An agar plate is a Petri dish that contains a growth medium solidified with agar, used to culture microorganisms. Sometimes selective compounds are added to influence growth, such as antibiotics.
Bacteriological water analysis is a method of analysing water to estimate the numbers of bacteria present and, if needed, to find out what sort of bacteria they are. It represents one aspect of water quality. It is a microbiological analytical procedure which uses samples of water and from these samples determines the concentration of bacteria. It is then possible to draw inferences about the suitability of the water for use from these concentrations. This process is used, for example, to routinely confirm that water is safe for human consumption or that bathing and recreational waters are safe to use.
Coliform bacteria are defined as either motile or non-motile Gram-negative non-spore forming bacilli that possess β-galactosidase to produce acids and gases under their optimal growth temperature of 35–37 °C. They can be aerobes or facultative aerobes, and are a commonly used indicator of low sanitary quality of foods, milk, and water. Coliforms can be found in the aquatic environment, in soil and on vegetation; they are universally present in large numbers in the feces of warm-blooded animals as they are known to inhabit the gastrointestinal system. While coliform bacteria are not normally causes of serious illness, they are easy to culture, and their presence is used to infer that other pathogenic organisms of fecal origin may be present in a sample, or that said sample is not safe to consume. Such pathogens include disease-causing bacteria, viruses, or protozoa and many multicellular parasites.
Eosin methylene blue is a selective stain for Gram-negative bacteria. EMB contains dyes that are toxic to Gram-positive bacteria. EMB is the selective and differential medium for coliforms. It is a blend of two stains, eosin and methylene blue in the ratio of 6:1. EMB is a differential microbiological medium, which slightly inhibits the growth of Gram-positive bacteria and provides a color indicator distinguishing between organisms that ferment lactose and those that do not. Organisms that ferment lactose display "nucleated colonies"—colonies with dark centers.
A growth medium or culture medium is a solid, liquid, or semi-solid designed to support the growth of a population of microorganisms or cells via the process of cell proliferation or small plants like the moss Physcomitrella patens. Different types of media are used for growing different types of cells.
A fecal coliform is a facultatively anaerobic, rod-shaped, gram-negative, non-sporulating bacterium. Coliform bacteria generally originate in the intestines of warm-blooded animals. Fecal coliforms are capable of growth in the presence of bile salts or similar surface agents, are oxidase negative, and produce acid and gas from lactose within 48 hours at 44 ± 0.5°C. The term "thermotolerant coliform" is more correct and is gaining acceptance over "fecal coliform".
Indicator bacteria are types of bacteria used to detect and estimate the level of fecal contamination of water. They are not dangerous to human health but are used to indicate the presence of a health risk.
The 3M Petrifilm plate is an all-in-one plating system made by the Food Safety Division of the 3M Company. They are heavily used in many microbiology-related industries and fields to culture various micro-organisms and are meant to be a more efficient method for detection and enumeration compared to conventional plating techniques. A majority of its use is for the testing of foodstuffs.
Microbial art, agar art, or germ art is artwork created by culturing microorganisms in certain patterns. The microbes used can be bacteria, yeast, fungi, or less commonly, protists. The microbes can be chosen for their natural colours or engineered to express fluorescent proteins and viewed under ultraviolet light to make them fluoresce in colour.
The Triple Sugar Iron (TSI) test is a microbiological test roughly named for its ability to test a microorganism's ability to ferment sugars and to produce hydrogen sulfide. It is often used to differentiate enteric bacteria including Salmonella and Shigella.
The IMViC tests are a group of individual tests used in microbiology lab testing to identify an organism in the coliform group. A coliform is a gram negative, aerobic, or facultative anaerobic rod, which produces gas from lactose within 48 hours. The presence of some coliforms indicate fecal contamination.
Hektoen enteric agar is a selective and differential agar primarily used to recover Salmonella and Shigella from patient specimens. HEA contains indicators of lactose fermentation and hydrogen sulfide production; as well as inhibitors to prevent the growth of Gram-positive bacteria. It is named after the Hektoen Institute in Chicago, where researchers developed the agar.
