Welcome to the Microbiology Information

Pseudomonas aeruginosa is a gram -ve rod shaped bacterium that is naturally found in many types of drinking water. According to European water regulations, it is a requirement to have Pseudomonas aeruginosa absent in a 250 ml sample of bottled water. Unfortunately no such regulation exists in the United States and other developed countries. Apparently, the Pseudomonas aeruginosa regulation in Europe originated as a quality control issue and not as a health effects issue.

Interestingly during the last 10 years, there have been an increase in the number of papers appearing indicating that Pseudomonas aeruginosa from drinking water is a health threat. This can only happen if the levels are high.

Being psychrotrophic, a food microbiologist will think it’s more a food spoilage issue than a health threat. The clinical microbiologist will think it is an opportunistic bacterium and can lead to a health threat. So where does this bacterium come from?

Pseudomonas aeruginosa is a ubiquitous environmental bacterium. It can be recovered, often in high numbers, in common food, especially vegetables. Moreover, it can be recovered in low numbers in drinking water. A small percentage of clones of Pseudomonas aeruginosa possess the required number of virulence factors to cause infection. As an opportunistic bacterium, Pseudomonas aeruginosa will not proliferate on normal tissue but requires previously damaged organs.

By further narrowing down the risk to human health, only certain specific hosts are at risk. They include patients with profound neutropenia, cystic fibrosis, severe burns, and those subject to foreign device installation. Other than these very well defined groups, the general population is normally immune to infection with Pseudomonas aeruginosa.

Although it is ubiquitous nature, there are ways to eliminate Pseudomonas aeruginosa from our food and drinking water. They include cooking foods properly, filtering or boiling drinking water.

If you are interesting in finding out the levels of Pseudomonmas aeruginosa in your water supply for food, I suggest you contact a reputable water microbiology laboratory.

Severe Infections Caused by Pseudomonas Aeruginosa. Perspectives on Critical Care Infectious Diseases, Band 7 Severe Infections Caused by Pseudomonas aeruginosa emphasizes controversies worldwide in the diagnosis, treatment, prevention and pathogenesis of pseudomonas aeruginosa infections. By including both chapters written by European authors and chapters written by North American experts, the reader is ensured of receiving a broad spectrum of opinions on controversial topics. Special attention is paid to such topics as the diagnosis of hospital-acquired pneumonia caused by p. aeruginosa, scheduled antibiotic therapy for patients with cystic fibrosis, empiric therapy for febrile neurotropenic patients, combination vs. single agent antibiotic therapy for severely ill patients, and alternatives to conventional antibiotic therapies. This excellent overview of our current understanding of pseudomonas aeruginosa pathogenesis will prove useful to clinicians and microbiologists around the globe. TOC:Contributors.- Preface.- Series Preface.- 1. Pseudomonas aeruginosa Infections in Specific Types of Patients and Clinical Set, Medical / Nursing ; infectious & contagious diseases ; medical microbiology & virology ; Infectious Diseases ; Microbiology, Severe Infections Caused by Pseudomonas Aeruginosa. Perspectives on Critical Care Infectious Diseases, Band 7

Legionella are bacteria that are common in the environment such as rivers and lakes as well as artificial water systems which includes hot and cold water systems such as storage tanks, pipework, taps and showers. In the environment the occurrence of legionella in groundwater is also common.

With Legionella we usually associate it with larger water systems such as those in factories, hotels, hospitals and museums, and cooling towers. However, they can also live in smaller water supply systems used in homes and other residential accommodation.

In addition, other potential sources of legionella include spa and whirlpool baths, humidifiers in factories and fire-fighting systems such as sprinklers and hose reels. Legionella can survive in
low temperatures, but thrive at temperatures between 2OoC and 45oC. At high temperatures, greater than 6O0C legionella will be killed.

Legionella causes Legionnaires’ disease and it is a potentially fatal form of pneumonia. It can affect anybody, however the risk is higher for those over 45 years of age, smokers and heavy drinkers, those suffering from chronic respiratory or kidney disease, and people whose immune system is low or impaired.

