Identification of Bacteria

hello everyone hope you all are doing good so this video mainly focuses on staining techniques and the Culture Media used for the bacteria so as you all know when it comes to staining techniques the gram staining is the most commonly used for differentiating the large group of bacteria that is gram positive and gram negative so here the procedure is important to know so there are the four steps present in gram staining that is application of the crystal violet which is the first step that is primary stain so crystal violet is a purple dye which is used and the second step in gram staining is application of iodine which acts like a modern that means fixing the primary step so it fixes the primary stain and after the application of primary stain that is crystal wallet and the secondary step that is application of iodine the alcohol wash is done which acts as a D staining procedure that is decolorization and the last step is application of counter stain that is safranin which is pink in color so the summary is the bacteria which retains the primary stain that is the crystal violet are considered to be gram positive bacteria and the bacteria which loses the primary stain and takes up the counter stain is gram-negative bacteria so here you can see in the bottom of the slide the view of gram-positive and gram-negative bacteria on the microscopic slide so the bacteria which retains the primary strain curve that is purple that is crystal violet is considered to be gram positive whereas the bacteria which is pink in color which takes up safranin is gram-negative bacteria so the reason for gram-positive bacteria which doesn't get decal raised is the thick peptidoglycan layer so that the thick peptidoglycan layer makes it retain the primary stain that is crystal wallet so that it appears purple or blue in color whereas the gram-negative bacteria does not have thick peptidoglycan layer it loses the primary stain and takes up the counter strain that is safranin so these are the examples of gram positive bacteria only so this is the mnemonic for gram positive bacteria that is strange stuff is at least entered my new carry bag is the mnemonic for remembering gram positive bacteria examples so the bold letters that is dark black letters represents a bacteria so strange for streptococcus Steffie Staphylococcus act for act no - list for Listeria entered that is Enterococcus my for a micro bacteria new for pneumococcus carry for corynebacterium and bag for bacillus so strange stuff is at least entered my new carry bag is a mnemonic for gram positive bacteria moving on to the other staining technique that is acid fast staining also called as ZL nielsen staining procedure so in this it is also included with four steps that is application of primary stain that is carbon question and instead of using iodine here the slide is heated which acts like a modern that is fixated so application of heat is animating step between gram staining and acid first and the third is the same that is application of acid alcohol which acts as a decal raiser and the final is application of methylene blue that is counter stain so acid first bacteria are mainly done for micro bacterium that reason for that is because of the presence of my colic acids in the cell wall so high amount of my chronic acids present in the cell wall so that's why gram staining is not preferred for micro bacterium as it first training is preferred so the summary of this staining technique is the acid fast bacteria because of presence of high mykola gases they do not get decolorized they appear bright red in color whereas the known as it first bacteria takes up the counter stain that is methylene blue so here is a clear picture of gram positive gram negative and acid fast bacteria so here you can see gram positive bacteria has a thick peptidoglycan layer whereas gram-negative bacteria has thin peptidoglycan layer and like important feature of gram-negative bacteria is presence of outer membrane and as it first bacteria you can see parents of high mycolic acid content coming to the bacterial growth curve many questions are urged regarding this growth curve so there are four phases in bacterial growth curve that is lag phase logarithmic phase stationary phase and death phase so the important events occurring in these phases are very important so the events that are occurring in the first phase that is lag phase are adaptation of the bacteria to this environment and the maximum cell size is attained by the bacteria by the end of this logarithm log lag phase whereas the second phase that is logarithmic phase is also called as exponential phase here the cells are stained uniformly and the bactericidal drugs are more active in this logarithmic phase the third phase is stationary phase because there is zero growth rate and the important feature that happens here is the sporulation and the final phase is the death phase that is the phase of decline and the involution forms are more common in this death phase so please remember lag phase logarithmic phase also called as exponential phase stationary phase also called as zero growth rate phase and death phase also called as phase of decline moving on to the culture media so culture media you need to remember the media name and the bacteria example so the main users of culture media is the primary uses to identify the bacteria that is cause of infection from a given clinical sample so if you identify the perfect bacteria given in the king and sample the clinician can suggest the proper drug against it so that the proper treatment can be given and it is also used to study the characteristics and the properties of the microorganisms and last but not least is to prepare biological products like vaccines so there are the three types of Culture Media it can be either solid liquid or semi solid please remember solid consists of agar so if you add 2 percent of agar to the Culture Media it is considered to be a solid media if there is no agar in the medium it is considered to be liquid medium and if there is a less concentration of agar like 0.2 to 0.5 this semi solid so whenever there is agar mentioned in the given Culture Media that means it is solid in nature whenever there is broth mentioned it is liquid invention and there are aerobic and anaerobic medians aerobic media is for the bacteria which can easily grow in the presence of oxygen whereas anaerobic media which cannot be grown in the presence of oxygen the examples of anaerobic media are commonly us that is robertson cooked meat broth and taiyo glycolate medium coming to the classification so calcium in a glass fed into simple