Welcome to the Microbiology Information

Did you know that according to researchers in Hong Kong more than 10% of imported oysters screened using a reverse transcription polymerase chain reaction (RT-PCR) assay showed evidence of norovirus (Norwalk-like virus) contamination. Senior investigator Dr. Wilina W. L. Lim explains that although the approach is of limited use in demonstrating an epidemiological link with human cases, “it appears that oysters may be an important vehicle for introducing novel strains of norovirus.”

Outbreaks of norovirus gastroenteritis are often associated with consumption of oysters and contamination appears to be widespread, Dr. Lim of the Public Health Laboratory Centre, Kowloon, and colleagues note in the August issue of the Journal of Medical Virology. They found that 10.5% of 507 samples of oysters from 11 countries tested on arrival showed evidence of norovirus contamination. In particular, oysters from six countries were contaminated; those from the remaining five countries were not. A wide variety of strains was found, including two novel genetic clusters.

Norovirus screening was also conducted following 13 outbreaks of oyster-associated gastroenteritis in hotels or restaurants in Hong Kong. Norovirus RNA sequences were detected in at least one oyster in six outbreaks. However, only in one outbreak was there a match between the strains isolated from patients and those found in the oysters.

Dr Lim concludes with “Given the popularity of consuming raw oysters in many countries, oysters may serve (as) a vehicle for the dissemination of new norovirus strains,”

Journal of Medical Virology 2005;76:593-597.

Now here is some interesting news about a new way to eliminate listeria in foods. It uses bacteriophage (viruses) to attack and destroy listeria monocytogenes cells in cheese.

Here’s what they say in the press release:

EBI Food Safety of the Netherlands announced that its bacteriophage P100 preparation, marketed as LISTEX(TM), has been approved as GRAS (Generally Recognized As Safe) by the US FDA, to control Listeria monocytogenes (LM) in cheese. This acknowledgement by the FDA is based on a thorough safety review, and is recognized by food companies and national governments worldwide. GRAS affirmation is an essential step in the commercialization of LISTEX(TM). LISTEX(TM) is the first bacteriophage product to receive GRAS recognition by the FDA. Listeria monocytogenes is generally viewed as the most dangerous food pathogen. It can cause Listeriosis, a fatal disease in roughly 30% of the cases, especially dangerous for newborns, the elderly and persons with weakened immune systems. Listeriosis is also a major concern to pregnant
women, causing spontaneous abortion. In the US, the costs of acute illness from food borne Listeria poisoning alone are estimated at $2.3 billion per year. Expenses for food processing companies to combat Listeria likewise run into the billions.

“In January of this year an independent expert panel of internationally recognized scientists unanimously concluded that LISTEX(TM) meets the GRAS safety requirements. Now that the FDA has given its formal approval, we will make our product available to the US market. The high end market, requesting ‘green’ and organic products, has been asking for LISTEX(TM), but we wanted an official endorsement by the FDA first.” says Mark Offerhaus, CEO of EBI Food Safety. “We are presently negotiating with prospective partners in North America and Europe to find the fastest way to market”. Prevention of food safety defects results in considerable gains of profitability and productivity. Offerhaus: “Food safety and quality systems are not only good corporate policy, they are simply good business. Appropriate use of LISTEX(TM) in food processing as an integral part of HACCP and GMP/GHP programs fits that concept perfectly”.

Source

Now here is some interesting news, a food recall in Australia due to oysters being contaminated with a virus rather than a bacterial pathogen. The recall is due to the norovirus in oyster imported into Australia from Asia.

Interestingly, the testing of food product for norovirus is not common and is technically very difficult. For a public recall to occur due to this virus, it must have come about due to many gastro cases and an intensive investigation. Could there be future lawsuits from this? Who knows?

A similar incident did occur in 2003 when frozen oysters from Japan were implicated. For more information click here

Source

Norovirus
When the word “food pathogens” is mentioned, most will people will associate it with salmonella, E.coli or listeria. Although they are true pathogens, the symptoms they produce are initially similar to a common gastro virus called the norovirus. Viruses are very different from bacteria and parasites. They are not affected by treatment with antibiotics, and they cannot grow outside of a person’s body.

You see, the norovirus is a very common virus that causes nausea, vomiting, diarrhea, and some stomach cramping. Sometimes people also have a low-grade fever, chills, headache, muscle aches, and a general sense of tiredness. The illness often begins suddenly, and the infected person may feel very sick. The illness is usually brief, with symptoms lasting only about 1 or 2 days. In general, children experience more vomiting than do adults. Most people with norovirus illness experience both diarrhea and vomiting.

