Identification of Bacteria

Introduction 

The process of “identification of bacteria” is commonly done by either using biochemical tests or by performing morphological tests. A few procedures of “identification of bacteria” involve the use of supplements such as antibiotic inhibition tests, starch utilization tests, tests for identifying the capability of producing biofilms, and citrate utilization tests. On the other hand, “identification of bacteria” also involves advanced molecular and cellular techniques that help the strain to be identified by the sequence of genes. 

Discussion

Principle

“Isolation and identification of bacteria” involves a series of steps. Isolation of criteria is generally done by obtaining a strain by growing it on pure bacterial cell culture. In order to isolate a strain by using the pure culture method, the first step is the identification of the bacteria. “Isolation and identification of bacteria” is important in the study of physiology, morphology, and identification of susceptibility to several antimicrobials. The first step of “identification of bacteria” involves the isolation of bacteria which is generally done by using streak plate or pour plate method. In this regard, streak plate is considered as the most effective method of “Isolation and identification of bacteria”. On the other hand, “bacterial identification methods” can be done by using several methods including “Biochemical tests”, “Staining and microscopic techniques”, using “Immunological test”, PCR as well as microarray-based techniques. Hence bacterial species are identified and defined specifically that they are a combination of similar identified strains.

Methods of isolation of bacteria “Isolation and identification of bacteria” is the selection of media for the growth of the bacteria. Depending on the specific growth needs of the bacteria a suitable method is selected. In this regard, examples of such mediums include TSA or “tryptic soy agar”, BSA or Bovine serum albumin, NA or “Nutrient agar media”. In this case, the most commonly used growth media is NA. Besides, regarding the specific needs of certain strains there are several selective media that include TCBS or “thiosulfate citrate bile sucrose” agar media for growing Vibrio’s, GSP, or “Glutamate starch phenol” agar media for the growth of aeromonads as well as pseudomonads. Furthermore, pH and temperature also play a crucial role in the process of isolation of bacteria. 

Methods of identification of bacteria

Streak plate method

“Streak plate method” is the most commonly used method for the identification of bacteria. The technique involves transferring a colony of bacteria from a pure agar or broth culture into another sterile growth agar media. The first step, in this case, is to pour the growth media into a sterile Petri plate, allowing it to solidify, streaking a bacterial colony on the growth medium using a particular pattern and incubating. 

Spread plate method

 “Pour plate method” involves pouting bacterial cells suspended in a culture media into another sterile growth media. In this case, a certain amount of culture is taken by using a micropipette, poured in the Petri plate, then the cell culture is evenly spread within the plate with a sterile plate and incubated for a certain period

Pour plate method

It includes the serial dilution of bacterial cells. In this case a specific amount of the dilution is taken and placed into a sterile plate. Furthermore, a melted agar media that is cooled to around 45 degrees Celsius is poured into the plate and incubated overnight

Bacterial identification methods

Microscopic techniques

This is considered as one of the most widely implemented techniques for “bacterial identification methods”. In this regard, in order to make the bacterial strains visible, they are stained. In this case, the widely used technique is “Gram staining” which includes the differentiation of Gram-positive and gram-negative bacteria. The test is based on the structure of the peptidoglycan layer. On the other hand, Endospore staining involves the application of a staining agent to identify the ability of the strain to produce spores which indicates the virulence of the strain. In order to identify “Mycobacterium species” the Ziehl-Neelsen Staining method is used. 

 Biochemical Tests

Biochemical tests are important for the “IDENTIFICATION OF BACTERIA”. In the case of the “catalase test”, the catalase activity of a bacteria is determined. This is done to identify Micrococci, E. coli.as well as staphylococcus strains which are considered as catalase-positive strains. Similarly, other biochemical tests include the oxidase test by which the anaerobes and aerobes are detected, substrate utilization tests that is used for industrial purposes

Other tests for “identification of bacteria” include PCR, Microarray tests, and immunological tests such as “ELISA”, “RIA”.

Conclusion

The “identification of bacteria” involves several steps including the isolation of bacteria and identification of the same.In this regard, the main traits that are used to distinguish a strain from others for “identification of bacteria”  includes the structure of DNA-weather is double-stranded or single-stranded, RNA-double stranded or single-stranded, the molecular composition of the outer layer of the strain i.e. the structure of peptidoglycan layer, presence of organelles that are membrane-bound at a proper manner.