Author: Phyllis Entis

Profiling Shigella

Four species of bacteria belong to the genus Shigella – S. boydii, S. dysenteriae, S. flexneri and S. sonnei. All of them are pathogenic.

Some history

Shigella dysenteriae – the species that causes dysentery – was the first Shigella species to be described. It was isolated for the first time from a sample of feces during the investigation of a case of dysentery in 1888.

What is Shigella, and where is its natural habitat?

Shigella causes gastrointestinal infections, including dysentery. Members of this genus produce a toxin known as shiga toxin – similar to the toxin produced by E. coli O157:H7 and other shiga-toxin producing strains of E. coli. Shigella‘s natural habitat is the intestinal tract of humans and primates. Shigella dysenteriae remains the most common of the four species in underdeveloped countries; S. sonnei and S. flexneri are the dominant species in the industrialized world.

How is Shigella transmitted? What is the incubation period of the infection?

Shigella is not typically found in the soil. The disease is transmitted through consuming contaminated food or water (which has been exposed to fecal material that contains Shigella), and by direct or indirect person-to-person contact. Swimming in contaminated water also can be a mode of transmission. The incubation period typically is 24-48 hours.

What illnesses are caused by Shigella? How long does it take to develop?

Depending on the species, an individual infected with Shigella may develop either dysentery or shigellosis, approximately 24-48 hours after becoming infected.

What are the symptoms of Shigella dysentery and shigellosis

Dysentery:- Individuals infected with Shigella dysenteriae will likely suffer from abdominal cramps and frequent, bloody diarrheic stools that also contain mucus.

Shigellosis:- A milder form of illness, characterized by abdominal cramps, fever and diarrhea – sometimes bloody or containing mucus – lasting 4 to 7 days.

What is the prognosis of Shigella infections?

The disease is largely self-limiting in the developed world. Complications that may develop include severe dehydration, Reiter’s syndrome (a form of reactive arthritis) or hemolytic uremic syndrome. In underdeveloped and emerging countries, where malnutrition and poor health are common, shigellosis and dysentery often can be fatal.

What foods carry Shigella?

Food and water may become infected through direct or indirect contact with fecal material from an infected individual.

How can susceptible people protect themselves from infection?

The US Centers for Disease Control and Prevention (CDC) offers the following advice for preventing the spread of Shigella:

  • Wash hands with soap carefully and frequently, especially after going to the bathroom, after changing diapers, and before preparing foods or beverages.
  • Dispose of soiled diapers properly
  • Disinfect diaper changing areas after using them.
  • Keep children with diarrhea out of child care settings.
  • Supervise hand washing of toddlers and small children after they use the toilet.
  • Do not prepare food for others while ill with diarrhea
  • Avoid swallowing water from ponds, lakes, or untreated pools.

For more information on Shigella and other food-borne pathogens, visit the CDC website or read Food Safety: Old Habits, New Perspectives.

Recalls and Alerts: November 3, 2011

Here is today’s list of food safety recalls, product withdrawals, allergy alerts and miscellaneous compliance issues. The live links will take you directly to the official recall notices and company news releases that contain detailed information for each recall and alert.

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United States

  • Allergy Alert: Giant Eagle recalls Cut Out Cookies, 10-ct (UPC 28968500000; All Lots; All Date codes), due to the presence of undeclared milk.
  • Food Recall: Hawaii Candy recalls Hawaii Candy Fortune Cookies (UPC 073366-12950), Petite Wafers (UPC 073366-12952), Sesame Wafers (UPC 073366-12954) and Ginger Wafers (UPC 073366-12955), because the products contain undeclared Yellow #6 as an ingredient.
  • Outbreak Alert: More than 175 children at the Pittsburgh Montessori PreK-8 in Friendship school (Pittsburgh, PA) became ill last week with suspected norovirus gastroenteritis. Seven teachers (nearly one-fourth of the staff) also were absent due to the same illness. The school building was closed on Friday for disinfection. Lab tests are under way to confirm the cause of the illness.
  • Outbreak Alert: Three cases of E. coli infection have been confirmed in Boone County, Missouri. Two more cases are under investigation. County public health officials say that there is no connection to the St. Louis outbreak. Two of the Boone County victims were hospitalized.

