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1 Coping with plate debris in colony counting
The analysis of agar plates for colonies in microbiology is frequently made challenging by the presence of debris and other unwanted material, either embedded within or on the surface of the agar. For manual counting, depending upon the level of experience of the individual involved, this can cause problems in terms of counting errors and loss of valuable laboratory time. In a busy laboratory environment, such activities can waste many hours of otherwise profitable working time during each day.
2 ProtoCOL provides accurate GLP compliant results for fast assessment of anti-microbial therapies in clinical trials
With the rush to get new anti-microbial therapies on the market to treat biological terrorism threats such as anthrax, methods of saving time at the clinical trial stage without compromising on accuracy are becoming increasingly important. Many new treatments for diseases caused by bacteria or yeasts concentrate on reducing or removing these micro-organisms from the affected area. Since colony enumeration provides the data on which product efficacy for most anti-microbial therapies is based, it is essential to obtain the most precise colony counts possible.
3 ProtoCOL - the essential tool for microbial quality control
Many microbial QC departments have a small team of people and yet are faced with the prospect of having to examine thousands of food samples every year for common contaminants such as Salmonella, E.coli 0157, Bacillus cereus, Listeria monocytogenes and Campylobacter. The majority of these samples prove negative with around 99.9 per cent being pathogen free. However, in a food poisoning outbreak a QC department has to test a large number of samples very quickly to help pinpoint the source of contamination. This is to ensure that those infected can be given the most effective treatment and the offending food can be withdrawn from sale to prevent further cases occurring.
4 Rapid quality control of viral vaccines
Internationally, a large number of adults and children are routinely vaccinated to protect them against a range of diseases. Many of these vaccines consist of an inactivated strain of a virus that causes the disease. If the concentration of the viral vaccine is incorrect then the protection may be insufficient, which could prove fatal among some of the more vulnerable groups inoculated. In the case of influenza vaccines, the tests for vaccine concentration must also be performed quickly because there is little time available to produce and test the vaccine before the next influenza season begins.
5 Automating quality control of milk
Across the developed world, billions of gallons of milk are destroyed every year due, in part, to microbial contamination problems. Most dairy QC laboratories test for a range of microorganisms including E.coli, indicating faecal contamination, Psychrophilic bacteria (these break down milk proteins to produce putrid and off flavours) and more dangerous pathogens such as Listeria monocytogenes, a causal agent of bacterial meningitis. The laboratories also test for Mycoplasma, Staphylococcus, Streptococcus and Pseudomonas spp., which are all indicative of mastitis in the dairy herd. If milk is infected with significant numbers of any of these organisms, it is destroyed to protect public health.
6 Automated colony counting for molecular biologists
Transformation efficiency is a measure of the amount of cells within the baceterial culture that are able to take up DNA molecules. Some applications such as the construction of genomic libraries require that the bacteria have a high transformation efficiency. Counting of recombinant colonies is one criteria used to calculate transformation efficiency.
A common method for selecting recombinants involves altering the antibiotic resistance, eg, resistance to ampicillin or tetracycline, cells that contain the vector (plasmid) will survive and cells which do not contain the vector (plasmid) will not survive. Another method is to use a vector (plasmid) such as pUC which has a LacZ gene present. By inserting DNA within the LacZ gene this will inactivate this gene and colonies will remain white. Plasmids which do not contain the inserted DNA will have an active LacZ gene present producing blue colonies.
7 Maintaining sterility in pharmaceutical manufacturing
At major pharmaceutical manufacturing facilities, microbiology Quality Control (QC) departments are responsible for testing tens of thousands of samples per month. These samples, often from several sites, are used to assess the sterility levels of, for example, the air in the plant or the water used to produce the pharmaceuticals. Most pharma companies operate an index system of acceptable levels of contamination, based on established international quality standards. This index ranges from 1 c.f.u (colony forming unit) /ml in critical samples such as the pharmaceutical products to 100 c.f.u/ml in the water used for production.
8 How to validate an aCOLyte automated colony counter to ensure accuracy in a quality control environment
Colony counts provide the data on which the effectiveness of essential products such as anti-microbial drug treatments or bactericidal disinfectants is based. Therefore, when quality controlling these products, it is vital to accurately enumerate colonies.
9 Using ProtoCOL for rapid assessment of the OPKA assay
Streptococcus pneumoniae is a major cause of pneumonia in young children and the elderly. New vaccines against this bacterium are required because conventional antibiotics are becoming less effective due to the increasing numbers of multi drug-resistant S. pneumoniae. To evaluate novel pneumococcal vaccines, an enzyme-linked immunosorbent assay (ELISA) is commonly used alongside a modified in vitro opsonophagocytic-killing assay (OPKA). The ELISA method allows antibody quantitation but cannot distinguish between functional and non-functional antibodies. The OPKA is useful as an additional test for measuring antibody function and is a good surrogate assay for immune protection. Patient blood samples are taken before and after vaccination, serially diluted and tested by OPKA and plated out onto Todd-Hewitt agar plates with yeast extract. An agar overlay containing antibiotics and 2, 3, 5-triphenyl tetrazolium chloride dye is added and the resulting red bacterial colonies are counted the next day to determine the dilution of patient serum that kills 50% of bacteria compared to the control (no serum). This method evaluates the killing function of the antibody induced following vaccination. Multiplexing is possible by use of antibiotic resistant strains of S. pneumoniae.
10 Measurement of reaction zones on large bioassay plates - an automated solution using the AutoZONE system
Manually measuring reaction zones on bioassay plates is a time consuming, yet essential part of determining antibiotic or vaccine potencies. There is an increasing requirement for an easy to use automated zone reader. With AutoZONE, any antibiotic or vaccine manufacturer is guaranteed to attain results of unparalleled accuracy and repeatability, in a fraction of the time and cost of generating manual measurements.
11 Pour plate colony counting
Pour plate colony counting is an application commonly performed in the food, water, dairy, environmental, clinical, research and pharmaceutical laboratories worldwide. The ProtoCOL system provides automatic counting of bacteria on these types of plates.
12 Spiral plate colony counting
Spiral plating is used in the food and pharmaceutical industries. Laboratories requiring to quantitatively determine the number of total viable counts of a large number of food samples often use a spiral plate counter. The spiral plating method uses a dispensing stylus that deposits a syringe drawn sample onto a rotating agar plate in a spiral pattern. The ProtoCOL system provides automatic counting of bacteria on these types of plates.
13 Ames test plate colony counting
The Ames test is a screening test that measures the capability of a chemical substance to cause genotoxicity in specific strains of the bacterium salmonella that carry mutations in the genes involved in histidine synthesis, so that they require histidine for growth. The Ames test is widely used and in particular in the pharmaceutical, food and industrial chemical industries.
14 OPKA assay plate colony counting
The opsonophagocytic killing assay (OPKA) is a useful addition to the pneumococcal antibody enzyme-linked immunosorbent assay (ELISA). The in-vitro OPKA for pneumococcal antibodies should predict immune protection and be a good surrogate assay for immune protection induced by the vaccine.
15 AST plate zone counting
Antibiotic susceptibility testing (AST) is a disk diffusion test commonly used in the pharmaceutical industry and in veterinary medicine. This test is used to determine the sensitivity or the resistance of a specific antibiotic to provide patient specific treatment.
16 SRD plate zone counting
The single radial diffusion (SRD) test is a commonly used technique in the pharmaceutical industry for determining vaccine potency. The SRD test provides a quantitative method for determining the concentration of the antigen present in the test sample.
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