Legionellosis is the collective name given to the pneumonia-like illnesses caused by legionella bacteria, including the most serious and well-known Legionnaires’ disease, and also the similar but less serious conditions of Pontiac fever and Lochgoilhead fever.

If you suspect an area may have the potential for Legionella, then it is best to get the water tested using an accredited water testing laboratory.

Testing for Vibrio parahaemolyticus is relevant to seafoods only. High levels of Vibrio parahaemolyticus (>100 per gram) in cooked seafoods indicates that the food has been inadequately cooked or cross-contaminated after cooking with subsequent time/temperature abuse and should result in an investigation of the food handling controls used by the food business.

Higher levels (up to 100 per gram) of Vibrio parahaemolyticus in raw seafoods may be expected because of natural contamination from the aquatic environment, however levels from 1000 to 10000 per gram in raw seafoods would indicate inadequate temperature controls since harvesting and should be considered as unsatisfactory.

The potentially hazardous level of Vibrio parahaemolyticus relates to Kanagawa-positive strains. Levels of Vibrio parahaemolyticus of ≥10000 cfu per gram are considered potentially hazardous as consumption of the food may result in food borne illness (relates to Kanagawa-positive strains).

The Microbiology of Safe Food No Synopsis Available

Did you know that it is possible for you to assess the legionella risk yourself. Below are a list of questions you can go through if you do not feel you have the right skills. Alternatively, you can obtain help and advice from a consultant and use them as a form of training.

When you do the risk assessment, consider the following:

1. Are the conditions right for the bacteria to multiply, for example is the water temperature between 20oC and 45oC? This is the ideal temperature growth range?

2. Are there areas where stagnant water occurs (deadlegs), for example pipes to a washing machine or any other appliance that use water and is no longer used? Again growth can occur in stagnant water.

3. Are there infrequently used outlets, for example showers and/or taps?

4. Is there debris in the system, such as rust, sludge or scale (often a problem in old metal cisterns), that could provide food for growing legionella? Remember iron is a substrate used for growth of legionella.

5. Are there thermostatic mixing valves that set a favourable outlet temperature for legionella growth?

6. Are any of your employees, residents, visitors etc vulnerable to infection, eg heavy smokers, older people, or those with low immune system?

If you answered ‘yes’ to any of these questions, I suggest there is an increased risk of your premises being exposed to legionella and may be a risk.

Did you know that bacteria are not the only cause food poisoning outbreaks. There are other microorganims out here that can produce similar symptoms. These are the protozoan pathogens and they include Giardia, Cryptosporidium and Cyclospora. All have been associated with several foodborne outbreaks.

Protozoan are single-celled, microscopic animals that reproduce in the intestinal tract of the host (eg humans and animals). As part of their life cycle, they produce eggs (cyst or oocyst), which is part of their reproductive cycle and helps them to spread and reproduce. These eggs are excreted in the faeces and are extremely infectious through water or food. With the majority being waterborne, they are found in sewage, lakes and ponds. Although rare, swimming pools and possibly the drinking water could a source. The only way to find if they are present is to test for them using water microbiology laboratory.

If you are infected with these protozoans (intestinal tract), it causes the following symptoms: Watery diarrhoea, fever, muscle aches, abdominal cramps, nausea and vomiting. Symptoms can last for months.

Researchers have revealed that anthrax spores may survive traditional drinking water disinfection methods, according to a Feb. 17 American Society for Microbiology (ASM) press release.

Researchers convened recently at the 2006 ASM Biodefense Research Meeting to determine the fate of anthrax spores in a drinking water system that uses chlorine as a disinfectant, the release said.

According to the statement, the report suggests that water treatment facilities should be prepared to employ alternate disinfection methods (such as exposure to higher concentrations of chlorine or an alternate disinfectant for an extended period of time) in the unlikely event of the release of anthrax into the water supply.

“The data seem to suggest that anthrax spores can tolerate water treatment, can attach to pipes or biofilms within the pipes, and could pass through pipe systems to reach the consumer tap,” Jon Calomiris of the Air Force Research Laboratory at Aberdeen Proving Ground, Edgewood, MD, said in the release.

Source: WaterTechOnline