Application of a virulent bacteriophage cocktail leads to reduction of Salmonella enterica serovar Enteritidis counts in processed meat products

ABSTRACTSalmonellosis represents a worldwide health problem because it is one of the major causes of food-borne disease. Although motility is postulated as an importantSalmonellavirulence attribute, there is little information about variation in motility in natural isolates. Here we report the identification of a point mutation (T551 → G) inmotA, a gene essential for flagellar rotation, in severalSalmonella entericaserovar Enteritidis field isolates. This mutation results in bacteria that can biosynthesize structurally normal but paralyzed flagella and are impaired in their capacity to invade human intestinal epithelial cells. Introduction of a wild-type copy ofmotAinto one of these isolates restored both motility and cell invasiveness. ThemotAmutant triggered higher proinflammatory transcriptional responses than an aflagellate isolate in differentiated Caco-2 cells, suggesting that the paralyzed flagella are able to signal through pattern recognition receptors. A specific PCR was designed to screen for the T551 → G mutation in a collection of 266S. Enteritidis field isolates from a nationwide epidemic, comprising 194 from humans and 72 from other sources. We found that 72 of the 266 (27%) isolates were nonmotile, including 24.7% (48/194) of human and 33.3% (24/72) of food isolates. Among nonmotile isolates, 15 carried the T551 → G mutation and, significantly, 13 were recovered from food, including 7 from eggs, but only 2 were from human sources. These results suggest that the presence of paralyzed flagella may impair the ability ofS. Enteritidis to cause disease in the human host but does not prevent its ability to colonize chickens and infect eggs.

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An Ultrasound Assessed Extraction Combined with Ion-Pair HPLC Method and Risk Assessment of Nitrite and Nitrate in Cured Meat

Journal of Analytical Methods in Chemistry ◽

10.1155/2018/1907151 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6 ◽

Cited By ~ 3

Author(s):

Babiker Yagoub Abdulkair ◽

Amin O. Elzupir ◽

Abdulaziz S. Alamer

Keyword(s):

Risk Assessment ◽

Tetrabutylammonium Bromide ◽

Meat Products ◽

Correlation Coefficients ◽

Dietary Exposure ◽

Hplc Method ◽

Processed Meat ◽

Disodium Hydrogen Phosphate ◽

Cured Meat

An accurate IPC-UV method was developed and validated for the determination of nitrite (NI) and nitrate (NA) in meat products. The best separation was achieved on a phenyl-hexyl column (150 mm × 4.6 mm, 3 µm) with a mobile phase composed of 25% acetonitrile and 75% buffer (2 mM disodium hydrogen phosphate and 3 mM tetrabutylammonium bromide, pH = 4). Eluents were monitored at 205 nm. Linearity ranges were 1.86 × 10−6–7.5 µg·ml−1 and 0.09–5.0 µg·ml−1 for NI and NA, respectively. The correlation coefficients were greater than 0.999 for NI and NA. This method was applied to a number of processed meat products in Riyadh (n = 155). NI ranged from 1.78 to 129.69 mg·kg−1, and NA ranged from 0.76 to 96.64 mg·kg−1. Results showed extensive use of NI and NA; however, concentrations were within the legal limit of Saudi Arabia except for one sample. Further, the risk assessment and dietary exposure have been estimated for both NI and NA.

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Survival characteristics of Salmonella enterica serovar Enteritidis in chicken egg albumen

Epidemiology and Infection ◽

10.1017/s0950268806006054 ◽

2006 ◽

Vol 134 (5) ◽

pp. 967-976 ◽

Cited By ~ 44

Author(s):

H. KANG ◽

C. LOUI ◽

R. I. CLAVIJO ◽

L. W. RILEY ◽

S. LU

Keyword(s):

Salmonella Enterica ◽

Iron Acquisition ◽

Foodborne Pathogen ◽

Human Infection ◽

Salmonella Enterica Serovar Enteritidis ◽

Factors Affecting ◽

Chicken Egg ◽

Egg Albumen ◽

High Concentrations ◽

Incubation Temperatures

Salmonella enterica serovar Enteritidis (SE) is a major foodborne pathogen primarily causing human infection through contaminated chicken eggs. To understand how SE survives in chicken egg albumen, we systematically and quantitatively analysed the survival properties of SE in egg albumen and identified factors affecting its survival. Survival assays of SE in egg indicate that egg albumen restricted the growth of SE. A major factor that controlled SE's growth in egg albumen was iron restriction, since egg albumen supplemented with iron allowed SE to grow, and iron acquisition mutants of SE showed decreased survival in egg albumen. In addition, low pH of albumen, high concentrations of bacteria and low incubation temperatures of bacteria with albumen facilitates the survival of SE. Our results suggest that egg albumen uses multiple mechanisms to control SE including iron limitation, surface interaction and possible enzymatic activities.

