Abstract/Details

<i>Enterobacter sakazakii</i>: A study on inactivation, detection and virulence


2006 2006

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Abstract (summary)

Enterobacter sakazakii is an emerging pathogen transmitted through contaminated infant formula, causing meningitis, meningo-encephalitis, necrotizing enterocolitis and sepsis in neonates and infants. In spite of the renewed research interest on E. sakazakii in the recent past, many lacunae exist in our understanding of the pathogen, especially regarding how it brings about disease in the host. Development of effective antimicrobial ingredients to prevent growth of E. sakazakii in infant formula would improve the safety of the formula preparations. The present study revealed that monocaprylin, the monoglyceride ester of caprylic acid (C-8 fatty acid) at 50 mM level reduced E. sakazakii count by >5 log CFU/ml by 1 h of incubation at 37 or 23°C, and by 24 h of incubation at 8 or 4°C in reconstituted infant formula. Rapid tools for E. sakazakii detection in infant formula would promote effective monitoring and early detection of contamination of infant formula. A PCR developed using primers based on the outer membrane protein A ( ompA) gene of E. sakazakii was found to be specific to E. sakazakii strains and could detect 10-1 CFU E. sakazakii of per ml of reconstituted infant formula. Identifying the virulence factors of E. sakazakii and delineating their role in the pathogenic mechanism will help us to identify new targets for therapeutic or prophylactic intervention strategies against this pathogen. Outer membrane protein A (OmpA) was identified as a major fibronectin binding protein of E. sakazakii by ligand immuno blotting assay. An isogenic mutant strain in the ompA of E. sakazakii was found to be significantly (P < 0.05) attenuated in its invasiveness into brain microvascular endothelial cells and human intestinal epithelial (INT 407) cells. Complementation of the mutant with the ompA gene restored the invasive phenotype significantly (P < 0.05). The invasiveness of E. sakazakii into INT 407 cells was inhibited by drugs acting on both microfilament and microtubule components of the cytoskeleton. Further, E. sakazakii was found to induce localization of both microfilaments and microtubules in infected INT 407 cells.

Indexing (details)


Subject
Food science;
Microbiology;
Pathology
Classification
0359: Food science
0410: Microbiology
0571: Pathology
Identifier / keyword
Health and environmental sciences; Biological sciences; Antimicrobials; Enterobacter sakazakii; Infant formula
Title
<i>Enterobacter sakazakii</i>: A study on inactivation, detection and virulence
Author
Manoj Kumar, Mohan Nair
Number of pages
177
Publication year
2006
Degree date
2006
School code
0056
Source
DAI-B 67/10, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780542939044
Advisor
Venkitanarayanan, Kumar
University/institution
University of Connecticut
University location
United States -- Connecticut
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3239565
ProQuest document ID
305321545
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305321545
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