Endo agar is a microbiological growth medium with a faint pink colour. Originally developed for the isolation of Salmonella typhi, it is now used mostly as a coliform medium. Most gram-negative organisms grow well in this medium, while growth of gram-positive organisms is inhibited. Coliform organisms ferment the lactose in this medium, producing a green metallic sheen, whereas non-lactose-fermenting organisms produce clear, colourless colonies, i.e. Salmonella species.
Thiosulfate–citrate–bile salts–sucrose agar, or TCBS agar, is a type of selective agar culture plate that is used in microbiology laboratories to isolate Vibrio species. TCBS agar is highly selective for the isolation of V. cholerae and V. parahaemolyticus as well as other Vibrio species. Apart from TCBS agar, other rapid testing dipsticks like immunochromatographic dipstick is also used in endemic areas such as Asia, Africa and Latin America. Though, TCBS agar study is required for confirmation. This becomes immensely important in cases of gastroenteritis caused by campylobacter species, whose symptoms mimic that of cholera. Since no yellow bacterial growth is observed in case of campylobacter species on TCBS agar, chances of incorrect diagnosis can be rectified. TCBS agar contains high concentrations of sodium thiosulfate and sodium citrate to inhibit the growth of Enterobacteriaceae. Inhibition of gram-positive bacteria is achieved by the incorporation of ox gall, which is a naturally occurring substance containing a mixture of bile salts and sodium cholate, a pure bile salt. Sodium thiosulfate also serves as a sulfur source and its presence, in combination with ferric citrate, allows for the easy detection of hydrogen sulfide production. Saccharose (sucrose) is included as a fermentable carbohydrate for metabolism by Vibrio species. The alkaline pH of the medium enhances the recovery of V. cholerae and inhibits the growth of others. Thymol blue and bromothymol blue are included as indicators of pH changes.
The citrate test detects the ability of an organism to use citrate as the sole source of carbon and energy.
Lysine iron agar or LIA is a differential media used to distinguish bacteria that are able to decarboxylate lysine and/or produce hydrogen sulfide from those that cannot. This test is particularly useful for distinguishing different Gram-negative bacilli—especially among the Enterobacteriaceae.
Sporosarcina ureae is a type of bacteria of the genus Sporosarcina, and is closely related to the genus Bacillus. S. ureae is an aerobic, motile, spore-forming, Gram-positive coccus, originally isolated in the early 20th century from soil. S. ureae is distinguished by its ability to grow in relatively high concentrations of urea through production of at least one exourease, an enzyme that converts urea to ammonia. S. ureae has also been found to sporulate when environmental conditions become unfavorable, and can remain viable for up to a year.
Rhodomicrobium vannielii is a Gram-negative, purple non-sulfur, motile, thermophilic photoheterotroph bacterium. Phototrophic bacteria are ubiquitous and have been reportedly found in many marine and terrestrial ecosystems. Additionally, they can use light as an energy source and carbon dioxide as a carbon source. Considering this, R. vannielii is thought to have potential application in anaerobic treatment and bioremediation under high temperature conditions as the bacteria was isolated from water samples from a hot spring in Gadek, Malacca, Malaysia using glutamate-malate medium (GMM) and Pfennig's M2 medium. R. vannielii produces acyclic and aliphatic cyclic carotenoids like anhydrorhodovibrin, rhodovibrin, spirilloxanthin and rhodopin.
An inoculation needle is a laboratory equipment used in the field of microbiology to transfer and inoculate living microorganisms. It is one of the most commonly implicated biological laboratory tools and can be disposable or re-usable. A standard reusable inoculation needle is made from nichrome or platinum wire affixed to a metallic handle. A disposable inoculation needle is often made from plastic resin. The base of the needle is dulled, resulting in a blunted end.
Diagnostic microbiology is the study of microbial identification. Since the discovery of the germ theory of disease, scientists have been finding ways to harvest specific organisms. Using methods such as differential media or genome sequencing, physicians and scientists can observe novel functions in organisms for more effective and accurate diagnosis of organisms. Methods used in diagnostic microbiology are often used to take advantage of a particular difference in organisms and attain information about what species it can be identified as, which is often through a reference of previous studies. New studies provide information that others can reference so that scientists can attain a basic understanding of the organism they are examining.