complex and synthetic media so simple media the examples of simple media nutrient broth or nutrient agar so new tentacle is nothing but a guarded - nutrient broth so 2 percent of agar added to nutrient broth makes it nutrient agar apart from simple media their synthetic and complex media so you need to know the difference between synthetic and complex synthetic media contain ingredients for which complete chemical formula is known that is example is if Pepitone water is used as a media it is considered as synthetic medium because complete chemical formula is known it consists of 1% peptone 0.5 percent sodium chloride in water whereas complex media the chemical formula is not perfectly known such as milk egg malt and animal dishes are added so perfect chemical composition is not known in complex media where a synthetic media also called as defined media the chemical composition of every component is well known so we will discuss about different complex media which are very very important regarding need so the first one is enriched media so here you can remember n reached the d stands for solid so enriched media is already in nature so as I told you the examples of solid media should contain agar so whichever media consists of agar in it mostly come under enriched media so blood agar chocolate agar and LeFleur serum slope comes under enriched media that is solid in nature so difference between blood agar and chocolate agar so the appearance can be seen here so blood agar consists of mammalian blood chocolate agar also contain red blood cells that have been lized by slow heating to 80 degree Celsius so played agar is more mostly used to detect the hemolytic pattern of the bacteria very very important so blood agar is a agar used for detecting fastidious organisms or to isolate them and to detect the hemolytic pattern of the bacteria so this is the hemolysis pattern so there are three types of hemolytic pattern you can see beta hemolysis alpha hemolysis and gamma hemolysis in the diagram you can see beta hemolysis means complete lysis of the red blood cells there as alpha hemolysis is partial lysis of the red blood cells whereas gamma hemolysis you can see there is no lysis of red blood cells so alpha hemolysis you can see there is partial hemolysis the greenish colonies are seen in alpha hemolysis so that is the point to be noted so beta hemolysis is complete hemolysis alpha is partial hemolysis and gamma is no hemolysis so these are the examples of different hemolytic patterns beta hemolytic streptococcus pyogenes alpha is e---coli and gamma that is no hemolysis Staphylococcus epidermis moving on to the second complex meter that is enrichment medium so enriched media is solid in nature whereas enrichment media is liquid in nature so it is also called as liquid selective medium so as I told you if it consists of broth that if the example consists of broth in the name it is considered to be liquid in nature so enrichment media is nothing but liquid in nature the examples are tetra thionite broth which is mainly for Salmonella cell native broth which is my first Salmonella and shegella whereas alkaline peptone water is for Librium so there are three examples of enrichment medium so blood agar chocolate agar Loffler serum slope are examples of enriched media which are solid in nature whereas tetra thinit broth selenite f broth and alkaline crypto water are examples of enrichment media which are liquid invention the third is selective media so enrichment media is also a type of selective media but liquid in nature whereas selective media is solid in nature so the examples of selective media is thiosulfate citrate bile salt sucrose Agha that is tcbs for rib rio the Bernstein's Jenson's media for micro bacterium tuberculosis so with in selective media there is substance that is added to slow down the growth of specific bacteria and only the bacteria that is tend to grow is grown that is in tcbs it enhances the growth of Vibrio whereas in LJ media that is the one shinkansen media now let's eat green dye which is present Awards of other bacteria and enhances the growth of Mycobacterium tuberculosis and the other example of selective media is ther marked in medium apart from PCBs and LJ media ther marked in medium also included under selective area so ther Martin median is nothing but as you can see in the diagram it is a chocolate agar with added vancomycin and missed rattle that is anti bacterial Sony Syria is an example for ther Martin medium so a Syria is grown on they are marked in middle moving on to the indicator media so the name itself suggests the media contains an indicator that is color indicator which changes in color when the bacteria grow in them so the examples of indicator media is builds and Blair medium and Mike Loades made him so here you can see in the diagram the Wilson Blair medium because of the growth of the bacteria the sulphide is converted into sulfide that is black metallic colonists so because of the growth of Salmonella typhi the sulfide is converted into sulfide so Wilson and Blair medium is for Salmonella typhi whereas metalloids medium for corynebacterium diphtheria so here the potassium daily rate is reduced to metallic delirium so whenever there is a change in color it is considered to be indicator media so Salmonella typhi is indicated by growth of black color black color colonist in Wilson and blade medium whereas corynebacterium diphtheria in McClure it's medium and differential medium so it is used to distinguish between the bacteria that is lactose fermenting or non lactose fermenters so McConkey saga is an example for differential medium so here you can see the lactose fermenting bacteria appears pink in color whereas non lactose fermenters appears colorless and the final Culture Media is transport medium so it is used to transport the organism from the lab from the collecting area so the examples of transport medium is Cary Blair for Salmonella she's ill and Vibrio whereas Stuart's medium for transportation of go knock okay so it is used to preserve the particular type of bacteria and also prevents the growth of unwanted bacteria during the transport from the collecting area to the laboratory so the examples are clearly Blair and stores carry Blair for Salmonella she jail and Vibrio whereas towards medium for going off okay and there are specific media for fungal growth the main and most commonly used ISA Burroughs glucose or agar are sub rods dextrose agar and inhibitory molar these two are important for the growth of fungus most commonly asked question is suburbs Dijkstra Sagara sub rods glucose aha they are related to the fungal growth