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Occurrence and Survival of Verocytotoxin-Producing Escherichia coli O157 in Meats Obtained from Retail Outlets in The Netherlands

Journal of Food Protection ◽

10.4315/0362-028x-62.10.1115 ◽

1999 ◽

Vol 62 (10) ◽

pp. 1115-1122 ◽

Cited By ~ 51

Author(s):

A. E. HEUVELINK ◽

J. T. M. ZWARTKRUIS-NAHUIS ◽

R. R. BEUMER ◽

D E. de BOER

Keyword(s):

Escherichia Coli ◽

The Netherlands ◽

Meat Products ◽

Storage Period ◽

Processed Meat ◽

Raw Meat ◽

Pork Products ◽

Minced Beef ◽

Beef Products ◽

Meat Samples

In 1996 and 1997, 2,941 fresh and processed meat products obtained from supermarkets and butcher shops in The Netherlands were examined for the presence of verocytotoxin-producing Escherichia coli of serogroup O157 (O157 VTEC). Additionally, the fate of O157 VTEC in raw meat products stored at low temperatures and the effect of different additives were evaluated. O157 VTEC strains were isolated from 6 (1.1%) of 571 samples of raw minced beef, 2 (0.5%) of 402 samples of raw minced mixed beef and pork, 1 (1.3%) of 76 samples of raw minced pork, 1 (0.3%) of 393 samples of other raw pork products, and 1 (0.3%) of 328 samples of cooked or fermented ready-to-eat meats. Other raw beef products (n = 223) and meat samples originating from poultry (n = 819), sheep or lamb (n = 46), or wild animals (n = 83) were all found to be negative for O157 VTEC. For the survival experiments we used tartaar (minced beef with a fat content of less than 10%) and filet americain (tartaar mixed with a mayonnaise-based sauce [80 to 20%]). The O157 VTEC strain tested was able to survive in tartaar and filet americain stored at −20, 0, 5, or 7°C for 3 days. At both 7 and at 15°C, O157 VTEC counts in tartaar and filet americain remained virtually unchanged throughout a storage period of 5 days. Addition of acetic acid (to pH 4.0), sodium lactate (1 and 2% [wt/wt]), or components of the lactoperoxidase–thiocyanate–hydrogen peroxide system to filet americain did not result in a reduction of viable O157 VTEC cells during storage at 7 or 15°C. It was concluded that raw meat contaminated with O157 VTEC will remain a hazard even if the meat is held at low or freezing temperatures.

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Cloning of Salmonella enterica Serovar Enteritidis Fimbrial Protein SefA as a Surface Protein in Escherichia coli Confers the Ability To Attach to Eukaryotic Cell Lines

Applied and Environmental Microbiology ◽

10.1128/aem.00639-09 ◽

2009 ◽

Vol 75 (20) ◽

pp. 6622-6625 ◽

Cited By ~ 6

Author(s):

Douglas L. Rank ◽

Mahdi A. Saeed ◽

Peter M. Muriana

Keyword(s):

Escherichia Coli ◽

Salmonella Enterica ◽

Expression Vector ◽

Surface Protein ◽

Surface Expression ◽

Eukaryotic Cell ◽

Salmonella Enterica Serovar Enteritidis ◽

Western Blot Assay ◽

E Coli ◽

Fimbrial Protein

ABSTRACT The gene for the Salmonella enterica serovar Enteritidis fimbrial protein SefA was cloned into an Escherichia coli surface expression vector and confirmed by Western blot assay. E. coli clones expressing SefA attached to avian ovary granulosa cells and HEp-2 cells, providing evidence for the involvement of SefA in the ability of Salmonella to attach to eukaryotic cells.

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