteen E. sakazakii strains from food, environment and human origin as well as the type strain ATCC 51329 were sequenced. Based on this sequence data a new specific PCR system for E. sakazakii was developed and evaluated. Results: By phylogenetic analysis of the new full-length 16S rRNA gene sequence data obtained we could show the presence of a second phylogenetic distinct lineage within the E. sakazakii species. The newly developed 16S rRNA gene targeting PCR system allows identification of E. sakazakii strains from both lineages. The assay's ability to correctly identify different E. sakazakii isolates as well as to differentiate E. sakazakii from other closely related Enterobacteriaceae species and other microorganisms was shown on 75 target and non-target strains. Conclusion: By this study we are presenting a specific and reliable PCR identification system, which is able to correctly identify E. sakazakii isolates from both phylogenetic distinct lines within the E. sakazakii species. The impact of this second newly described phylogenetic line within the E. sakazakii species in view of clinical and food safety aspects need further investigation. KeyWords Plus: POWDERED MILK; FORMULA; INFECTIONS; SLUDGE Addresses: Stephan R (reprint author), Univ Zurich, Fac Vet, Inst Food Safety & Hyg, Zurich, CH-8057 Switzerland Univ Zurich, Fac Vet, Inst Food Safety & Hyg, Zurich, CH-8057 Switzerland E-mail Addresses:
[email protected],
[email protected],
[email protected] Publisher: BIOMED CENTRAL LTD, MIDDLESEX HOUSE, 34-42 CLEVELAND ST, LONDON W1T 4LB, ENGLAND Subject Category: MICROBIOLOGY IDS Number: 880KD ISSN: 1471-2180
