Your questions about Microbiology and Alpha Scientific answered:

What is Legionella?

Legionella is a pathogenic gram negative bacterium, including species that cause legionellosis (Legionnaires' disease), most notably L. pneumophila. Legionella is common in many environments, with at least 50 species and 70 serogroups identified. Legionella is traditionally detected by culture on buffered charcoal yeast extract (BCYE) agar. Common laboratory procedures for the detection of Legionella in water concentrate the bacteria (by centrifugation and/or filtration through 0.2 micrometre filters) before inoculation onto a charcoal yeast extract agar containing antibiotics (e.g. glycine vancomycimpolymixincyclohexamide, GVPC) to suppress other flora in the sample. Heat or acid treatment is also used to reduce interference from other microbes in the sample.

Where are the Legionella bacteria found?

Legionella bacteria are common in natural water courses such as rivers and ponds.

What is the incubation time for legionella in the laboratory?

The incubation time for legionella in the laboratory is 10 days, a further 2 days may be required if the sample is positive.

What are Total coliforms and E.coli?

Coliform bacteria are commonly found in soil, on vegetation, and in surface waters. They also live in the intestines of warm-blooded animals and humans. Some coliform bacteria strains can survive in soil and water for long periods of time. Coliform bacteria are not likely to cause illness in most people; however, because coliform bacteria are most commonly associated with sewage or surface waters, the presence of coliform bacteria in drinking water indicates that other disease-causing organisms (pathogens) may be present in the water source or its distribution system.

Escherichia coli (commonly referred to as E. coli) is a species of bacteria commonly found in the intestines of humans and animals. There are many different types of E. coli, and while some live in the intestine quite harmlessly, others may cause a variety of diseases. The bacterium is found in faeces and can survive in the environment.

Why should we test for Total Coliforms and E.coli ?

Tests for coliform bacteria and E.coli are the most important routine microbial examinations carried out on drinking water. These tests provide a sensitive means for detecting faecal contamination, for assessing raw water quality, the effectiveness of water treatment and disinfection and for monitoring water quality in distribution.

What is the incubation time for Total Coliforms and E.coli in the laboratory ?

The incubation time for Total Coliforms and E.coli is 18 hours, a further 2 days may be required if the sample is positive.

What are Pseudomonas aeruginosa?

Pseudomonas aeruginosa is a Gram-negative bacterium commonly found in soil and ground water.  It rarely affects healthy people and most community-acquired infections are associated with prolonged contact with contaminated water.

P. aeruginosa is increasingly important clinically as it is a major cause of both healthcare-associated infections and chronic lung infections in people with cystic fibrosis.

Although P. aeruginosa is an opportunistic pathogen (i.e. more likely to infect those patients who are already very sick as opposed to healthy patients), it can cause a wide range of infections, particularly among immunocompromised people (HIV or cancer patients) and persons with severe burns, diabetes mellitus or cystic fibrosis.

What is the incubation time for Pseudomonas aeruginosa in the laboratory ?

The incubation time for Pseudomonas aeruginosa is 48 hours, a further 1 day may be required if the sample is positive.

What are Total Viable Counts (TVCs)?

Total Viable bacteria growing at 37 °C and 22 °C enable a count to be determined of the heterotrophic bacterial population of the water. The bacteria grown in these tests are not indicators of faecal contamination, although historically, the count at 37 °C was taken to give an indication of faecal contamination. In the UK, the rationale for enumerating heterotrophic plate counts has been to assess the general bacterial content of the water and to monitor trends or rapid changes in water quality.

What is Aseptic Technique?

Aseptic techniques are used to attempt to keep samples free of microbial contamination. It is important that steps are taken to eliminate/reduce the possibility of cross contamination occurring between the different sampling operations. When dismantling any equipment that is to be sampled (Shower heads or mixer valves) new disposable gloves should be worn for each piece of equipment.

How do you take a pre flush legionella sample?

A pre flush sample is collected without disinfection and flushing of the outlet. A pre flush sample determines the colonisation of a particular outlet and is the most representative of the risk to individuals.

What is a post flush legionella sample?

A post flush sample is collected after the disinfection and flushing of the outlet. A post flush sample determines whether the system is colonised, as opposed to the outlets. It determines that the numbers of organisms flowing around the system are controlled. This type of post-flush sample is intended to be representative of the quality of the water supplied to the tap or fitting.

What are Endotoxins?

Endotoxins form part of the lipopolysaccharides (LPS) located on the membrane of Gram-negative bacteria, whether these organisms are pathogens or not. LPS’s can be constantly shed into the environment, and will continue to exist even when the parent organism dies. They are resistant to many sanitization agents, and are able to pass through traditional filtration. Good examples of endotoxin producing gram-negative bacteria are Escherichia coli, Proteus, Pseudomonas, Enterobacter, and Klebsiella.

What can Alpha Scientific offer for Sterile Services and Endoscopy?

Within sterile services and endoscopy departments Alpha Scientific can provide a full service from weekly sampling and analysis to the full validation of washers and sterilisers. This is in accordance with the latest guidance and regulations and we work closely with AP’s and Infection Control to ensure that all the latest research and advice is applicable. Alpha Scientific can also provide a full bacterial identification service to establish the type of contamination within the washer and provide antibacterial efficacy testing of the appropriate disinfectant should it be required.

What can Alpha Scientific offer for Renal Dialysis?

Alpha Scientific can provide all the relevant microbiological and chemical testing requirements required to ensure that the ultra pure required for dialysis, including haemodiafiltration, is of the appropriate standard. Alpha Scientific have the most sensitive equipment available to the industry and can provide ultra-low levels of detection for endotoxins.