Anti Bacteriology - a Much Needed Medical Innovation
The discovery of microorganisms dates back to the 17th century by two members of The Royal Society, one being the Father of microorganism Antoni van Leeuwenhoek. The first-ever microorganism to be published was microfungus Mucor. As per the new estimates, there are many species of microbes, 99.9% still to be discovered. The most common ones among the huge lot are bacteria, viruses, fungi, Archaea etc. One of the first life forms on Earth, bacteria which is a few micrometres long, is a type of biological cell consisting of prokaryotic microorganisms.
Antibacterial testing - modernizing Micro Biology
Antibacterial testing refers to the process of observing the degree of resistance created by an anti bacterium against bacteria. Anti bacterium refers to those substances which either destroy or restrict the multiplying of the bacteria by suppressing their ability of asexual reproduction. The first anti-bacteria to be available commercially was Prontosil, which is a sulphonamide founded by German biochemist Gerhard Domagk. The main concept of anti-bacteria is to make the environment highly inhospitable for the bad bacteria to survive in it. Antibacterial testing method reveals the level of effectiveness an antibacterial drug can achieve against a certain bacteria. This test provides detailed information regarding the clinical action to be taken. The tests are generally performed in a medical laboratory with highly specialised equipment through various methods.
Antibacterial testing and its types
Antibacterial testing, which can be performed in a highly equipped medical laboratory, has various methods, the most common ones being
Phenotypic methods - Under this method, the bacteria are exposed to the anti-bacteria using an Agar plate. This method is done without making any alterations in the genes of bacteria. A few methods under the category are:-
- Agar disk diffusion method- the standardized procedure has been introduced to test pathogens like streptococci, Haemophilus influenzae, Haemophilus parainfluenzae, Neisseria Gonnorhoeae and Neisseria Meningitidis.
- Agar plug diffusion method – used to portray the antagonism between microorganisms and has the same procedure as the previous one.
- Cross Streak method – used to rapidly detect the microbes.
- Poisoned food method- determines the antifungal effects against the moulds.
- Gradient Method – Under this method, a plastic strip impregnated with different anti-bacterium concentrations and is placed on an agar plate. Then the growth is observed after a period of time which is known as the incubation period. Sometimes, multiple strips having different anti bacterium may be used for conducting tests.
- Matrix-assisted laser desorption ionisation- time of flight mass spectrometry (MALDI- TOF-MS) – Another type of phenotypic testing method used in modern times. Under this method, an automated system MALDI-TOF is used to analyze the growth of the strain of a bacteria. However, this method is more complex and expensive as compared to the other methods.
Genetic Method - This method is to determine whether the strain of bacteria possess genes that might provide it resistance against the anti-bacteria. Following are some methods used under this type:-
- Polymerase Chain Reaction (PCR) - The process mainly targets identifying the genes related to antibiotic susceptibility. Under this process, a bacteria’s gene is denatured, and then a DNA polymerase is added alongside the mixture containing molecules like nucleotides and ions. After the completion of the process, the presence of the genes is demonstrated through various analysis methods like DNA sequencing and electrophoresis.
- DNA microarrays – also known as DNA chips, are a collection of microscopic spots of DNA that are found attached to a solid surface. This technique uses the bindings of the complementary DNA to target a specific gene or a sequence of nucleic acids. This method is highly effective as it can easily assess multiple genes simultaneously.
Requirement for the test
The first and foremost requirement is quality control assurance which includes all the diagnostic tests. The main objective of the quality control mechanism is to ensure the accuracy of the test method. The reagents, medium, equipment and discs put to use should be of supreme quality. The result so obtained should be accurately interpreted. The problems like the wrong stain used, improper storage facility, use of contaminated material or defective agar plates should be avoided. The testing procedure should be accurately carried on as it is very useful also in the clinical treatment of diseases caused due to bacteria. The calibration functioning should be done properly. The selection of the right agents, equipment are essential for maintaining the effectiveness of the procedure being carried out. Proper precaution should be taken because this testing is very useful as it is a major portion of clinical treatment.
The testing helps the doctors to suggest proper medication to a patient suffering from a bacterial disease. Mostly the medicines are prescribed by taking into account a person’s symptoms; this method is called Empiric theory. Under this technique, the type of bacteria that has affected a person is first and identified and then a proper antibacterial drug for it is prescribed. Continuous effort is being made to reduce resistant bacteria, which causes infections leading to fatal disease. According to the estimates, there are one trillion microbes presently discovered, which is only 0.1 per cent of the total microorganisms present, 99.9% yet to be found. But the rapidly advancing and upgraded medical sciences will leave no stones unturned to improve the process of Antibacterial testing.
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