Normal Flora And Bacteria Identification Biology

The human organic structure is of course inhabited by a broad assortment of bugs, jointly referred to as normal vegetations. To look into the diverseness of these bugs at different sites of the organic structure, swabs were taken from the tegument behind the ear and dorsum of the pharynx and cultivated on blood agar and Osmitrol salt agar home bases. Based on settlement morphology and Gram staining, Staphylococcus Aureus and Escherichia Coli were tentatively identified as the most outstanding normal vegetations cultured from the tegument and pharynx severally.


To cultivate normal flora nowadays on human tegument and in the pharynx utilizing differential selective media.

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To place the specific bacteriums grown from each part by detecting the morphology of the settlements on the agar home bases and Gram stained slides.


The human organic structure is inhabited by a broad assortment of bugs. In a healthy human internal tissue are usually free of micro-organisms whereas surface tissues are in changeless contact with environmental beings and go readily colonized by certain microbic species ( Toddar 2005 ) . The mixture of beings on a regular basis found at any anatomical site is referred to as the normal vegetations or normal biology. Each organic structure surface has its ain characteristic occupant biology made up of peculiar microbic species ( Ingraham & A ; Ingraham, 2004 ) . The type of bacteriums found in a certain location depends on environmental demands such as ideal temperature, pH, physiology and available foods. For illustration, countries such as the axilla, umbilicus or the dorsum of the pharynx seaport more micro-organisms due to the added wet, higher organic structure temperature and greater concentration of skin surface lipoids ( Baron 1996 ) .

To assistance in the isolation and designation of single types of bacteriums present in our normal vegetations specialized growing media can be used. Selective media is used to either encourage or suppress growing depending on the phenotype of the being. In add-on, differential media can assist place between two closely related bacteriums that have little phenotypic differences ( Ingraham & A ; Ingraham, 2004 ) . Blood agar and Osmitrol salt agar are illustrations of normally used media that are both selective and differential, helping in the growing publicity, designation and favoritism of common human normal vegetation. This survey aims to look into and place the normal flora diverseness found on the human organic structure utilizing these standard microbiology techniques.


Resident bacteriums were sampled from two anatomical sites, the tegument behind the ear and the dorsum of the pharynx. Blood agar and Osmitrol salt agar home bases were used ; incubation clip was 24 hours at temperature of 37AA°C. Gram staining trials and hemolysis were applied to observe settlements and place them.


A figure of different settlements were observed on both agar home bases following isolation of normal vegetations from the tegument and pharynx. Table 1 outlines the settlement description, blood agar hemolysis and subsequent Gram discoloration from both anatomical sites sampled. On both home bases Cocci bacteriums were identified ; Gram positive were present at both BA home bases, and Gram negative bacteriums were merely identified at the dorsum of the pharynx. Types of hemolysis were besides different: beta type for sample from the tegument, and gamma type for pharynx sample.

Table 2 presents the findings of normal flora settlements grown on Osmitrol salt agar. The differences between MSA settlements were more important than between BA settlements: samples from the dorsum of the pharynx were Gram negative, and samples from the tegument behind the ear were Gram negative. Based on these observations and cognition of the most abundant normal vegetations at each site, a preliminary designation of the bacteriums isolated was made. The bacterium in the pharynx is most likely Escherichia Coli and Staphylococcus Aureus bacterium is most likely to be identified at the tegument.

Table 1: Colony morphology and Gram discoloration of resident bugs from the tegument and pharynx, isolated on blood agar.


Colony Morphology


Cell Morphology

Gram Stain


Filamentous level shaped



Enterococcus aureus

Escherichia coli

Gram negative and Gram positive


Round convex shaped



Staphylococcus aureus ( 25 % common )

Streptococcus pyogenes ( 5 % rare )

Gram positive

Table 2: Colony morphology and Gram discoloration of resident bugs from the tegument and pharynx, isolated on Osmitrol salt agar.


Colony Morphology

Coloring material

Cell Morphology

Gram Stain


Punctiform level shaped

No colour


Neisseria sp.

Neisseria meningitides

Escherichia coli

Proteus sp.






Gram negative


Punctiform level shaped

Small pink or ruddy settlement




Staphylococcus aureus

Streptococcus pyogenes

Corynebacteria ( Bacilli )

Gram positive


To look into the diverseness of normal vegetations, countries from the tegument and pharynx were sampled and the occupant bacteria isolated on blood agar and Osmitrol salt agar home bases, prior to Gram staining.

BA home bases are differential: MSA home bases are selective and differential. Cultures grew on each half of the home bases. The consequences obtained at BA and MSA home bases are different ; this may ensue from several factors: sampling fluctuations, growing fluctuations and approximateness of estimations produced by Gram staining. For pharynx swabs, consequences were negative and positive at BA home base, and merely negative at MSA home base ; for tegument swabs, Gram consequences were positive at both home bases. At both halves of the home bases major settlements could be identified.

By and large, it was expected to attest greater assortment of bacteriums at the pharynx swab compared to clamber swab establishing on the difference of environments ( humidness, higher temperature, exposure to different micro-organisms ) . During the experiment, a somewhat greater diverseness was so observed. Escherichia Coli was determined as major settlement at pharynx sample because BA home base demonstrated gamma hemolysis and the pharynx swab shown Gram-negative consequences both times ( and Gram-positive consequences merely at BA home base ) . Different forms of settlements besides correspond to this designation as E. Coli does non hold a peculiar cell agreement. Staphylococcus aureus were determined as type of settlement for tegument swab since of its settlement type, beta hemolysis reaction and Gram-positive discoloration, 25 % common. Besides, Staphylococcus aureus is common for the normal vegetations of worlds found on rhinal transitions, tegument and mucose membranes ( Bauman 2008 ) , In order to do more elaborate analysis, it is possible to execute catalase trial.

To do a decision, the consequences of the experiment show the diverseness and preliminary designation of common normal vegetations found occupant on the tegument and pharynx.

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Normal Flora And Bacteria Identification Biology. (2016, Dec 09). Retrieved from