Canada

  • Food Safety Recall: Boucherie Fairmount (Montréal, QC) recalls Csabai sausages, because the sausages were not stored in a manner to ensure their safety. The public is advised not to consume this product.
  • Food Safety Recall: CFIA announces the recall of Jones Hot Air Popcorn (2kg; Manufactured by Jones Popcorn), due to the insect contamination.
  • Cosmetic Product Safety Recall: ITN Food Corporation recalls Black Henna Cone and Red Henna Cone (Manufactured in Pakistan; all lots), because the products contain phenol and other phenolic compounds, which can produce chemical burns to the skin. The recalled products were sold at various ethnic stores in Ontario and Quebec from December 2010 to May 2011.
  • Consumer Product Safety Recall: Colgate-Palmolive recalls Colgate Motion Electric Toothbrush (battery-operated), after receiving several reports that the toothbrushes had “exploded.” The company is no longer manufacturing this toothbrush.

Europe

  • Food Safety Alert (UK): The Food Standards Agency (FSA) warns the public that, since August, a high proportion of consignments of paan leaves – also known as betel leaves – imported from Bangladesh and India have been found to be contaminated with Salmonella. As paan leaves typically are chewed raw, this represents a risk of Salmonella food poisoning. At the request of FSA, local port authorities are sampling and testing all consignments of paan leaves presented for import.
  • Food Recall (Belgium): Colruyt and OKay recall several lots of Everyday U.H.T. milk, 1L boxes, including whole milk, part-skim milk and skim milk, following customer complaints concerning taste and odor. Please refer to the recall notice for details of the affected production lots.
  • Food Recall (Belgium): Carrefour recalls Carrefour Discount brand Whole Milk (1L carton; Lot #111678, 111724 and 111732), due to off-taste or unusual odor.
  • Food Advisory: Delhaize advises its customers that certain boxes of the following milk may, in time, develop an altered taste or odor, due to a sporadic technical malfunction at the manufacturer: Delhaize 365 Ecrémé lait (Lot 111891 and 111892; Expiry 28/01/2012).

Asia, Africa and the Pacific Islands

  • Food Safety Alert (Singapore): The Agri-Food & Veterinary Authority of Singapore advises the public that Società cooperativa agricola G.M.G F. ar.l. dei F.lli Gaudiano, Italy, has, as a precautionary measure, initiated a market recall of all batches and sizes of olives stuffed with almonds dated from 2010 and 2011. This was because two cases of botulism found in Finland has been linked to the consumption of the olives. There is no import of the affected products into Singapore. Nevertheless, AVA advises consumers who have bought the implicated products, whilst overseas, to discard the products and not to consume them.

Australia and New Zealand

  • Allergy Alert (New Zealand): Bon-Soy recalls Bon-Soy Phyto-Nutraceutical soy milk powder (500g; all batches) and Bon-Rice Phyto-Nutraceutical rice milk powder (450g; all batches), due to the presence of undeclared casein, a milk protein. Please refer to the recall notice for a list of stores where the products were sold.
  • Food Safety Recall (Australia): Charlie’s Group Australia Pty Ltd. recalls Phoenix Ginger Beer (330ml; Best Before 22/08/12), Phoenix Creaming Soda (330ml; Best Before 22/08/12), Phoenix Cola Cluster Pack (4 x330ml; Best Before 22/08/12), Phoenix Orange Fizz (330ml; Best Before 23/08/12), Phoenix Sparkling Apple (300ml; Best Before 23/08/12), and Phoenix Sparkling Blood Orange (300ml; Best Before 23/08/12), because some of the bottles were inadequately pasteurized. As a result, the contents of some bottles may ferment, increasing the risk of shattering.
  • OTC Pharmaceutical Product Safety Recall (Australia): Colgate-Palmolive Pty Ltd recalls Savacol Antiseptic Mouth & Throat Rinse Alcohol Free chlorhexidine gluconate 2 mg/mL mouthwash bottle (manufactured by Gaba International AG Active, Switzerland; All unexpired batch numbers), due to microbial contamination.