The main concern is that sometimes people become dehydrated due to vomiting and diarrhea and may need special medical attention. Dehydration problems are usually only seen among the very young, the elderly, and persons with weakened immune systems.

Infection with noroviruses
Noroviruses are found in the stool or vomit of infected people. People can become infected with the virus in several ways, including:

• Eating food or drinking liquids that are contaminated with norovirus;
• Touching surfaces or objects contaminated with norovirus, and then placing their hand in their mouth;
• Having direct contact with another person who is infected and showing symptoms

Persons working in day-care centers or nursing homes should pay special attention to children or residents who have norovirus illness. This virus is very contagious and can spread rapidly throughout such environments. Particular care should be taken with young children in diapers who may have diarrhea or who have vomited as both stool and vomit can carry the virus.

People infected with norovirus are contagious from the moment they begin feeling ill to at least 3 days after recovery. Some people may be contagious for as long as 2 weeks after recovery. Therefore, it is very important to use good hand washing and other hygienic practices.

Treatment for people with norovirus infection?
Currently, there is no antiviral medication that works against norovirus and there is no vaccine to prevent infection. Norovirus infection cannot be treated with antibiotics because antibiotics work to fight bacteria and not viruses.

The comon flu is caused by the Influenza virus and it is a highly contagious viral infection of the nose, throat, and lungs. The flu is one of the most severe illnesses of the winter season. According to the Centers for Disease Control (CDC) in Atlanta, the flu is the fifth leading cause of death in the U.S.

In the US, the Peak Flu season is between December and March with the highest numbers of illnesses reported in February. To protect yourself against the flu and its complications a flu vaccination (flu shot) is required, however not every requires it.

Who Should Get the Flu Shot?
People 65 years of age and older
Children 6 to 23 months old.
Adults and children with chronic health problems.
Women who will be more than three months pregnant during flu season.

Is the Flu Shot Safe?
Contrary to popular belief, you cannot get the flu from the “flu shot.” The vaccine is very safe and generally has few side effects. There may be some soreness, redness, or slight swelling where the shot was given. Some people get a headache or slight fever for a day. But most people have no side effects at all.

How Often Should I Get a Shot?
You need to get a flu shot each year. Why? Because a virus causes the flu and viruses have the ability to change. A new vaccine must be developed each year to match the new virus. About two weeks after your shot, you will have protection against the new flu virus.

How to Know if You Have the Flu!
If you get the flu, symptoms will appear rapidly within hours to a day. A high fever, chills, dry cough, and a headache are common. You may also have a runny nose, congestion, sore throat, aches, and pains. The flu will cause extreme fatigue lasting several days even weeks.

The flu will also last longer than a common cold. While you are sick, try not to put others at risk. The virus is easily spread from person to person. When an infected person coughs, sneezes, or talks, the virus becomes airborne. Others then pick it up.

Severe cases can result in viral or bacterial pneumonia. Illnesses such as congestive heart failure, diabetes, and asthma can worsen during a bout with the flu. The elderly and people who are already sick are more likely to require hospital care.

Self Care with the Flu
Since a virus causes the flu–antibiotics like penicillin do not work to cure it. There are several antiviral drugs available by prescription only. When started within the first two days of illness, they can shorten illness. But they cannot cure it outright.

Bed rest is needed.
Take aspirin or non-aspirin pain releasers to ease muscle aches.
Drink plenty of fluids to help flush the virus out of your system.
Reduce the risk to others by staying at home until you recover.
Practice basic hygiene: wash hands often, cover nose and mouth when you cough or sneeze.
If severe symptoms last more than five days, see a doctor.

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Did you know that enteric viruses such as Hepatitis A virus, norovirus (formally called Norwalk-like virsus), enteroviruses, astroviruses, adenovirus, rotaviruses and Hepatitis E virus have all been implicated in foodborne and waterborne outbreaks with Norovirus being the most common.

Foods that are free from pathogens but is prepared by a person with an enteric virus can still make you sick. You see food handlers must also be aware of that enteric virus are shed in the faeces and during the asymptomatic phases of infection, can easily contaminate foods. A person with an enteric virus such as the contagious Norovirus can vomit or have diarrhoea and can allow the virus to spread through aerosols droplets to the surrounding environment.

The one way to prevent this is good hygiene such as washing you hands with soap and after visiting the toilets, using disinfectants and wearing gloves. The other way of reducing this incident is to ensure the food handler recovers from the illness for at least 48 hours prior to re-starting work. Finally training of personnel in good hygiene is critical in preventing an outbreak.