Some supermarket chains post recall notices on their web sites for the convenience of customers. To see whether a recalled food was carried by your favorite supermarket, follow the live link to the supermarket’s recall web site.

*The Kroger umbrella encompasses numerous supermarket, marketplace and convenience store chains, listed on the Kroger corporate home page.
**Includes Safeway, Vons, Pavilions, Dominick’s, Genuardi’s, Randalls, Tom Thumb, Carrs and Pak N’ Save.

Investigators Need A Break In St. Louis E. coli O157:H7 Outbreak

Local, state and federal investigators are scratching their heads and hoping for a break as they try to identify the source of an outbreak of E. coli O157:H7 that has sickened at least 26 people in and around St. Louis, Missouri since October 25th. At least 19 outbreak victims have been hospitalized.

According to the Washington Post, the outbreak victims range in age from 1 to 94, and live in St. Louis city and four surrounding counties – St. Louis, Jefferson and St. Charles counties in Missouri, and St. Clair county in Illinois. The Illinois Department of Public Health acknowledged on October 28th that it was investigating a single illness in St. Clair County that might be linked to the Missouri outbreak.

The Missouri Department of Health and Senior Services is testing samples from an additional 25 suspect cases as part of the investigation into the outbreak, which appears to be linked to food sold from supermarket salad bars. At least some of the suspect salad bar components were supplied by distributors or processors outside of the state of Missouri, and FDA has been called in to assist in the inspection of the individual links in the distribution chain.

Initial patient interviews appeared to point to Schnucks Markets, Inc. salad bars as a common link. Schnucks is a regional supermarket chain headquartered in St. Louis, with Schnucks stores located in Missouri, Illinois, Indiana, and Iowa, and Logli/Hilander stores located in Rockford, Illinois and Janesville, Wisconsin.

Based on the initial information obtained from patients, Schnucks removed certain items from all of its salad bars, and replaced the items with products obtained from other suppliers. None of the items sampled so far from Schnucks salad bars or from the homes of patients have yielded E. coli.

After an additional round of patient interviews, a further 38 food samples have been collected from five Schnucks stores and submitted to the State lab for testing. These new samples include Bistro Salad Dressing, broccoli florets, deviled eggs, diced hard-boiled eggs, honey Dijon dressing, Italian dressing, pineapple chunks, red wine vinaigrette, shredded carrots, shredded radishes, shredded zucchini, and sliced red onions. In addition, six packaged salads that contain salad bar ingredients were submitted for analysis: Bistro Chopped Salad, Fresco House Salad, Fried Chicken Salad, Garden Salad, Italian Salad, and Turkey Cobb Salad.

The U.S. Centers for Disease Control and Prevention (CDC) has been called upon to assist in the epidemiological investigation, and is carrying out a case control study. The study will compare foods eaten by confirmed outbreak patients with foods consumed by a control group of healthy individuals living in the same area. With judicious questioning – and with some luck – the case control study might be successful in identifying one or more probable food sources for the outbreak.

Salad bar-related outbreaks can be especially difficult to trace to a source, due to the sheer number of different items present, and the potential for cross-contamination from serving utensils or the dropping of one salad bar item into another. Small salad ingredients, such as sliced vegetables, cherry tomatoes, and sprouts are especially susceptible to landing in the wrong bin. And people often don’t remember every vegetable or garnish that they selected.

Another complication in this outbreak investigation is the short shelf life of salad ingredients. The contaminated component may no longer be in the distribution chain. The longer it takes for a possible food to be identified via patient interviews and the case control study, the less likely it becomes that the contaminated food will be identified.

The State has not provided any time-related breakdown of the reported cases, so it’s difficult to tell whether or not the outbreak has reached its peak. Consumers in the St. Louis metropolitan area and surrounding counties should be especially careful in purchasing and handling salad items while this outbreak continues.

Public health officials in Missouri are urging anyone experiencing gastrointestinal symptoms, such as severe stomach cramps, diarrhea or nausea to seek medical attention.